Home Drug Guide Methacholine Chloride

Drug Guide

Generic Name

Methacholine Chloride

Brand Names Provocholine

Classification

Therapeutic: Diagnostic agent for bronchial hyperreactivity

Pharmacological: Cholinergic agonist, parasympathomimetic

FDA Approved Indications

Diagnosis of bronchial airway hyperreactivity in asthma

Mechanism of Action

Methacholine stimulates muscarinic receptors on airway smooth muscle, causing bronchoconstriction. The degree of constriction is measured to assess airway hyperresponsiveness.

Dosage and Administration

Adult: Administer via inhalation using a nebulizer, typically starting with 0.03 mg/mL concentration, increasing as needed under medical supervision.

Pediatric: Similar protocol as adults, with dose adjustments based on clinical response.

Geriatric: Use with caution; monitor for exaggerated bronchoconstriction.

Renal Impairment: No specific adjustments reported, but use caution.

Hepatic Impairment: No specific adjustments reported.

Pharmacokinetics

Absorption: Rapid onset when administered via inhalation.

Distribution: Local effect in lungs; systemic absorption minimal.

Metabolism: Not extensively metabolized; mainly remains in pulmonary tissues.

Excretion: Primarily exhaled through the lungs.

Half Life: Short; effects last minutes after inhalation.

Contraindications

Patients with hypersensitivity to methacholine or other cholinergic drugs.
Patients with active bronchospasm or acute asthma attack.

Precautions

Use with caution in patients with cardiac disease, increased bronchial hyperresponsiveness, or recent thoracic surgery.

Adverse Reactions - Common

Bronchospasm (Uncommon)
Cough, throat irritation (Common)

Adverse Reactions - Serious

Severe bronchospasm leading to airflow obstruction (Rare)
Cardiovascular reactions (e.g., arrhythmias) during testing (Rare)

Drug-Drug Interactions

Other cholinergic agents may enhance bronchoconstriction.

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Assess baseline lung function and previous response to bronchoprovocation testing.

Diagnoses:

Ineffective airway clearance
Anxiety related to breathing difficulty

Implementation: Administer methacholine via nebulizer under continuous medical supervision, monitor patient response closely.

Evaluation: Monitor for bronchospasm or adverse effects during testing; discontinue if severe reactions occur.

Patient/Family Teaching

Inform patient about the purpose of the test.
Advise on reporting any chest tightness, discomfort, or breathing difficulty during testing.

Special Considerations

Black Box Warnings:

None.

Genetic Factors: None noted.

Lab Test Interference: None known.

Overdose Management

Signs/Symptoms: Excessive bronchoconstriction, severe airflow limitation.

Treatment: Immediate administration of bronchodilators (e.g., inhaled beta-agonists), provide supportive care, and prepare for emergency interventions if needed.

Storage and Handling

Storage: Store at controlled room temperature, away from moisture and light.

Stability: Stable until expiration date on package.