Quality of Evidence: Low
Coadministration of metformin (500 mg twice daily) was studied with dolutegravir (50 mg once or twice daily) in 15 subjects. Coadministration with once daily dolutegravir increased metformin Cmax and AUC by 66% and 79%, whereas coadministration with twice daily dolutegravir increased metformin Cmax and AUC by 111% and 145%. A dose adjustment of metformin should be considered when starting and stopping coadministration of dolutegravir with metformin in order to maintain glycaemic control. The US Prescribing Information suggests limiting the total daily dose of metformin to 1000 mg when starting metformin or dolutegravir. Monitoring renal function during coadministration and monitoring blood glucose when starting and stopping coadministration is recommended. As metformin is eliminated renally, patients with moderate renal impairment may be at increased risk for lactic acidosis due to increased metformin concentrations.