1. severe neurological (e.g., head injury/stroke) conditions, Meniere's disease, narcolepsy, benign positional vertigo, heart disease or unstable angina, history of dysrhythmia/syncope, SBP<110, SBP>160, DBP>110, HR<55, HR>110, irregular heart rhythm, chronic renal or hepatic failure, pancreatitis or insulin-dependent diabetes, or other medical problems requiring immediate attention;