Depending on the dosage, effects could last as long as 48 hours. Also the method of ingestion is very important. With oral ingestion, the effects last longer as it takes longer for the body to metabolize it. IV or by injection causes immediate effects but tends to metabolize faster as the liver detoxifies it. Snorting it falls somewhere in between.
Hospitilazation and death have been reported, mainly due to erractic EKG, resulting in heart failure.
As litte as .25 grams can trigger symptoms as listed below.
Anorexia, Cravings, Dry mouth, Bruxism, Nystagmus, inability to orgasm, insomnia, elevated heartbeat, temperature flux, heightened BPM & respiration, diarrhea, pupil dilation, intense paranoia, delayed & persistent auditory hallucinations, odored sweat, inability to urinate, strong muscle spasms, severe headache, bruising and dehydration.