A Retrospective Study of Clinical Effects of Powdered Caffeine Exposures Reported to Three US Poison Control Centers.

Introduction: Anhydrous caffeine, often sold on the Internet as a powdered caffeine product, is sold as "pure caffeine" to be used as an additive to beverages and has also been used as an ingredient in energy supplement products.

Methods: This is a retrospective multiple-poison center chart review of calls regarding powdered caffeine to poison centers covering Oregon, Alaska, Guam, Washington, and Utah between January 1, 2013 and June 30, 2015.

Results: There were 40 calls to three poison centers over 30 months for powdered caffeine exposure. The majority of patients were over age 19 (52.5 %; 21/40) and male (70 %; 28/40). Sixty percent (24/40) of the patients were symptomatic but only 10 % (4/40) required admission; 52.5 % (21/40) of the patient calls were for inadvertent overdose of powdered caffeine; one patient overdosed in a self-harm attempt.

Discussion: Powdered caffeine calls to three poison centers during a 30-month study period were rare, and severe caffeine toxicity due to exposure was found in few patients. The majority of symptoms were reported after an inadvertent powdered caffeine overdose.

Conclusions: An analysis of calls to three poison centers for powdered caffeine found that exposures were uncommon, but did result in toxicity, and highlighted that the lack of clear dosing instructions on product packaging may place patients at risk of inadvertent overdose.