Propranolol Tablets

Mechanism

Propranolol blocks beta-1 and beta-2 adrenergic receptors, leading to decreased heart rate, reduced cardiac output, and inhibition of renin release. This results in lower blood pressure and reduced oxygen demand of the heart.

Pharmacokinetics

• Absorption: Well absorbed orally but undergoes significant first-pass metabolism
• Bioavailability: ~25%
• Distribution: Highly lipophilic; crosses blood-brain barrier
• Metabolism: Extensively metabolized in liver
• Elimination: Excreted via urine as metabolites
• Half-life: 3–6 hours

Side Effects

• Bradycardia
• Fatigue
• Dizziness
• Cold extremities
• Sleep disturbances
• Bronchospasm (in susceptible patients)

Contraindication

• Bronchial asthma
• Severe bradycardia
• Heart block greater than first degree
• Cardiogenic shock

Interaction

• Calcium channel blockers (Verapamil, Diltiazem)
• Antiarrhythmic drugs
• Insulin and oral hypoglycemics
• NSAIDs may reduce antihypertensive effect

Warning and Precautions

• Do not stop abruptly (risk of rebound hypertension)
• Use cautiously in diabetic patients
• Monitor heart rate and blood pressure regularly
• Use with caution in liver impairment