Serious side effects from large amounts of niacin

Taking excessive doses of a common vitamin in an attempt to defeat drug screening tests may send the user to the hospital -- or worse.

Researchers from The Children's Hospital of Philadelphia and The University of Pennsylvania reported on two adults and two adolescents who suffered serious side effects from taking large amounts of niacin, also known as vitamin B3, in mistaken attempts to foil urine drug tests.

Both adult patients suffered skin irritation, while both adolescents had potentially life-threatening reactions, including liver toxicity and hypoglycemia (low blood sugar), as well as nausea, vomiting and dizziness. One of the teens also experienced heart palpitations.

All four patients recovered after treatment for the adverse effects. The report appeared online today in the "Annals of Emergency Medicine."

"Testing urine for drugs is becoming increasingly common among employers, government agencies and schools," said study leader Manoj K. Mittal, M.D., a fellow in Emergency Medicine at The Children's Hospital of Philadelphia. "Because niacin is known to affect metabolic processes, there is a completely unfounded notion that it can rapidly clear the body of drugs such as cannabis and cocaine. However, not only is niacin ineffective for this purpose, it is also dangerous when taken in large amounts."

Niacin is easily available as an over-the-counter vitamin supplement. As a vitamin, the recommended daily intake is 15 milligrams, but niacin is available in much larger doses at health food stores. "People often assume niacin is completely safe," said Dr. Mittal. "As a water-soluble vitamin, it is easily excreted from the body. However, the body has its limits, and some of these patients took 300 times the daily recommended dose of niacin." Dr. Mittal added that there is a report in the medical literature of a patient who suffered liver failure, requiring a liver transplant, after taking excessive doses of niacin.

Many Internet sites promote the misconception that niacin can be used to pass urine drug screening tests, Dr. Mittal said. "We hope that our study will alert the general public, emergency medicine physicians and other health care providers to this hazardous practice."

In addition to his position at Children's Hospital, Dr. Mittal is an instructor at the University of Pennsylvania School of Medicine. His co- authors are Kevin C. Osterhoudt, M.D., medical director of the Poison Control Center at Children's Hospital; Todd Florin, M.D.; and Jeanmarie Perrone, M.D.; all of the University of Pennsylvania School of Medicine; and Joao H. Delgado, M.D., of Hartford Hospital in Hartford, Conn.

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