methacholine chloride solution for inhalation 0.0625, 0.125, 0.25, 0.5, 1, 2, 4, 8, and 16 mg/mL
Pr PROVOCHOLINE(r) methacholine chloride powder USP 100 mg, 160 mg, 320 mg, 1280 mg and 1600 mg Cholinergic / Diagnostic Aid (Bronchial Asthma) Methapharm Inc. Date of Preparation: 31 May 2001 81 Sinclair Blvd. Brantford, Ontario Date of Revision: November 24, 2006 N3S 7X6 Control #105441
Table of Contents
SUMMARY PRODUCT INFORMATION 3 INDICATIONS AND CLINICAL USE 3 CONTRAINDICATIONS 4 WARNINGS AND PRECAUTIONS 4 ADVERSE REACTIONS 7 DRUG INTERACTIONS 7 DOSAGE AND ADMINISTRATION 8 OVERDOSAGE 23 ACTION AND CLINICAL PHARMACOLOGY 23 STORAGE AND STABILITY 24 SPECIAL HANDLING INSTRUCTIONS 24 DOSAGE FORMS, COMPOSITION AND PACKAGING 25
PHARMACEUTICAL INFORMATION 27 CLINICAL TRIALS 28 DETAILED PHARMACOLOGY 29 TOXICOLOGY 29 REFERENCES 30
methacholine chloride solution for inhalation 0.0625, 0.125, 0.25, 0.5, 1, 2, 4, 8, and 16 mg/mL
Pr PROVOCHOLINE(r) (methacholine chloride powder USP) 100 mg, 160 mg, 320 mg, 1280 mg and 1600 mg
| Route of Administration | Dosage Form / Strength | Clinically Relevant Non-Medicinal Ingredients |
| Inhalation | Powder: 100 mg, 160 mg, 320 mg, 1280 mg and 1600 mg Solution: 0.0625, 0.125, 0.25, 0.5, 1, 2, 4, 8, and 16 mg/mL | N/A Sodium acetate trihydrate Water for injection Sodium Chloride |
Provocholine(r) is indicated for:
Diagnosis of asthma (bronchial airway hyperresponsiveness)
Provocholine(r) (methacholine chloride) is indicated for the diagnosis of bronchial airway hyperresponsiveness in subjects suspected of having asthma. The methacholine challenge test with Provocholine(r) provides a measure of the severity of asthma. The methacholine challenge test with Provocholine(r) may be used to confirm occupational asthma. The product should be administered under the supervision of a qualified health professional who is experienced in the use of inhalation agents and in the management of patients experiencing severe bronchoconstriction. Appropriate management of therapy and complications is only possible when adequate diagnostic and treatment facilities are readily available.
Geriatrics
: No data is available.
Pediatrics (<5 years of age): The safety and efficacy of methacholine challenge tests with Provocholine(r) have not been established in children below the age of 5 years.
Provocholine(r) (methacholine chloride) is contraindicated in patients with known hypersensitivity to this drug or to other parasympathomimetic agents.
A repeat challenge test on the same day is contraindicated.
b
-agonists, anticholinergics and theophylline may be contraindicative (See DRUG INTERACTIONS)
Provocholine(r) is to be administered only by inhalation. See Warnings and Precautions - General Provocholine(r) is a bronchoconstrictor agent for diagnostic purposes only, and should not be used as a therapeutic agent. See Warnings and Precautions - General Sterile Provocholine(r) Solution 16 should only be used without prior dilution if using an approved device that regulates the dosage through its operation (consult specific manufacturer's instructions). When using Sterile Provocholine(r) Solution 16 with any other type of delivery system, Sterile Provocholine Solution 16 must be diluted prior to administration (see DOSAGE AND ADMINISTRATION). Administration of the MAXIMUM DOSE (16 mg/mL) without prior dilution can result in severe and sudden bronchoconstriction. Patients with severe hyperresponsivness of airways can experience bronchoconstriction at the lowest dosages or with the diluent alone. See Warnings and Precautions - Respiratory Test should not be performed on any patient with baseline FEV1 of less than 1.5 litres or 70% of predicted value. See Warnings and Precautions - Respiratory When administered orally or by injection Provocholine(r) is associated with nausea, vomiting, substernal pain or pressure, hypotension, fainting and transient complete heart block. See
When administered orally or by injection overdosage can result in a syncopal reaction, with cardiac arrest and loss of consciousness. See Overdosage Baseline spirometry must be accurate. If not, the initial FEV1 maybe underestimated, and subsequent falls after inhaling Provocholine(r) solutions may not be detected, resulting in too high a dose and excessive bronchoconstriction. See Warnings and Precautions - General
General
Provocholine(r) (methacholine chloride) is to be administered only by inhalation. Provocholine(r) (methacholine chloride) is a bronchoconstrictor agent for diagnostic purposes only, and should not be used as a therapeutic agent. Administration of Provocholine(r) to patients with epilepsy, cardiovascular disease accompanied by bradycardia, vagotonia, peptic ulcer disease, thyroid disease, urinary tract obstruction or other condition that could be adversely affected by a cholinergic agent should be undertaken only if the physician feels the benefit to the individual outweighs the potential risks. It is essential that the baseline spirometry is accurate. If the baseline spirometry is not performed or measured accurately, and the initial FEV1 is underestimated, subsequent falls after inhaling Provocholine(r) solutions may not be detected, resulting in too high a dose and excessive bronchoconstriction. Methacholine challenge test with Provocholine(r) should be performed only under the supervision of a physician trained in and thoroughly familiar with all aspects of the technique of methacholine challenge, all contraindications, warnings and precautions, and the management of respiratory distress. A physician responsible for the tests must be present in the building when tests are carried out, and available to be contacted quickly if necessary. If the physician is performing the test, another person must be available in the building to give assistance if required. The patient must never be left unattended during the test. Emergency medication and equipment should be immediately available to treat acute respiratory distress.
Carcinogenesis, Mutagenesis and Impairment of Fertility
There have been no studies with methacholine chloride that would permit an evaluation of its carcinogenic or mutagenic potential or of its effect on fertility.
Cardiovascular
Administration of Provocholine(r) to patients with cardiovascular disease accompanied by bradycardia, which could be adversely affected by a cholinergic agent, should be undertaken only if the physician feels benefit to the individual outweighs the potential risks.
