Rhabdomyolysis Risk: The Dangers of Tribulus Terrestris, an Over-the-Counter Supplement.

BACKGROUND Over-the-counter (OTC) supplement use is a very common practice within the United States. Supplements are not tightly regulated by the Food and Drug Administration. There are many case reports involving OTC supplement adverse effects and medication interactions, but there remains minimal clinical research regarding these subjects. Rhabdomyolysis is one interaction and adverse effect frequently documented in case reports among a variety of OTC supplements, although, to date, there is no documentation of rhabdomyolysis occurring from an interaction between the supplement Tribulus terrestris and atorvastatin. CASE REPORT A 71-year-old man presented to the Emergency Department in rhabdomyolysis with a mild transaminitis after taking the over-the-counter supplement Tribulus terrestris while on long-term atorvastatin. His rhabdomyolysis peaked at day 4 after cessation of the Tribulus and atorvastatin and aggressive fluid resuscitation with a normal saline bolus at admission followed by a D5 sodium bicarbonate drip later transitioned to a normal saline drip with subsequent down-trending of the creatinine phosphokinase levels. CONCLUSIONS Tribulus terrestris is an herbal supplement used for erectile dysfunction and energy. Recent research suggests it to be a moderate CYP 3A4 inhibitor that plays a significant role in metabolism of statin and many other commonly prescribed medications. This may put patients at increased risk of developing serious adverse effects, including rhabdomyolysis and drug-induced liver injury. Screening patients for over-the-counter supplement use and educating them on the potential risks of their use is extremely important for inpatient and outpatient healthcare professionals to avoid dangerous medication interactions.