Classifications: beta-adrenergic agonist; bronchodilator; Therapeutic: bronchodilator
Pregnancy Category: C
10 mg, 20 mg tablet; 10 mg/5 mL syrup; 75 mg, 150 mg metered dose inhaler; 0.4%, 0.6%, 5% solution for inhalation
Potent synthetic beta-adrenergic agonist that acts selectively on beta2-adrenergic receptors to relax smooth muscle of bronchi, uterus, and blood vessels supplying skeletal muscles.
Bronchodilator; controls bronchospasm in asthmatics.
Bronchodilator in symptomatic relief of asthma and reversible bronchospasm associated with bronchitis and emphysema.
Treatment and prophylaxis of heart block and to avert progress of premature labor (tocolytic action).
Sensitivity to other sympathomimetic agents; seizure disorders, seizures; diabetes mellitus; hyperthyroidism; pregnancy
(category C). Safety in children <12 y (for aerosol use) and children <6 y (tablets) is not established.
Older adults; hypertension, cardiovascular disorders including coronary artery disease, cardiac arrhythmias, QT prolongation;
MAOI therapy; lactation.
Route & Dosage
Adult: PO 20 mg q68h Metered Dose Inhaler 23 inhalations q34h (max: 12 inhalations/d) Nebulizer 510 inhalations of undiluted 5% solution IPPB 2.5 mL of 0.40.6% solution q46h
Geriatric: PO 10 mg 34 times/d, may increase to 20 mg 34 times/d
Child: PO <2 y, 0.4 mg/kg t.i.d.q.i.d.; 26 y, 1.22.6 mg/kg/d in 34 divided doses; 69 y, 10 mg q68h; >9 y, 20 mg q68h
- Note: Patient may use tablets and aerosol concomitantly.
- Give with food to reduce GI distress.
- Instruct patient to shake metered dose aerosol container, exhale through nose as completely as possible, administer aerosol
while inhaling deeply through mouth, and to hold breath about 10 sec before exhaling slowly. Administer second inhalation
10 min after first.
- Store all forms at 15°30° C (59°86° F); protect from light and heat.
Adverse Effects (≥1%)CNS:
Nervousness, weakness, drowsiness, tremor (particularly after PO administration),
. CV: Tachycardia,
hypertension, cardiac arrest,
Nausea, vomiting, bad taste. Urogenital:
Occasional difficulty in micturition and muscle cramps. Respiratory:
Throat irritation, cough, exacerbation of asthma
Interactions Drug: Epinephrine,
other sympathomimetic bronchodilators
may compound effects of metaproterenol; mao inhibitors
, tricyclic antidepressants
potentiate action of metaproterenol on vascular system; the effects of both metaproterenol and beta-adrenergic blockers
40% of PO doses reach systemic circulation. Onset:
Inhaled: 1 min; PO 15 min. Peak:
1 h all routes. Duration:
Inhaled: 15 h; PO 4 h. Metabolism:
In liver. Elimination:
Assessment & Drug Effects
- Monitor respiratory status. Auscultate lungs before and after inhalation to determine efficacy of drug in decreasing airway
- Monitor cardiac status. Report tachycardia and hypotension.
Patient & Family Education
- Report failure to respond to usual dose. Drug may have shorter duration of action after long-term use.
- Do not increase dose or frequency unless ordered by physician; there is the possibility of serious adverse effects.
- Anticipate tremor as a possible adverse effect.