Endocrine and Metabolism
Administration of Provocholine(r) to patients with thyroid disease, which could be adversely affected by a cholinergic agent, should be undertaken only if the physician feels benefit to the individual outweighs the potential risks.
Gastrointestinal
Administration of Provocholine(r) to patients with peptic ulcer disease, which could be adversely affected by a cholinergic agent, should be undertaken only if the physician feels benefit to the individual outweighs the potential risks.
Genitourinary
Administration of Provocholine(r) to patients with urinary tract obstruction, which could be adversely affected by a cholinergic agent, should be undertaken only if the physician feels benefit to the individual outweighs the potential risks.
Neurological
Administration of Provocholine(r) to patients with epilepsy, which could be adversely affected by a cholinergic agent, should be undertaken only if the physician feels benefit to the individual outweighs the potential risks.
Respiratory
Severe bronchoconstriction can result from the administration of Provocholine(r), if guidelines for careful administration are not followed. Patients with severe hyperresponsiveness of the airways can experience bronchoconstriction at the lowest dosages of Provocholine(r), or with the diluent (or placebo, as applicable) alone. If severe bronchoconstriction occurs, it should be reversed immediately by the administration of a rapid-acting inhaled ss-agonist. Because of the potential for severe bronchoconstriction, Provocholine(r) challenge should not be performed in any patient with low baseline FEV1 of less than 1.5 litres or less than 70% of the predicted value. Please consult standard nomograms for predicted values.1
Special Populations
Pregnancy: Teratogenic Effects - Animal reproduction studies have not been conducted with methacholine chloride. It is not known whether methacholine chloride can cause fetal harm when administered to a pregnant patient or affect reproductive capacity. Provocholine(r) should be given to a pregnant woman only when the benefits clearly outweigh the risks. Nursing Mothers: It is not known if methacholine chloride when inhaled is excreted in breast milk. Methacholine challenge test with Provocholine(r) should be administered to nursing mothers only when the benefits clearly outweigh the risks. Pediatric Use: The safety and efficacy of methacholine challenge tests with Provocholine(r) have not been established in children below the age of 5 years. Laboratory Personnel: Provocholine(r) aerosol may cause bronchoconstriction in laboratory personnel and others in the same room as the patient undergoing the test. Laboratory personnel with asthma or hay fever should take appropriate precautions when handling the material. (See SPECIAL HANDLING INSTRUCTIONS)
Information to be Provided to the Patient
To assure the safe and effective use of the methacholine challenge test with Provocholine(r), the following instructions and information should be given to patients: Patients should be educated in the symptoms that may occur as a result of the test, and instructed to alert the test administrator of these symptoms so that the test can be stopped before pulmonary function is reduced to less than 1.5 litres. Women of child-bearing age should be questioned on the possibility of pregnancy (See Special Populations - Pregnancy).
ADVERSE REACTIONS
Adverse reactions associated with inhaled methacholine challenge tests are rare, and include incidences of headache, throat irritation, light-headedness and itching. A positive reaction to methacholine challenge may produce symptoms of bronchospasm, such as chest tightness, cough or wheezing. Incidences of severe bronchoconstriction can be avoided by limiting the challenge test to cases of potentially mild asthma, in those patients with normal or near normal FEV1, and by cautiously increasing the dosage. Provocholine(r) (methacholine chloride) is to be administered only by inhalation. When administered orally or by injection, Provocholine(r) is reported to be associated with nausea and vomiting, substernal pain or pressure, hypotension, fainting and transient complete heart block. (See OVERDOSAGE)
Overview
Provocholine(r) (methacholine chloride) is a parasympathomimetic (cholinergic) bronchoconstrictor agent to be administered in solution only, by inhalation. Methacholine chloride is the ss-methyl homolog of acetylcholine, is slowly hydrolysed by acetylcholinesterase and almost totally resistant to inactivation by non-specific cholinesterase or pseudocholinesterase.
Drug-Drug Interactions
Precaution should be taken when the inhalation challenge is performed in patients receiving any ss-adrenergic blocking agents, as it is possible that bronchoconstriction may not reverse as readily. The following asthma and hayfever medications inhibit the response of airways to Provocholine(r), and should be withheld before the test, for their duration of action: ss-agonists, anticholinergics and theophylline. Corticosteroids, cromoglycate and nedocromil, after regular use, may alter Provocholine(r) responsiveness but they do not do this acutely; thus, they may be continued in their regular dose before any test. The effects of other newer medications have not been investigated.
Drug-Food Interactions
Methacholine chloride can be administered without regards to timing of meals.
Drug-Herb Interactions
The interactions of methacholine chloride with herbal medications or supplements have not been established.
Drug-Laboratory Test Interactions
The interactions of methacholine chloride with laboratory tests have not been established.
Recommended Dose and Dosage Adjustments
For Provocholine(r) Powder (methacholine chloride USP), adults and children (5 years or older) are exposed to the following increasing concentrations: 0.03, 0.0625, 0.125, 0.25, 0.5, 1, 2, 4, 8 and 16 mg/mL. (See Tables 1A, 1B, 1C, 1D and 1E). For Sterile Provocholine(r) Solution (methacholine chloride), adults and children (5 years or older) are exposed to the following increasing concentrations: 0.0625, 0.25, 1, 4, and 16 mg/mL. For Sterile Provocholine(r) Solution Plus (methacholine chloride), adults and children (5 years or older) are exposed to the following increasing concentrations: 0.0625, 0.125, 0.25, 0.5, 1, 2, 4, 8 and 16 mg/mL. When using 1 vial of Sterile Provocholine(r) Solution 16 (methacholine chloride), adults and children (5 years or older) are exposed to the following increasing concentrations: 0.0625, 0.25, 1, 4, and 16 mg/mL. Alternatively, when using 2 vials of Sterile Provocholine(r) Solution 16 (methacholine chloride), adults and children (5 years or older) are exposed to the following increasing concentrations: 0.0625, 0.125, 0.25, 0.5, 1, 2, 4, 8 and 16 mg/mL. When using in conjunction with an approved device that delivers gradually increasing amounts of Sterile Provocholine(r) Solution 16 from the insertion of the maximum, supplied dosage of 16 mg/mL, manufacturer's instructions should be followed and it is not recommended to exceed a maximum total cumulative dose of 159.83 inhalation units (see Table 2).
