Severe bronchoconstriction can result from methacholine chloride administration (including the lowest dose). Use of methacholine chloride is contraindicated in pediatric and adult patients with baseline FEV1 less than 60% predicted or adults with FEV1 less than 1.5 L. Use of methacholine chloride is not recommended in patients with clinically apparent asthma or wheezing. If severe bronchoconstriction occurs, reverse immediately with a rapid-acting inhaled bronchodilator agent (beta-agonist) .
Commonly used brand name(s)
In the U.S.
Available Dosage Forms:
- Powder for Solution
Therapeutic Class: Diagnostic Agent, Bronchial
Pharmacologic Class: Cholinergic
Uses for methacholine
Methacholine inhalation is used to help your doctor diagnose bronchial airway hyperreactivity or asthma. Methacholine works by narrowing your bronchial airways. The degree of narrowing will be measured by a device called a spirometer. This test is also called the methacholine challenge test.
Methacholine is to be given only under the supervision of your doctor.
Before using methacholine
In deciding to use a diagnostic test, any risks of the test must be weighed against the good it will do. This is a decision you and your doctor will make. Also, other things may affect test results. For this test, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to methacholine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Appropriate studies have not been performed on the relationship of age to the effects of methacholine inhalation in children younger than 5 years of age. Safety and efficacy have not been established.
No information is available on the relationship of age to the effects of methacholine inhalation in geriatric patients.
There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.
Interactions with medicines
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are receiving this diagnostic test, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Receiving this diagnostic test with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Glycopyrronium Tosylate
- Oxitropium Bromide
- Pipenzolate Bromide
Interactions with food/tobacco/alcohol
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.
Other medical problems
The presence of other medical problems may affect the use of this diagnostic test. Make sure you tell your doctor if you have any other medical problems, especially:
- Allergic rhinitis without asthma symptoms or
- Infection (eg, upper respiratory infection, influenza) or
- Lung disease, chronic (eg, COPD, tuberculosis, sarcoidosis, or cystic fibrosis)—Use in patients with these conditions may sometimes cause a false-positive result.
- Aortic aneurysm (bulge in the wall of the main artery of the heart) or
- Heart attack, history of or
- Hypertension (high blood pressure), uncontrolled or
- Stroke, history of—Use with caution. Use is not recommended in patients with these conditions.
- Epilepsy or
- Peptic ulcer disease or
- Thyroid disease or
- Urinary tract blockage or
- Vagotonia (excessive activity of the vagus nerve)—Use with caution. May increase risk for more side effects. Your doctor should only test methacholine in patients with these conditions if benefits outweigh the risks.
Proper use of methacholine
A doctor or other health professional will give you methacholine in the hospital. It is given through oral inhalation using a dosimeter. Your doctor will also use a device, called a spirometer, to check for your lung function.
Precautions while using methacholine
It is very important that your doctor check you or your child's progress closely during treatment with methacholine to see if it is working properly and to check for any unwanted effects.
Methacholine may cause severe bronchoconstriction and should not be used in patients with asthma or with breathing difficulties. Check with your doctor right away if you are having severe cough, difficulty breathing, noisy breathing, or tightness in the chest.
Methacholine may cause mild cough, chest tightness, or trouble with breathing. This is normal and nothing to worry about.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.
Methacholine side effects
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor or nurse immediately if any of the following side effects occur:
Incidence not known
- difficulty breathing
- noisy breathing
- tightness in the chest
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
- throat irritation
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.