Phenoxybenzamine

Hypertension in phaeochromocytoma

Oral Hypertension in phaeochromocytoma Adult: Initially, 10 mg once daily or bid, gradually increased daily by 10 mg increments, according to patient's response. Maintenance: 1-2 mg/kg daily in 2 divided doses. Child: 1-2 mg/kg daily. Elderly: 10 mg daily.

CVA, recovery period (usually 3-4 weeks) after acute MI, conditions where a decrease in blood pressure may be undesirable (e.g. coronary artery disease, stroke).

Patient with heart failure, CHF, cerebrovascular diseases, cerebral or coronary atherosclerosis, respiratory infections. Renal impairment. Elderly. Children. Pregnancy and lactation. Patient Counselling This drug may cause dizziness and drowsiness, if affected, do not drive or operate machinery. Monitoring Parameters Regularly monitor blood pressure especially after each dose adjustment; pulse, orthostatics.

C Pregnancy Category: C Lactation: Not known if excreted into breast milk, discontinue drug or do not nurse

Increased hypotensive and cardiac accelerating effect with stimulators of both α- and β-receptors (e.g. epinephrine).

Frequency Not Defined Orthostatic hypotension Tachycardia Dizziness Drowsiness Fatigue Malaise Sedation Dry mouth Nausea Vomiting Inhibition of ejaculation Miosis Nasal congestion

Phenoxybenzamine covalently binds to alpha-receptors causing long lasting non-competitive inhibition of postganglionic synapses thus blocking the effects of epinephrine and norepinephrine at α1 and α2 receptors causing arterial and venous vasodilation and reflex tachycardia.