Preparation of Dilutions:
Sterile Provocholine(r) Solution (methacholine chloride) and Sterile Provocholine(r) Solution Plus (methacholine chloride) are sterile, colourless solutions that do not require any dilution before administration. If necessary, before use, take 1 mL of the 0.0625 mg/mL solution and add 1 mL of sterile placebo solution for a resulting concentration of 0.03 mg/mL. Use immediately and discard any unused vials. Sterile Provocholine(r) Solution 16 (methacholine chloride) is a sterile, colourless solution that may be used without any further dilution with approved medical devices designed to deliver gradually increasing doses of Sterile Provocholine(r) Solution 16 from the insertion of the maximum, supplied dosage of 16 mg/mL, or diluted to varying lower concentrations with Sterile Baseline Solution and administered by either the tidal breathing or the dosimeter technique. Use immediately and discard any unused vials. Since the temperature of the solution affects nebulizer output, if storing Sterile Provocholine(r) Solution, Sterile Provocholine(r) Solution Plus, Sterile Provocholine(r) Solution 16 or Sterile Baseline Solution in the refrigerator they should be taken out and allowed to equilibrate to room temperature (approximately 30 minutes) before use. Table 1F describes a method of producing appropriate dilutions, using a single vial of Sterile Provocholine(r) Solution 16. Table 1G describes a method of producing appropriate dilutions, using 2 vials of Sterile Provocholine(r) Solution 16. NOTE: The packaged dose of 16 mg/ml should not be administered as an initial dose without prior dilution unless being utilized with an approved device that regulates the dosage through its operation. It is not recommended to exceed the equivalent of 2 mg/mL of Provocholine(r) for the initial aerosol when using any device or testing method. Consult manufacturer's instructions and published sources. Provocholine(r) Powder (methacholine chloride USP) requires dilution before use. All dilutions using Provocholine(r) Powder should be made with 0.9% sodium chloride solution for injection containing 0.9% benzyl alcohol, as suggested in Table 1A for Provocholine(r) 100 mg/vial, Table 1B for Provocholine(r) 160 mg/vial, Table 1C for Provocholine(r) 320 mg/vial, Table 1D for Provocholine(r) 1280 mg/vial and 1E for Provocholine(r) 1600 mg/vial in sterile USP Type I Glass vials. After adding the 0.9% sodium chloride solution for injection, shake each vial to obtain a clear solution. Check the date of preparation or expiry before using dilutions that are not freshly prepared. Provocholine(r) solutions prepared from powder and using aseptic technique may be stored in a refrigerator (2deg to 8degC) for up to 2 weeks. After this time, discard the vials and prepare new dilutions. Freezing does not affect the stability of the dilutions. Since the temperature of the solution affects nebulizer output, solutions should be taken out of the refrigerator and allowed to equilibrate to room temperature (approximately 30 minutes) before use. When using Sterile Provocholine(r) Solution, Sterile Provocholine(r) Solution Plus, Sterile Provocholine(r) Solution 16 or Provocholine(r) Powder, any unused solution should be discarded from the nebulizer after each concentration. Tables 1A, 1B, 1C, 1D and 1E describe methods of producing appropriate dilutions, using a single vial of Provocholine(r) Powder. NOTE: The initial dilutions of the 320 mg, 1280 mg and 1600 mg vials to obtain solutions of 32 mg/mL (320 mg and 1600 mg) or 128 mg/mL (1280 mg) are NOT to be administered to the patient during the methacholine challenge test with Provocholine(r). They are only used in the preparation of the 16 mg/mL and 8 mg/mL dilutions.
When preparing dilutions using Provocholine(r) Powder, a sterile bacterial-retentive filter (porosity 0.22 um) should be used when transferring a solution from each vial (at least 2 mL) to a nebulizer. This step is not required when using Sterile Provocholine(r) Solution, Sterile Provocholine(r) Solution Plus or Sterile Provocholine(r) Solution 16.
| TAKE | ADD NaCl 0.9% with 0.9% benzyl alcohol | OBTAIN DILUTION |
| 100 mg Provocholine (r) | 6.25 mL | 16 mg/mL (A) |
| 3 mL of dilution A | 3 mL | 8 mg/mL (B) |
| 3 mL of dilution B | 3 mL | 4 mg/mL (C) |
| 3 mL of dilution C | 3 mL | 2 mg/mL (D) |
| 3 mL of dilution D | 3 mL | 1 mg/mL (E) |
| 3 mL of dilution E | 3 mL | 0.5 mg/mL (F) |
| 3 mL of dilution F | 3 mL | 0.25 mg/mL (G) |
| 3 mL of dilution G | 3 mL | 0.125 mg/mL (H) |
| 3 mL of dilution H | 3 mL | 0.0625 mg/mL (I) |
| 3 mL of dilution I | 3 mL | 0.03 mg/mL (J) |
| TAKE | ADD NaCl 0.9% with 0.9% benzyl alcohol | OBTAIN DILUTION |
| 160 mg Provocholine (r) | 10 mL | 16 mg/mL (A) |
| 3 mL of dilution A | 3 mL | 8 mg/mL (B) |
| 3 mL of dilution B | 3 mL | 4 mg/mL (C) |
| 3 mL of dilution C | 3 mL | 2 mg/mL (D) |
| 3 mL of dilution D | 3 mL | 1 mg/mL (E) |
| 3 mL of dilution E | 3 mL | 0.5 mg/mL (F) |
| 3 mL of dilution F | 3 mL | 0.25 mg/mL (G) |
| 3 mL of dilution G | 3 mL | 0.125 mg/mL (H) |
| 3 mL of dilution H | 3 mL | 0.0625 mg/mL (I) |
| 3 mL of dilution I | 3 mL | 0.03 mg/mL (J) |
| TAKE | ADD NaCl 0.9% with 0.9% benzyl alcohol | OBTAIN DILUTION |
| 320 mg Provocholine (r) | 10 mL | 32 mg/mL (A) |
| 3 mL of dilution A | 3 mL | 16 mg/mL (B) |
| 3 mL of dilution B | 3 mL | 8 mg/mL (C) |
| 3 mL of dilution C | 3 mL | 4 mg/mL (D) |
| 3 mL of dilution D | 3 mL | 2 mg/mL (E) |
| 3 mL of dilution E | 3 mL | 1 mg/mL (F) |
| 3 mL of dilution F | 3 mL | 0.5 mg/mL (G) |
| 3 mL of dilution G | 3 mL | 0.25 mg/mL (H) |
| 3 mL of dilution H | 3 mL | 0.125 mg/mL (I) |
| 3 mL of dilution I | 3 mL | 0.0625 mg/mL (J) |
