Propranolol
Mechanism :
Propranolol is a nonselective beta-adrenergic receptor blocking agent possessing no other autonomic nervous system activity. It specifically competes with beta-adrenergic receptor stimulating agents for available receptor sites.
Indication :
- Supraventricular arrhythmias
- Ventricular tachycardia
- Tachyarrhythmia of digitalis-intoxication
- Hypertension
- Prophylaxis of common migraine
- Familial or hereditary essential tremor
- Hyperthyroidism with autonomic symptoms
- Infantile hemangioma (off-label)
- Fallot’s tetralogy (Cyanotic spells)
- Portal hypertension.
Contraindications :
Propranolol is contraindicated in cardiogenic shock, sinus bradycardia and greater than first degree block, bronchial asthma, congestive heart failure unless the failure is secondary to a tachyarrhythmia treatable with Propranolol.
Dosing :
Infantile Hemangioma:
Initially start with 0.6 mg/kg PO twice daily for 2 weeks, followed by increase to 1.1 mg/kg twice daily; after additional 2 weeks, increase to 1.7 mg/kg twice daily maintenance dose.
Hypertension and Portal hypertension:
0.5 mg/kg/day PO in 6-12 hourly divided doses, followed by gradual increase every 5-7 days Range: 2-4 mg/kg/day PO in 12 hourly divided doses. Max: 40-80 mg/day.
Arrhythmias:
0.5-1 mg/kg/day PO in 6-8 hourly divided doses; may be gradually increased every 3-7 days (range: 2-6 mg/kg/day; maximum dose: 16 mg/kg/day or 60 mg/day).
IV:
0.01-0.1 mg/kg over 10 mins; to be repeated every 6-8 hourly as and when required. Max: 1 mg for infants/3 mg for children.
Cyanotic spells:
1 mg/kg/day PO in 6 hourly divided doses; may be increased after a week by 1 mg/kg/day to maximum of 10-15 mg/kg/day in case refractory (keep a gap of 24 hours between dose changes).
Thyrotoxicosis:
1 to 2 mg/kg/day PO, given in divided doses every 6 to 12 hours.
Migraine prophylaxis:
0.6 to 3 mg/kg/day PO given in 2 to 3 divided doses; Max daily dose: 60 mg in <35 kg and 120 mg in >30 kg.
Essential tremors:
0.5 to 1 mg/kg/day PO, given in 3 divided doses. Gradually increase once weekly.
Max: 4 mg/kg/day PO or 60 to 80 mg/day PO in adolescents.
Adverse Effect :
Bradycardia, postural hypotension, precipitation of heart block, intermittent claudication, Raynaud’s phenomena, dizziness, confusion, mood changes, nightmares, hallucinations, paraesthesia, bronchospasm, hypoglycemia, purpura, thrombocytopenia.
Interaction :
Calcium Channel Blockers: Additive effect.
Prostaglandin Synthase Inhibiting Drugs: Decrease the hypotensive effects of beta blockers.
Catecholamine-depleting drugs such as reserpine: Hypotension, marked bradycardia, vertigo, syncopal attacks, or orthostatic hypotension.
Haloperidol: Hypotension and cardiac arrest.
Theophylline: Clearance is reduced.
Cimetidine: Increasing blood levels.
Chlorpromazine: Increased plasma levels of both drugs.
Phenytoin, Phenobarbitone and Rifampin: Accelerate propranolol clearance.
Ethanol: Slows the rate of absorption of propranolol.
Aluminium Hydroxide Gel: Greatly reduces intestinal absorption of propranolol.
Renal Dose :
Dose in Renal Impairment GFR (mL/min)
| 20-50 | Dose as in normal renal function |
| 10-20 | Start with small doses and increase according to response |
| <10 | Start with small doses and increase according to response |
Dose in Patients undergoing Renal Replacement Therapies
| CAPD | Not dialysed. Dose as in GFR<10 mL/min |
| HD | Not dialysed. Dose as in GFR<10 mL/min |
| HDF/High flux | Unknown dialysability. Dose as in GFR<10 mL/min |
| CAV/VVHD | Unknown dialysability. Dose as in GFR=10–20 mL/min |
Hepatic Dose :
Hepatic impairment increases systemic exposure to propranolol. Use with caution.