Adult metformin ingestions reported to Texas poison control centers, 2000-2006.

Metformin is an oral hypoglycemic agent used in the management of type 2 diabetes mellitus. Limited information exists on adult metformin ingestions reported to poison control centers. The distribution of adult metformin ingestions reported to Texas poison control centers during 2000-2006 was determined for various factors. In addition, triage guidelines for the management of isolated ingestions were drafted. Of 1528 total metformin ingestions, 58% involved coingestants. Of the 264 ingestions of metformin alone, where the final medical outcome was known, dose ingested was reported for 66%. The mean reported dose was 4739 mg (range 500-60,000 mg). Ingestions of < or =2500 mg and >5000 mg reported doses differed with respect to the proportion involving suspected attempted suicide (6% versus 81%), serious final medical outcome (3% versus 19%), and referral to a health care facility (3% versus 83%). Using 5000 mg as a threshold dose for referral to a health care facility, 91% of cases not already at or en route to a health care facility were managed according drafted triage guidelines.