| 3 mL of dilution J | 3 mL | 0.03 mg/mL (K) |
Powder (methacholine chloride USP)
| TAKE | ADD NaCl 0.9% with 0.9% benzyl alcohol | OBTAIN DILUTION |
| 1280 mg Provocholine (r) | 10 mL | 128 mg/mL (A) |
| 1 mL of dilution A | 7 mL | 16 mg/mL (B) |
| 1 mL of dilution A | 15 mL | 8 mg/mL (C) |
| 4 mL of dilution C | 4 mL | 4 mg/mL (D) |
| 2 mL of dilution C | 6 mL | 2 mg/mL (E) |
| 1 mL of dilution C | 7 mL | 1 mg/mL (F) |
| 1 mL of dilution C | 15 mL | 0.5 mg/mL (G) |
| 4 mL of dilution G | 4 mL | 0.25 mg/mL (H) |
| 2 mL of dilution G | 6 mL | 0.125 mg/mL (I) |
| 1 mL of dilution G | 7 mL | 0.0625 mg/mL (J) |
| 1 mL of dilution G | 15 mL | 0.03 mg/mL (K) |
| TAKE | ADD NaCl 0.9% with 0.9% benzyl alcohol | OBTAIN DILUTION |
| 1600 mg Provocholine (r) | 50 mL | 32 mg/mL (A) |
| 3 mL of dilution A | 3 mL | 16 mg/mL (B) |
| 3 mL of dilution B | 3 mL | 8 mg/mL (C) |
| 3 mL of dilution C | 3 mL | 4 mg/mL (D) |
| 3 mL of dilution D | 3 mL | 2 mg/mL (E) |
| 3 mL of dilution E | 3 mL | 1 mg/mL (F) |
| 3 mL of dilution F | 3 mL | 0.5 mg/mL (G) |
| 3 mL of dilution G | 3 mL | 0.25 mg/mL (H) |
| 3 mL of dilution H | 3 mL | 0.125 mg/mL (I) |
| 3 mL of dilution I | 3 mL | 0.0625 mg/mL (J) |
| TAKE | ADD NaCl 0.9% with 0.9% benzyl alcohol | OBTAIN DILUTION |
| 3 mL of dilution J | 3 mL | 0.03 mg/mL (K) |
| TAKE | ADD Sterile Baseline Solution ( 9 mg per mL sodium chloride USP and 0.66 mg per mL sodium acetate trihydrate USP in water for injection) | OBTAIN DILUTION |
| Sterile Provocholine (r) Solution 16 | 16 mg/mL (A) | |
| 1 mL of dilution A | 3 mL | 4 mg/mL (B) |
| 1 mL of dilution B | 3 mL | 1 mg/mL (C) |
| 1 mL of dilution C | 3 mL | 0.25 mg/mL (D) |
| 1 mL of dilution D | 3 mL | 0.0625 mg/mL (E) |
Note: When preparing serial dilutions using a single 3-mL vial of Sterile Provocholine(r) Solution 16, if needed, a 0.03 mg/mL solution can be prepared by taking 1 mL of the 0.0625 mg/mL dilution and adding 1 mL of the Sterile Baseline Solution for a resulting solution of 0.03 mg/mL.
| TAKE | ADD Sterile Baseline Solution (9 mg per mL sodium chloride USP and 0.66 mg per mL sodium acetate trihydrate USP in water for injection) | OBTAIN DILUTION |
| Sterile Provocholine (r) Solution 16 (2 vials combined) | 16 mg/mL (A) | |
| 3 mL of dilution A | 3 mL | 8 mg/mL (B) |
| 3 mL of dilution B | 3 mL | 4 mg/mL (C) |
| 3 mL of dilution C | 3 mL | 2 mg/mL (D) |
| 3 mL of dilution D | 3 mL | 1 mg/mL (E) |
| 3 mL of dilution E | 3 mL | 0.5 mg/mL (F) |
| TAKE | ADD Sterile Baseline Solution (9 mg per mL sodium chloride USP and 0.66 mg per mL sodium acetate trihydrate USP in water for injection) | OBTAIN DILUTION |
| 3 mL of dilution F | 3 mL | 0.25 mg/mL (G) |
| 3 mL of dilution G | 3 mL | 0.125 mg/mL (H) |
| 3 mL of dilution H | 3 mL | 0.0625 mg/mL (I) |
| 3 mL of dilution I | 3 mL | 0.03 mg/mL (J) |
Administration
General Procedures:
The challenge test must be conducted in a pulmonary function laboratory or clinic, by adequately trained personnel, for safety and accuracy. The FEV1 value should be established before and after diluent or placebo inhalation. After determination of the post-diluent or post-placebo baseline pulmonary function, the predicted value of a positive response is then calculated from the mean before diluent or placebo inhalation. The methacholine challenge is performed by giving a subject increasing serial concentrations of Provocholine(r), after determining baseline FEV1. When using Provocholine(r) Powder, baseline FEV1 is determined with inhaled normal saline control containing 0.9% benzyl alcohol. When using Sterile Provocholine(r) Solution, Sterile Provocholine(r) Solution Plus, baseline FEV1 is determined with the Sterile Placebo Solution. When using Sterile Provocholine(r) Solution 16, baseline FEV1 is determined with the Sterile Baseline Solution. A subject to be challenged must have an FEV1 of at least 70% of the predicted value. A common error giving inaccurate results is caused by not taking a full inspiratory breath prior to baseline FEV1 determination. Consult a physician if the FEV1 falls below 1.5 litres. Do not leave the patient unattended at any time. An inhaled ss-agonist must be administered after a methacholine challenge test with Provocholine(r) to expedite the return of the FEV1 to baseline and to relieve any discomfort of the subject. Most patients revert to normal pulmonary function within 10 to 20 minutes following administration of a ss-agonist. In order to produce interpretable results, it is important to calibrate nebulizers to produce a standard output, and validate the reproducibility of the delivery system. Suitable nebulizers and standard settings are discussed in published sources. Two methods of administration of the methacholine challenge test with Provocholine(r) have been widely used in current clinical practice; the tidal breathing method and the dosimeter method. The tidal breathing technique requires the patient to breathe normally, over a two-minute period, a constantly generated aerosol of Provocholine(r). By contrast, the dosimeter method requires the patient to take five full breaths of Provocholine(r) aerosol generated by an appropriate dosimeter to produce a specific dose per breath. Additional, delivery devices and methods have been described in the literature. Approved manufacturer's instructions should be followed when using these devices. With all techniques, the test is stopped if the FEV1 falls by 20% or more from the mean baseline FEV1. The dose concentration and the percent fall in FEV1 are then used to calculate either the provocative concentration to cause a fall in FEV1 of 20% (PC20), or the provocative dose (PD20).
