METAPROTERENOL SULFATE
| METAPROTERENOL SULFATE (met-a-proe-ter'e-nole) Alupent, Metaprel Classifications: beta-adrenergic agonist; bronchodilator; Therapeutic: bronchodilator Prototype: Albuterol Pregnancy Category: C |
Availability
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
Action
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.
Therapeutic Effect
Bronchodilator; controls bronchospasm in asthmatics.
Uses
Bronchodilator in symptomatic relief of asthma and reversible bronchospasm associated with bronchitis and emphysema.
Unlabeled Uses
Treatment and prophylaxis of heart block and to avert progress of premature labor (tocolytic action).
Contraindications
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.
Cautious Use
Older adults; hypertension, cardiovascular disorders including coronary artery disease, cardiac arrhythmias, QT prolongation; MAOI therapy; lactation.
Route & Dosage
| Bronchospasm Adult: PO 20 mg q6–8h Metered Dose Inhaler 2–3 inhalations q3–4h (max: 12 inhalations/d) Nebulizer 5–10 inhalations of undiluted 5% solution IPPB 2.5 mL of 0.4–0.6% solution q4–6h Geriatric: PO 10 mg 3–4 times/d, may increase to 20 mg 3–4 times/d Child: PO <2 y, 0.4 mg/kg t.i.d.–q.i.d.; 2–6 y, 1.2–2.6 mg/kg/d in 3–4 divided doses; 6–9 y, 10 mg q6–8h; >9 y, 20 mg q6–8h |
Administration
- 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), headache, fatigue. CV: Tachycardia, hypertension, cardiac arrest, palpitation. GI: 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 are antagonized.Pharmacokinetics
Absorption: 40% of PO doses reach systemic circulation. Onset: Inhaled: 1 min; PO 15 min. Peak: 1 h all routes. Duration: Inhaled: 1–5 h; PO 4 h. Metabolism: In liver. Elimination: In urine.Nursing Implications
Assessment & Drug Effects
- Monitor respiratory status. Auscultate lungs before and after inhalation to determine efficacy of drug in decreasing airway resistance.
- 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.
Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; 
Canadian drug name; 
Prototype drug