Adult Dose
Oral
Hypertension
Adult: Monotherapy: Initially, 250 mg bid-tid for 2 days; adjust at intervals of at least 2 days according to response. Maintenance: 500-2,000 mg daily.
Max: 3,000 mg daily. Combination therapy: Initial dose should not exceed 500 mg daily in divided doses.
Elderly: Initially, 125 mg bid; gradually increase according to response. Max: 2,000 mg daily.
Child Dose
Oral
Hypertension
Child: <12 yr Initially, 10 mg/kg or 300 mg/m2 daily in 2-4 divided doses; adjust at intervals of at least 2 days according to response.
Max: 65 mg/kg, 2,000 mg/m2 or 3,000 mg daily, whichever is least.
Precaution
Patient w/ history of haemolytic anaemia, liver disease or depression; parkinsonism, hepatic porphyria. Not intended for the treatment of phaeochromocytoma. Renal or hepatic impairment. Childn, elderly. Pregnancy and lactation. Patient Counselling May impair ability to drive or operate machinery. Monitoring Parameters Monitor BP, blood counts, liver enzymes; direct Coombs' test.
Lactation: distributed in breast milk but not in clinically significant amounts; compatible w/ breastfeeding
Side Effect
Drowsiness, orthostatic hypotension, nausea, headache, weakness, fatigue, decreased libido, impotence, impaired concentration and memory, mild psychoses, depression, disturbed sleep, nightmares, paraesthesias, Bell's palsy, parkinsonism, involuntary choreoathetotic movements, oedema, fluid retention, exacerbation of angina pectoris, bradycardia, syncope, prolonged carotid sinus hypersensitivity, paradoxical HTN, GI disturbances (e.g. nausea, vomiting, diarrhoea, constipation), black/sore tongue, inflamed salivary glands, dry mouth, fever, eosinophilia, liver function disturbances, hepatitis, lupus-like syndrome, rashes, lichenoid and granulomatous eruptions, toxic epidermal necrolysis, flu-like syndrome, nocturia, uraemia, nasal congestion, retroperitoneal fibrosis, hyperprolactinaemia, breast enlargement (including gynaecomastia), galactorrhoea, amenorrhoea.
Rarely, pancreatitis and colitis, immune thrombocytopenia, reversible leucopenia (primarily granulocytopenia).
Potentially Fatal: Hepatic necrosis, haemolytic anaemia, hypersensitivity myocarditis.