Tidal Breathing Method:
The following method is based on the use of the Wright nebulizer. If using other nebulizer models, consult published sources on methacholine challenge tests for the appropriate operation of alternate nebulizers.
Using a 3 mL syringe and needle, draw up 2-3 mL of Sterile Placebo Solution, if using Sterile Provocholine(r) Solution, or Sterile Provocholine(r) Solution Plus, or Sterile Baseline Solution if using Sterile Provocholine(r) Solution 16, or use the diluent for Provocholine(r) Powder (0.9% NaCl solution for injection with 0.9% benzyl alcohol as preservative) when using Provocholine(r) Powder and place it in the nebulizer vial. Attach the nebulizer and necessary tubing to an appropriate compressed gas source.
At this time, the subject should be told that subsequent aerosols may produce mild cough, chest tightness or shortness of breath. Tell the subject that if these symptoms become uncomfortable, to remove the face mask or mouthpiece and to stop inhaling the aerosol immediately. Try to avoid suggesting that these symptoms will definitely develop, as suggestion alone can lower the FEV1. Remember that perception of airway narrowing can vary considerably between subjects, making it advisable to watch and listen for other signs such as wheeze and an altered pattern of breathing. Instructions to cease inhaling the aerosol if symptoms become troublesome should be repeated before every dose.
Instruct the patient to relax and breathe the aerosol quietly (tidal breathing) for 2 minutes.
Keeping the nebulizer well away from the patient, adjust the flow meter so that the nebulizer is operating at the calibrated output (0.13 mL/min for the Wright nebulizer).
Apply a nose clip and place the face mask loosely over the nose and mouth (or the mouthpiece in the mouth). Start the stopwatch immediately. The nebulizer should be kept vertical. The patient should hold the nebulizer so as to avoid warming the solution, and subsequently altering the output.
After exactly two minutes, remove the nebulizer from the patient's mouth, turn off the flow meter, and discard the solution.
Measure the FEV1 30 and 90 seconds after the end of the inhalation. These values may be left at ATPS. If the FEV1 at 90 seconds is the same or lower than that at 30 seconds,
the measurement must be repeated at 3 minutes and, if needed, at 2 minute intervals until the FEV1 starts to rise. To avoid tiring the patient, the FEV1 should only be measured once on each occasion. If it is not technically satisfactory, it should be repeated after 10 seconds. If the FEV1 falls by 20% or more from the mean baseline FEV1 (ATPS) or to less than 1.0 litre, no further inhalations are given. (A physician should be consulted if the FEV1 falls below 1.5 litres.) If the FEV1 has fallen by 16% or more from baseline, it is unwise to give further doses. The PC20 may be extrapolated from the last two points of the dose response curve. For Provocholine(r) Powder, the concentration of the first aerosol of Provocholine(r) is 0.03 mg/mL. Subsequent doses are given at approximately 5-minute intervals in doubling concentrations. (0.0625, 0.125, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0 and 16.0 mg/mL). For Sterile Provocholine(r) Solution or Sterile Provocholine(r) Solution 16 (using 1 vial) the concentration of the first aerosol of Provocholine(r) is 0.0625 mg/mL. Subsequent doses are given at approximately 5-minute intervals in quadrupling concentrations. (0.25, 1.0, 4.0 and 16.0 mg/mL). For the Sterile Provocholine(r) Solution Plus or Sterile Provocholine(r) Solution 16 (using 2 vials), the concentration of the first aerosol of Provocholine(r) is 0.0625 mg/mL. Subsequent doses are given at approximately 5-minute intervals in doubling concentrations. (0.125, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0 and 16.0 mg/mL). In all circumstances above, it is optional to adjust the first aerosol of Provocholine(r) to 0.03 mg/mL (see TABLES 1F and 1G and PREPARATION OF DILUTIONS section). Repeat steps 1 through 8 with each increasing concentration of Provocholine(r) until the FEV1 has fallen by 20% or more from baseline, or the FEV1 is 1.5 litres or less, or the highest concentration has been given. Do not give any further aerosols of Provocholine(r). After the test is completed, give the patient 2 puffs of a ss-agonist. Wait 10 minutes and measure the FEV1 and VC. Patients should not be allowed to leave the laboratory until their FEV1 has returned to within 90% of baseline. After the test, reusable nebulizers should be sterilized according to manufacturer's recommendations. Disposable nebulizers should be discarded appropriately.
