* Exposure of the new anticoagulant dabigatran (Pradaxa) to atmospheric moisture may contribute to deterioration of the drug and a loss of efficacy.
* Exactly how much efficacy can be lost isn't clear.
* Dabigatran should be stored in its original container, away from moisture, heat, and excessive cold; bottles of dabigatran should be used within 30 days of opening.
Diane S. Aschenbrenner is the course coordinator for undergraduate pharmacology at Johns Hopkins University School of Nursing in Baltimore, MD. She also coordinates Drug Watch: email@example.com.