Methacholine is a drug used to diagnose asthma and other airway disorders, such as COPD. It is a synthetic form of acetylcholine, a neurotransmitter found naturally in the body. When inhaled, methacholine causes constriction of the airway muscles, which can be measured by measuring the person's peak expiratory flow rate. If a person's airway is narrowed by more than 20 percent compared to the baseline, it is a sign that the person may have asthma. Methacholine is also used to evaluate the effectiveness of certain asthma medications, such as bronchodilators.
Methacholine, also known by the trade name Provocholine, is a medication used in the diagnosis of asthma. It is a synthetic choline ester that acts like acetylcholine, a natural neurotransmitter. Methacholine causes the airways in the lungs to constrict, which can be helpful in diagnosing asthma because people with asthma are typically more sensitive to this effect.
- Medical use: Primarily used to diagnose bronchial hyperreactivity, a hallmark of asthma.
- Mechanism of action: Acts as a non-selective muscarinic receptor agonist, causing the airways in the lungs to constrict.
- Administration: Inhaled as a mist.
- Contraindications: Not to be used in patients with recent heart attack, stroke, uncontrolled hypertension, severe airway disease, or aortic aneurysm.
Important to note:
- Methacholine is a prescription medication and should only be used under the supervision of a doctor.
- It can cause side effects such as cough, wheezing, chest tightness, nausea, and vomiting.
- Methacholine is not a treatment for asthma, but rather a diagnostic tool.