Idiopathic SLE & related diseases. Severe tachycardia & heart failure w/ high cardiac output. Myocardial insufficiency due to mechanical obstruction. Isolated right ventricular heart failure due to pulmonary HTN. Dissecting aortic aneurysm.
Prolonged treatment especially w/ doses >100 mg/day may provoke SLE-like syndrome mainly in slow acetylators. Periodic urine analysis & determination of anti-nuclear factors are recommended. Suspected or confirmed CAD. Recent MI. Renal impairment, hepatic dysfunction, cerebrovascular disease, surgery. Pregnancy & lactation.
BP-lowering effect may be potentiated by concurrent use of anesth, other antihypertensives, minor tranquilizers, TCAs. Decreased antihypertensive effect when used concomitantly w/ sympathomimetics. Administration shortly before or after diazoxide may give rise to marked hypotension.