Discontinue if allergic reaction occurs or in case of headache, confusion or nausea. Caution in patients w/ CV, immune, liver or chronic kidney disease, hormonal or seizure disorders, asthma, depression, diabetes, low blood sugar or migraines; sleeplessness that persists for >1 mth (chronic insomnia). Avoid taking w/ alcohol or products that increase drowsiness. Do not drive or use machinery for 5 hr after taking melatonin.