- Significant acute or chronic medical illness, including unstable angina, recent myocardial infarction, history of congestive heart failure, preexisting hypotension (systolic lower than 110) or orthostatic hypotension (systolic drop greater than 20mmHg after two minutes standing or any drop with dizziness), insulin-dependent diabetes mellitus; chronic renal or hepatic failure, pancreatitis, gout, Meniere's disease, benign positional vertigo, narcolepsy