Dosimeter Method:
The following method is based on the use of a DeVilbiss jet nebulizer attached to a Rosenthal-French dosimeter operating at 20 psi and a period of 0.6 seconds per actuation. If using other nebulizers or dosimeters, consult manufacturer's instructions and published sources on methacholine inhalation challenge for the appropriate operation of alternate nebulizers and dosimeters. The dosimeter should be calibrated to ensure accurate dose delivery and re-calibrated whenever the length of the tubing is changed. All solutions are delivered from functional residual capacity (FRC) to total lung capacity (TLC). Factors that influence the response to inhalation challenge, and which should be consistent, are nebulizer output and inspiratory time. The FEV1 value should be established before and after diluent or placebo inhalation. After determination of the post-diluent or post-placebo baseline pulmonary function, the predicted value of a positive response is then calculated from the mean before diluent or placebo inhalation. Solution is put in the nebulizer, and the necessary tubing attached to the dosimeter. The aerosol is generated by the compressed air delivered at 20 psi through the nebulizer. The output is controlled by a solenoid valve that is triggered by the inspiration and is kept open for 0.6 seconds. A nose clip is used. The subjects are instructed to inhale slowly from the functional residual capacity (FRC) to total lung capacity (TLC). During the inhalation, the vent of the nebulizer should be kept open. Baseline pulmonary function is established with five inhalations of Sterile Placebo Solution if using Sterile Provocholine(r) Solution, Sterile Provocholine(r) Solution Plus, or Sterile Baseline Solutions is using Sterile Provocholine(r) Solution 16 or use the diluent for Provocholine(r) Powder (0.9% NaCl injection with 0.9% benzyl alcohol as preservative), and the baseline FEV1 noted. A subject to be challenged must have an FEV1 of at least 70% of the predicted value, when tested with the diluent. Spirometry is measured within 5 minutes of the fifth inspiration of placebo solution. At this time, the subject should be told that subsequent aerosols may produce mild cough, chest tightness or shortness of breath. Tell the subject that if these symptoms become uncomfortable, to remove the mouthpiece immediately. Try to avoid suggesting that these symptoms will definitely develop, as suggestion alone can lower the FEV1. Remember that perception of airway narrowing can vary considerably between subjects, making it advisable to watch and listen for other signs such as wheeze and an altered pattern of breathing. Instructions to cease inhaling the aerosol if symptoms become troublesome should be repeated before every step up in concentration. As with the tidal breathing technique, serial concentrations of Provocholine(r) are administered. Five inhalations of each concentration are taken, followed by measurement of FEV1 within 5 minutes of the last inhalation at each dosage. One inhalation unit is defined as one inhalation of a solution of Provocholine(r) containing 1 mg/mL. Because doses are taken in rapid succession, the units are expressed as cumulative units, as shown is Table 2 below.
| Serial Concentration | Number of Breaths | Cumulative Units per Concentration | Total Cumulative Units |
| 0.03 mg/mL * | 5 | 0.15 | 0.15 |
| 0.0625 mg/mL | 5 | 0.3 | 0.45 |
| 0.125 mg/mL | 5 | 0.625 | 1.08 |
| 0.25 mg/mL | 5 | 1.25 | 2.33 |
| 0.5 mg/mL | 5 | 2.5 | 4.83 |
| 1 mg/mL | 5 | 5 | 9.83 |
| 2 mg/mL | 5 | 10 | 19.83 |
| 4 mg/mL | 5 | 20 | 39.83 |
| 8 mg/mL | 5 | 40 | 79.83 |
| 16 mg/mL | 5 | 80 | 159.83 |
* If using Sterile Provocholine(r) Solution, Sterile Provocholine(r) Solution Plus or Sterile Provocholine(r) Solution 16, this concentration can be prepared (See PREPARATION OF DILUTIONS section) If the FEV1 falls by 20% or more from the mean baseline FEV1 (ATPS) or to less than 1.0 litre, no further inhalations are given. (A physician should be consulted if the FEV1 falls below 1.5 litres.) Partial doses (fewer than 5 inhalations) may be given if the FEV1 is between 15% and 20% less than baseline control, in order to protect against an excessive fall in pulmonary function. After the test is completed, give the patient 2 puffs of a ss-agonist. Wait 10 minutes and measure the FEV1. Patients should not be allowed to leave the laboratory until their FEV1 has returned to within 90% of baseline. After the test, reusable nebulizers should be sterilized according to manufacturer's recommendations. Disposable nebulizers should be discarded appropriately.
Shortening the Test Procedure:
Technicians should be well versed on the longer procedure before attempting a shorter version. Shortening the test does run the risk of inadvertently giving the patient too high a dose; always err on the side of safety and give a lower dose when in doubt. If clinical history suggests that the patient may not have asthma or that their asthma is very mild, then the lowest concentration may be omitted, as described below:
Starting Concentrations in Adults
As a guide, the first concentration of Provocholine(r) can be based on the following criteria:
If FEV1/VC >80% AND FEV1 >70% predicted AND FEV1 falls <10% after the diluent or placebo inhalation AND the patient's symptoms are well controlled on the following medications, use these starting concentrations:
Medication Starting Concentration
Inhaled or ingested corticosteroids 0.125 mg/mL * Daily bronchodilators 0.25 mg/mL Occasional bronchodilators (< once/day) 1.0 mg/mL No medications 2.0 mg/mL * *
Use 0.0625 mg/mL when 0.125 mg/mL concentration is not available (i.e. Sterile Provocholine(r) Solution
and when using 1 vial of Sterile Provocholine(r) Solution 16).
* * Use 1.0 mg/mL when 2.0 mg/mL concentration is not available (i.e. Sterile Provocholine(r) Solution and
when using 1 vial of Sterile Provocholine(r) Solution 16). If FEV1/VC <80% OR FEV1 <70% predicted AND FEV1 falls <10% after the diluent or placebo inhalation AND the patient's symptoms are well controlled on the following medications, use these starting concentrations:
Medication Starting Concentration
Inhaled or ingested corticosteroids 0.03 mg/mL * Other or no medications 0.125 mg/mL * * If a patient's FEV1 falls by 10% or more after the diluent or placebo inhalation, or if asthma symptoms do not appear to be well controlled, DO NOT omit any concentrations, and start patient at 0.03 mg/mL *.
If using Sterile Provocholine(r) Solution, Sterile Provocholine(r) Solution Plus or Sterile Provocholine(r)
Solution 16, this concentration can be prepared (See PREPARATION OF DILUTIONS section).
