How does dolutegravir sodium (Tivicay) affect metformin exposure?

In adult interaction studies, dolutegravir sodium (Tivicay) 50 mg once daily increased metformin AUC by 79% and Cmax by 66%, versus 145% and 111% with 50 mg twice daily; consider metformin dose adjustment when starting or stopping coadministration and in moderate renal impairment because increased concentrations raise lactic acidosis risk.