Hi there ~ Smoking marijuana has many side effects and among the many side effects is the potential for your substance being laced with other substances that would have more serious side effects. Although there are no studies that show that recreational marijuana use has serious side effects or the use of niacin to flush your system off the weed, there are case reports of marijuana use on a recreational basis causing psychological effects and precipitating depression and psychosis. There is also evidence of other medical problems when the marijuana is dirty i.e. laced with other chemicals and substances. I would encourage you to research more on the ill effects of marijuana on the national institute of health website. Report this to your doctor doing surgery as soon as possible. I hope this helps. Take care and have a lovely day!