Patient asked whether her metformin interacted with an
over-the-counter medication she was taking.
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 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.
References
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.
