INDERAL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for INDERAL (INDERAL).
Nonselective beta-adrenergic receptor antagonist; competes with catecholamines for binding at beta-1 and beta-2 receptors, decreasing heart rate, myocardial contractility, and blood pressure.
| Metabolism | Extensively hepatic via CYP2D6 and CYP1A2; also glucuronidation; first-pass metabolism; active metabolite 4-hydroxypropranolol. |
| Excretion | Renal: 96-99% as metabolites (active 4-hydroxypropranolol and conjugates), <1% unchanged. Biliary/fecal: minimal. |
| Half-life | 3-6 hours (terminal). Clinical context: half-life increases with chronic dosing due to saturable hepatic metabolism; in cirrhosis, half-life may be prolonged to 10-23 hours. |
| Protein binding | 90-95% bound primarily to albumin, also α1-acid glycoprotein. |
| Volume of Distribution | 3-4 L/kg (large Vd due to extensive tissue distribution, particularly lung, liver, kidney). |
| Bioavailability | Oral: 30-40% (first-pass metabolism; saturable, increases with dose and chronic dosing). IV: 100%. |
| Onset of Action | Oral: 30 minutes (0.5-1 hour for peak β-blockade). IV: 2-5 minutes. |
| Duration of Action | Oral: 6-12 hours (heart rate reduction persists longer than serum levels). IV: 2-4 hours. |
| Action Class | Beta blocker- Non selective |
| Brand Substitutes | Prograin 20mg Tablet, Nigrain 20mg Tablet, Betagem 20mg Tablet, Signolol 20mg Tablet, Arminol 20mg Tablet |
Hypertension: 40 mg orally twice daily; increase as needed up to 640 mg/day. Angina: 80-320 mg orally daily in divided doses. Migraine prophylaxis: 80 mg orally daily in divided doses; up to 160-240 mg/day. Arrhythmias: 10-30 mg orally 3-4 times daily. IV: 1-3 mg IV bolus at 1 mg/min; may repeat after 2 min.
| Dosage form | TABLET |
| Renal impairment | CrCl <10 mL/min: reduce dose by 50%. Severe renal impairment: avoid or use with caution. No specific guidelines for moderate impairment. |
| Liver impairment | Child-Pugh A: no adjustment needed. Child-Pugh B: reduce dose by 50%. Child-Pugh C: avoid use or reduce dose by 75% with close monitoring. |
| Pediatric use | Hypertension: 0.5-1 mg/kg/day orally in divided doses; max 60 mg/day. Arrhythmias: 0.5-1 mg/kg/day; IV: 0.01-0.15 mg/kg IV over 10 min. Migraine: 2-3 mg/kg/day in divided doses; max 240 mg/day. |
| Geriatric use | Start at low end of dosing range (e.g., 20 mg twice daily for hypertension). Titrate slowly. Monitor for bradycardia, hypotension, and CNS effects. Use with caution in patients with impaired renal or hepatic function. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for INDERAL (INDERAL).
| Breastfeeding | Propranolol is excreted into human breast milk in small amounts. Estimated infant dose is approximately 0.1% of maternal weight-adjusted dose. M/P ratio: approximately 0.5. At therapeutic maternal doses, adverse effects in breastfed infants are unlikely, but monitor for signs of beta-blockade (e.g., bradycardia, hypotension). |
| Teratogenic Risk | During the first trimester, limited data suggest a possible increased risk of congenital anomalies (e.g., cardiovascular defects) based on some observational studies; however, absolute risk remains low. Second and third trimester: exposure may cause fetal bradycardia, hypoglycemia, respiratory depression, and intrauterine growth restriction (IUGR). Prolonged use near delivery may result in neonatal beta-blockade effects (bradycardia, hypotension). |
■ FDA Black Box Warning
Abrupt discontinuation may exacerbate angina and increase risk of myocardial infarction; taper dose over 1-2 weeks.
| Serious Effects |
Absolute: cardiogenic shock, sinus bradycardia, heart block greater than first degree, bronchial asthma, overt heart failure. Relative: COPD, Raynaud's phenomenon, psychiatric disorders, concomitant MAOIs.
| Precautions | May mask signs of hypoglycemia and thyrotoxicosis; caution in heart failure, bronchospastic disease, diabetes, and peripheral vascular disease; avoid abrupt withdrawal. |
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| Fetal Monitoring | Monitor maternal heart rate and blood pressure regularly. In pregnancy, assess fetal heart rate and growth via ultrasound. Neonates should be observed for bradycardia, hypoglycemia, and respiratory depression for 48-72 hours after delivery if propranolol was used near term. |
| Fertility Effects | Propranolol does not have known direct adverse effects on fertility. However, by reducing sympathetic outflow, it may theoretically impact sexual function (e.g., erectile dysfunction) in males, but no specific fertility impairment in humans has been established. |