Terbutaline Sulphate

# Terbutaline sulphate ## Overview - **Classification**: Beta-2 Adrenergic Agonist (Bronchodilator, Tocolytic) - **Mechanism**: Selectively stimulates beta-2 adrenergic receptors in bronchial smooth muscle, causing relaxation and bronchodilation. Also relaxes uterine smooth muscle. ## Primary Indications 1. **Bronchospasm** - Reversible airway obstruction due to asthma, bronchitis, emphysema. 2. **Preterm Labor** - To inhibit uterine contractions in uncomplicated preterm labor (off-label and limited use). ## Adult Dosing ### Standard Dosing **Bronchospasm** (Oral) - **Dose**: **2.5 mg** - **Frequency**: Every 6-8 hours - **Route**: Oral - **Maximum**: **5 mg** three times daily **Bronchospasm** (Subcutaneous) - **Dose**: **0.25 mg** - **Frequency**: Every 15-30 minutes as needed, total of 2 doses - **Route**: Subcutaneous - **Maximum**: **0.5 mg** - **Note**: Administer with care to patients with cardiovascular disease. **Preterm Labor (Tocolysis)** (Subcutaneous - Off-label, limited use) - **Dose**: **0.25 mg** - **Frequency**: Every 15-20 minutes, up to **3-4 doses** - **Route**: Subcutaneous - **Duration**: Up to 24-48 hours, or until contractions subside. - **Note**: Continuous IV infusion typically follows SC bolus. Not recommended for prolonged use due to serious maternal cardiac events. ### Dose Adjustments - **Renal Impairment**: CrCl <50 mL/min: Consider dose reduction. - **Hepatic Impairment**: No specific guidelines. Use with caution. - **Elderly Patients**: Start with lower doses due to potential increased sensitivity to adverse effects. ## Pediatric Dosing ### Neonates (0-28 days) - Use generally not recommended due to limited safety and efficacy data. - Increased risk of cardiovascular effects. ### Infants (1-12 months) - **Bronchospasm**: **0.05 mg/kg** - **Frequency**: Every 6-8 hours - **Route**: Oral - **Maximum**: **2.5 mg/dose** - **Special Notes**: Use only if clearly indicated, with careful monitoring. ### Children (1-12 years) - **Bronchospasm**: **0.05 - 0.1 mg/kg** - **Frequency**: Every 6-8 hours - **Route**: Oral - **Maximum**: **2.5 mg/dose** initially. Max **5 mg/dose** if tolerated. Max **15 mg/day**. ### Adolescents (13-18 years) - **Bronchospasm**: Approach adult oral dosing. - **Dose**: **2.5 mg** - **Frequency**: Every 6-8 hours - **Route**: Oral - **Maximum**: **5 mg** three times daily. ## Safety Information ### Contraindications - **Absolute**: Hypersensitivity to terbutaline or any component. - **Absolute**: Tocolytic use in pregnant patients with pre-existing maternal heart disease. - **Absolute**: Tocolytic use in patients with uncontrolled hyperthyroidism. - **Relative**: Patients with serious cardiovascular disease. ### Common Adverse Effects - **Very Common (>10%)**: Tremor, nervousness, palpitations, headache. - **Common (1-10%)**: Tachycardia, dizziness, nausea, muscle cramps, anxiety. - **Serious but Rare**: Arrhythmias (e.g., supraventricular tachyarrhythmias, ventricular extrasystoles), myocardial ischemia, pulmonary edema (with tocolysis). ### Key Drug Interactions - **Beta-blockers**: May antagonize bronchodilator effect; avoid concurrent use. - **MAOIs/Tricyclic Antidepressants**: Increase cardiovascular effects; use with extreme caution. - **Diuretics (loop or thiazide)**: Enhanced risk of hypokalemia. - **Other Sympathomimetics**: Increased risk of cardiovascular adverse effects. ## Monitoring & Follow-up - **Before Treatment**: Baseline heart rate, blood pressure, respiratory rate. - **During Treatment**: Monitor for symptom control, heart rate, blood pressure, tremor. - **Clinical Signs**: Watch for worsening bronchospasm, chest pain, irregular heartbeat. ## Clinical Pearls - 💡 **Tip 1**: Oral terbutaline has a slower onset of action than inhaled short-acting beta-agonists. - 💡 **Tip 2**: Subcutaneous route for acute exacerbations or severe cases, use only when inhaled options are not feasible or sufficient. - 💡 **Tip 3**: Educate patients on common side effects like tremor and palpitations, reassuring these often resolve with continued use. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.