What's considered long-term niacin use? And when do i need to worry about liver toxicity?

I am a former Medical Marijuana patient. I have never known anything to detox marijuana from you. It shows on a blood test. Watch out for flushing (along with itching, and a feeling of itching in your stomach and throat). Use the min. dose of anything - that way, you avoid risks to your body. Employers will piss test you endlessly (I don't blame them for doing a full drug screen, if I were an employer I wouldn't want an employee who was a crack head). My opinion on medical marijuana is different, I would allow it.