Question: Patient
asked whether her Metformin interacted with an over-the-counter medication she
was taking.
Answer: Based on researching the information in Micromedex, it was found that there was no interaction of concern. To further understand possible over-the-counter medications interactions with Metformin, I read the journal article Drug Interactions of Medications Commonly Used in Diabetes and learned that the major OTC interaction of metformin is cimetidine. Cimetidine causes a 60% increase in peak metformin plasma levels. The incidence of metformin-induced lactic acidosis may reach 0.084 cases per 1000 patient-years, with 50% of the cases being fatal. Other adverse effects associated with metformin are upset stomach, B12 deficiency, and headache.
Source:
Metformin. Drug Interactions. Micromedex
Solutions. Truven Health Analytics, Inc. Greenwood Village, CO.
Available at: http://www.micromedexsolutions.com. Accessed May 22, 2015.
Triplitt, C. "Drug Interactions of Medications
Commonly Used in Diabetes." Diabetes Spectrum (2006):19(4); 202-11.