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RESPIRATORY SYSTEM › DRUGS FOR OBSTRUCTIVE AIRWAY DISEASES › ADRENERGICS FOR SYSTEMIC USE › Selective beta-2-adrenoreceptor agonists
clenbuterol
R03CC13
Forms & Strengths
- Tablets: 0.02 mg, 0.04 mg
- Syrup: 0.001 mg/mL
- Inhalation aerosol: 0.012 mg/actuation
Adult Dosing
- Bronchospasm: 0.02 mg to 0.04 mg orally twice daily
- Acute administration: 0.02 mg orally as a single dose
Pediatric Dosing
- Children 12 years and older: 0.02 mg orally twice daily
- Children 6-12 years (syrup): 0.01 mg to 0.02 mg twice daily
- Not recommended for children under 6 years due to lack of safety data
Indications
- Adjuvant treatment of reversible bronchospasm in bronchial asthma and chronic obstructive pulmonary disease (COPD)
- Off-label: athletic performance enhancement and weight loss (misuse)
Mechanism of Action
- Selective beta-2 adrenergic receptor agonist
- Stimulates adenylate cyclase, increasing intracellular cAMP
- Relaxes bronchial smooth muscle and inhibits release of immediate hypersensitivity mediators
Contraindications
- Hypersensitivity to clenbuterol or sympathomimetic amines
- Hypertrophic obstructive cardiomyopathy (HOCM)
- Tachyarrhythmias
- First trimester of pregnancy
Adverse Reactions
- Tremor (particularly fine tremor of the hands)
- Palpitations and tachycardia
- Muscle cramps
- Nervousness, anxiety, and restlessness
- Headache
- Hypokalemia (with high doses)
Drug Interactions
- Beta-blockers antagonize the bronchodilatory and therapeutic effects
- Other sympathomimetic agents increase the risk of cardiovascular adverse effects
- Monoamine oxidase inhibitors (MAOIs) and tricyclic antidepressants potentiate vascular effects
- Potassium-depleting diuretics increase risk of severe hypokalemia
Curated Content: Needs Vetting Before Put to Clinical Use