Diagnostic Use Only; Severe Bronchoconstriction

Diagnosic Use

• Methacholine is a bronchoconstrictor agent for diagnostic purposes only and should not be used as a therapeutic agent.
• Provocholine (methacholine) inhalation challenge 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.
• Emergency equipment and medication should be immediately available to treat acute respiratory distress.
• Provocholine (methacholine) should be administered only by inhalation.
• Severe bronchoconstriction and reduction in respiratory function can result from the administration of provocholine. Patients with severe hyper-reactivity of the airways can experience bronchoconstriction at a dosage as low as 0.025 mg/mL (0.125 cumulative units). If severe bronchoconstriction occurs, it should be reversed immediately by the administration of a rapid acting inhaled bronchodilator agent(beta agonist).
• Because of the potential for severe bronchoconstriction, Provocholine challenge should not be performed in any patient with clinically apparent asthma, wheezing, or very low baseline pulmonary function tests (e.g., FEV-1 less than 1 to 1.5 liter or less than 70% of the predicted values). Please consult standard nomograms for predicted values.

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>
• 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 (?-agonist).
• If baseline spirometry is not performed or 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.