Methacholine Chloride (1 brand name, 1 dosage form, 1 route)
Available dosage forms: FOR SOLUTION.
Routes of administration: INHALATION.
Brand Names
- PROVOCHOLINE
Boxed Warning
WARNING: SEVERE BRONCHOCONSTRICTION Severe bronchoconstriction can result from Provocholine administration (including the lowest dose). The use of Provocholine is contraindicated in pediatric and adult patients with baseline FEV1 < 60% predicted or adults with FEV1 < 1.5 L. Because of the potential for severe bronchoconstriction, the use of Provocholine in patients with clinically apparent asthma or wheezing is not recommended [ see Warnings and Precautions (5.1)]. Emergency equipment and medication should be immediately available to treat acute respiratory distress. If severe bronchoconstriction occurs, reverse immediately with a rapid-acting inhaled bronchodilator agent (β-agonist) [ see Warnings and Precautions (5.1)]. If baseline spirometry is not performed or is measured inaccurately, the initial FEV1 may be underestimated. In this situation, decreases in FEV1 may not be detected after administration of escalating Provocholine doses, which may result in administration of unnecessary higher doses and an increased risk for excessive bronchoconstriction [ see Warnings and Precautions (5.1)].
Indications and Usage
Provocholine, used in a methacholine challenge test, is indicated for the diagnosis of bronchial airway hyperreactivity in adults and pediatric patients five years of age and older who do not have clinically apparent asthma.
Dosage and Administration
.
Contraindications
Provocholine is contraindicated in patients with: Hypersensitivity to methacholine or other parasympathomimetic agents. Reactions have included rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. Baseline FEV 1< 60% predicted (adults or pediatric patients) or <1.5 L (adults)
Warnings and Precautions
.
Adverse Reactions
The following adverse reactions associated with the use of Provocholine were identified in clinical studies or post marketing reports. Because some of these reactions were reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Respiratory System: Bronchospasm (includes symptoms such as chest tightness, cough or wheezing). Less Common Adverse Reactions: Headache, throat irritation, light-headedness and itching.
Drug Interactions
Beta-Adrenergic Blockers The use of beta-adrenergic blockers may impair reversal of Provocholine-caused bronchoconstriction. Beta-Agonists, Anticholinergics, and Theophylline Beta-agonists, anticholinergics, and theophylline inhibit the response of airways to Provocholine; therefore, hold these drugs before Provocholine use for the following duration: • Short-acting β-agonists (e.g., albuterol): 6 hours • Long-acting β-agonists (e.g., salmeterol): 36 hours • Short-acting anti-cholinergics (e.g., ipratropium): 12 hours • Long-acting anti-cholinergics (e.g., tiotropium): ≥168 hours • Oral theophylline: 12-48 hours Oral or Inhaled Corticosteroids, and Inhaled Cromoglycate Regular use of oral or inhaled corticosteroids and inhaled cromoglycate may acutely decrease bronchial responsiveness to Provocholine. However, these drugs may be continued with Provocholine use.
Mechanism of Action
Methacholine chloride is a cholinergic agonist. Bronchial smooth muscle contains significant parasympathetic (cholinergic) innervation. Methacholine chloride agonizes the muscarinic receptors which eventually induce bronchoconstriction.