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Methacholine Side Effects

Medically reviewed by Last updated on Oct 21, 2022.

Applies to methacholine: inhalation powder for solution, inhalation solution.


Inhalation, oral/nebulization route (Powder for Solution)

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).

Serious side effects of Methacholine

Along with its needed effects, methacholine 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 while taking methacholine:

Incidence not known

  • Cough
  • difficulty breathing
  • noisy breathing
  • tightness in the chest

Other side effects of Methacholine

Some side effects of methacholine 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:

Less common

  • Headache
  • itching
  • lightheadedness
  • throat irritation

For Healthcare Professionals

Applies to methacholine: compounding powder, inhalation powder for reconstitution, inhalation solution.


When administered orally or by injection, this drug is reported to cause nausea, vomiting, substernal pain or pressure, hypotension, fainting, and transient complete heart block. Overdosage with this drug, when administered orally or by injection, can result in a syncopal reaction with cardiac arrest and loss of consciousness. This drug should be administered only by inhalation.[Ref]

Nervous system

Very rare (less than 0.01%): Headache, lightheadedness[Ref]


Very rare (less than 0.01%): Itching[Ref]


Very rare (less than 0.01%): Throat irritation[Ref]


1. "Product Information. Provocholine (methacholine)." Methapharm Inc (2002):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.