* * Use 0.0625 mg/mL when 0.125 mg/mL concentration is not available (i.e. Sterile Provocholine(r) Solution
and when using 1 vial of Sterile Provocholine(r) Solution 16). Starting Concentrations in Children
If FEV1/VC >80% AND the child's symptoms are well controlled on the following medications, use these starting concentrations:
Medication Starting Concentration
Inhaled or ingested corticosteroids 0.03 mg/mL * Daily or occasional bronchodilators 0.0625 mg/mL No medications 0.25 mg/mL
* If using Sterile Provocholine(r) Solution, Sterile Provocholine(r) Solution Plus or Sterile Provocholine(r)
Solution 16, this concentration can be prepared (see PREPARATION OF DILUTIONS section).
If FEV1/VC <80% OR if asthma symptoms do not appear to be well controlled, DO NOT omit any concentrations, and start patient at 0.03 mg/mL.
Omission of Concentrations
If, after the first concentration of Provocholine(r), there has been no evidence of any significant fall in the FEV1 (less than 5% from mean baseline) and there is NO clinical evidence of any bronchoconstriction (chest tightness, cough or wheezing), the next dose may be omitted. As soon as there is any evidence of symptoms or a fall greater than 5% from mean baseline FEV1, DO NOT omit any further concentrations. If a concentration is omitted, it is important to stress before every subsequent inhalation that the subject should remove the face mask/mouthpiece as soon as they experience any breathing or chest discomfort. The above also applies when using Sterile Provocholine(r) Solution Plus and when using serial dilution preparations using 2 vials of Sterile Provocholine(r) Solution 16 diluted as per Table 1F for use with the tidal breathing or dosimeter method. For Sterile Provocholine(r) Solution product, do not omit any concentrations as this product already follows a quadrupling of concentrations. When using only 1 vial Sterile Provocholine(r) Solution 16 diluted for use with the tidal breathing or dosimeter method, do not omit any concentrations as this product already follows a quadrupling of concentrations. For Sterile Provocholine(r) Solution 16, when used in conjunction with medical devices designed to administer gradually increasing concentrations from a single dose of Provocholine(r); manufacturer's instructions should be followed. It is not recommended to exceed the equivalent of a quadrupling of doses with any delivery system.
Calculation and Interpretation of Results:
Either the provocative concentration or the provocative dose causing a 20% fall in FEV1 (PC20 or PD20) may be calculated as described below:
Calculation of PC20 With either the tidal breathing method or the dosimeter method, airway responsiveness may be expressed as that concentration of Provocholine(r) provoking a fall in FEV1 of 20% (PC20). The percent fall in FEV1 can be calculated using the mean baseline FEV1, as shown below:
% fall in FEV1 = mean baseline FEV1 - lowest FEV1 post-Provocholine(r) x 100
mean baseline FEV1 The percent fall in is then plotted against the rising concentration of Provocholine(r) (log scale). The PC20 is obtained by linear interpolation between the last two points, as shown in Figure 1.
Alternatively, the PC20 may be calculated as follows: PC20 = antilog [log C1 + (log C2 - log C1) (20 - R1)] (R2 - R1) Where: C1 = second last concentration (<20% FEV1 fall) C2 = last concentration (>20% FEV1 fall) R1 = % fall FEV1 after C1 R2 = % fall FEV1 after C2
Calculation of PD20 The FEV1 from the best spirogram at each dose is plotted on semilog paper (see example Figure 2, below) and a dose response curve constructed. The dose is expressed as cumulative units, either moles or breath units, where 1 mg/mL is equal to 0.5 moles or 10 breath units. The curve starts at 100%, and the last data point should be at 80% of saline control or lower. From this curve, the PD20, the provocation dose of agonist necessary for a 20% drop in FEV1, can be interpolated. The PD20 is the measure of the sensitivity to Provocholine(r). Patients who do not respond to five inhalations of Provocholine(r) at the 16 mg/mL concentration can be said to have a negative challenge.
Interpretation of Results
In clinical trials, most asthmatics had a positive response at the 10 mg/mL concentration or less. Results can be interpreted with respect to the presence or absence of asthma only if the initial FEV1/VC is >70%. The cut-off point between normal and increased responsiveness is a PC20 of 8 mg/mL, or a PD20 of 4 cumulative umoles or 80 cumulative breath units. (Figure 3). Increased responsiveness is arbitrarily graded as borderline if between 4 and 8 mg/mL (2 and 4 umoles or 40 and 80 breath units), as mild between 2 and <4 mg/mL (1 and <2 umoles or 20 and 40 breath units), as moderate if between 0.25 and <2 mg/mL (0.125 and <1 umoles or 5 and <20 breath units), and as severe if <0.25 mg/mL (<0.125 umoles or <2.5 breath units). Patients with a PC20 >16 mg/mL (or a PD20 >8 umoles or >160 cumulative breath units) are unlikely to have current symptoms due to asthma. When the PC20 is between 2 and 16 mg/mL, or the PD20 is between 1 and 8 umoles or 20 and 160 cumulative breath units, current symptoms due to asthma are likely to be mild, infrequent or absent. Current symptoms of asthma are usual when the PC20 is <2 mg/mL, or the PD20 is <1 umoles or <20 cumulative breath units. NOTE: When using a single dose automatic provocation device system to administer Provocholine(r), the equivalent of the above values will need to be calculated, as appropriate.
Provocholine(r) (methacholine chloride) is to be administered only by inhalation. When administered orally or by injection, overdosage with Provocholine(r) can result in a syncopal reaction, with cardiac arrest and loss of consciousness. Serious toxic reactions should be treated with 0.5 mg to 1 mg of atropine sulfate, administered IM or IV.
Mechanism of Action
Provocholine(r) (methacholine chloride) is a parasympathomimetic (cholinergic) bronchoconstrictor agent to be administered in solution only, by inhalation, for diagnostic purposes. Methacholine chloride is the ss-methyl homolog of acetylcholine and differs from the latter primarily in its greater duration and selectivity of action. Bronchial smooth muscle contains significant parasympathetic (cholinergic) innervation. Bronchoconstriction occurs when the vagus nerve is stimulated and acetylcholine is released from the nerve endings. Muscle constriction is essentially confined to the local site of release because acetylcholine is rapidly inactivated by acetylcholinesterase. Compared with acetylcholine, methacholine chloride is more slowly hydrolysed by acetylcholinesterase and is almost totally resistant to inactivation by non-specific cholinesterase or pseudocholinesterase. When a solution containing Provocholine(r) is inhaled, subjects with current asthma are more sensitive to methacholine and bronchoconstrict at lower doses than healthy subjects. This difference in response is the pharmacologic basis for the Provocholine(r) inhalation diagnostic challenge. The test is most useful diagnostically when there are current symptoms consistent with asthma and when the forced expiratory volume at one second (FEV1) is normal at >70% predicted. A normal result excludes current asthma (variable airflow limitation), but does not exclude past asthma.
