Emergency treatment of hypertension
Adult: 20 mg injected slowly for at least 2 min, followed by 40-80 mg dose every 10 min, if necessary up to 300 mg. Patient should remain supine during and 3 hr after the procedure.
Intravenous
Hypotensive anaesthesia
Adult: Initially, 10-20 mg, increase at 5-10 mg increments if satisfactory hypotension is not achieved after 5 min. Administer higher initial doses if halothane anaesth is not used.
Intravenous
Hypertension after myocardial infarction
Adult: Initiate infusion at a rate of 15 mg/hr, then increase gradually until a favourable response is obtained or a dose of 120 mg/hr is reached.
Intravenous
Hypertension in pregnancy
Adult: Start infusion at a rate of 20 mg/hr, doubled every 30 min until a satisfactory response is achieved or a dose of 160 mg/hr is reached.
Oral
Hypertension
Adult: Initially, 100 mg bid, may increase gradually according to patients response to 200-400 mg bid. Max: 2.4 g/day in 2-4 divided doses.
Elderly: Initially, 50-100 mg bid. Maintenance: 100-200 mg bid.
Elderly: Initially, 50-100 mg bid. Maintenance: 100-200 mg bid.