Niacin Used in Attempt to Defeat Drug Tests

In a report in today's MMWR, the CDC describes multiple calls to a poison control center by people who experienced adverse reactions after taking large doses of niacin (nicotinic acid or vitamin B3) to try to prevent positive results on urine drug screenings. The most common reactions were tachycardia, flushed skin, rash, nausea, and vomiting.

The claim that niacin can mask the presence of marijuana in urine tests appears on a large number of websites. An editorial note in MMWR states that "no scientific evidence indicates that taking niacin can alter a urine drug test result." The note goes on to warn clinicians that, "with the Internet now a common source of medical information, clinicians can expect to encounter patients with unusual ADRs resulting from nonscientific drug use."