Pharmacodynamics
When there is chronic airflow limitation with an FEV1/VC of <70%, the test can be abnormal due to other pathophysiological causes such as smoker's bronchitis, emphysema or cystic fibrosis. The challenge may also be positive in patients with allergic rhinitis without symptoms of asthma, or in patients who have had or will in the future develop asthma symptoms. Certain drugs can affect the pharmacodynamic response to Provocholine(r) (See Drug-Drug Interactions)
Temperature:
Store unopened vials of Provocholine(r) Powder at room temperature (15deg to 30degC). Store Sterile Provocholine(r) Solution, Sterile Provocholine(r) Solution Plus, Sterile Provocholine(r) Solution 16 and Sterile Baseline Solution between 5deg to 25degC.
Other:
Do not use Sterile Provocholine(r) Solution, Sterile Provocholine(r) Solution Plus, Sterile Provocholine(r) Solution 16 and Sterile Baseline Solution if the solution is discoloured.
Reconstituted Solutions:
Freezing does not affect the stability of dilutions made with Provocholine(r) Powder and 0.9% Sodium Chloride with 0.9% Benzyl Alcohol Provocholine(r) Powder reconstituted with 0.9% NaCl solution for injection with 0.9% benzyl alcohol as preservative, using aseptic technique, may be stored under refrigeration (2deg to 8degC) for up to 2 weeks. Store any dilutions of Sterile Provocholine(r) Solution 16 prepared using Sterile Baseline Solution for the shortest expiry period indicated on the original product vials at 5degto 25degC (except for any 0.03 mg/mL dilutions which should be prepared only before use and discarded immediately after use).
Provocholine(r) is a potent bronchoconstrictor. Do not inhale the powder. Do not handle this material if you have asthma or hay fever. A low resistance filter should be applied to an expiratory port of any dosing apparatus, as necessary, to prevent Provocholine(r) aerosol from being released into the air of the room.
Provocholine(r) Powder:
100 mg - in 20 mL and 50 mL amber glass vials in boxes of 6 and 12 vial
160 mg - in 20 mL amber glass vials in boxes of 6 and 12 vials
320 mg - in 20 mL amber glass vials in boxes of 6 and 12 vials
1280 mg - in 20 mL amber glass vials in boxes of 6 and 12 vials
1600 mg - in 50 mL amber glass vials in boxes of 1 vial
0.9% sodium chloride with 0.9% benzyl alcohol as preservative must be used to reconstitute the powder
Administered via inhalation using a nebulizer
Sterile Provocholine(r) Solution: Each carton contains one 3-mL vial each of five concentrations (0.0625 mg/mL, 0.25 mg/mL, 1 mg/mL, 4mg/mL and 16 mg/mL) and one 3 mL vial of sterile placebo solution (for baseline FEV1 testing). Each 3-mL vial of Sterile Provocholine(r) Solution contains: 0.0625 mg, 0.25 mg, 1 mg, 4 mg or 16 mg per mL methacholine chloride USP, 0.66 mg per mL sodium acetate trihydrate and 9 mg per mL sodium chloride in water for injection, sodium hydroxide and/or acetic acid glacial for pH adjustment. Each vial of Sterile Provocholine(r) Solution has a rubber stopper and a flip off seal. The flip off seals are colour coded to represent each of the five various strengths. Please refer to the table below:
| Strength | Colour |
| 0.0625 mg/mL | White |
| 0.25 mg/mL | Avocado |
| 1 mg/mL | Brown |
| 4 mg/mL | Yellow |
| 16 mg/mL | Red |
The colour of the flip off seal for sterile solution placebo is clear.
Sterile Provocholine(r) Solution Plus: Each carton contains one 3-mL vial each of nine concentrations (0.0625 mg/mL, 0.125 mg/mL, 0.25 mg/mL, 0.5 mg/mL, 1 mg/mL, 2 mg/mL, 4 mg/mL, 8 mg/mL and 16 mg/mL) and one 3 mL vial of sterile placebo solution (for baseline FEV1 testing). Each vial of Sterile Provocholine(r) Solution Plus contains: 0.0625 mg, 0.125 mg, 0.25 mg, 0.5 mg, 1 mg, 2 mg, 4 mg, 8 mg or 16 mg per mL methacholine chloride USP, 0.66 mg per mL sodium acetate trihydrate and 9 mg per mL sodium chloride in water for injection, sodium hydroxide and/or acetic acid glacial for pH adjustment. Each vial of Sterile Provocholine(r) Solution Plus has a rubber stopper and a flip off seal. The flip off seals are colour coded to represent each of the nine various strengths. Please refer to the table below:
| Strength | Colour |
| 0.0625 mg/mL | White |
| 0.125 mg/mL | Cool Green |
| 0.25 mg/mL | Avocado |
| 0.5 mg/mL | Blue |
| 1 mg/mL | Brown |
| 2 mg/mL | Black |
| 4 mg/mL | Yellow |
| 8 mg/mL | Orange |
| 16 mg/mL | Red |
The colour of the flip off seal for sterile solution placebo is clear.
Sterile Provocholine(r) Solution 16: Each 3mL vial of Sterile Provocholine(r) Solution 16 contains: 16 mg per mL methacholine chloride USP, 0.66 mg per mL sodium acetate trihydrate and 9 mg per mL sodium chloride in water for injection, sodium hydroxide and/or acetic acid glacial for pH adjustment. Each vial has a rubber stopper and a red flip off seal, and packaged in individual cartons. Each 3 mL vial of Sterile Baseline Solution to be used with Sterile Provocholine(r) Solution 16 contains: 0.66 mg per mL sodium acetate trihydrate and 9 mg per mL sodium chloride in water for injection. Each vial has a rubber stopper and a clear flip off seal, and packaged in individual cartons.