Simultaneous coadministration of calcium carbonate (1200 mg) and dolutegravir (50 mg single dose) to fasting subjects decreased dolutegravir Cmax, AUC and Cmin by 37%, 39% and 39%, respectively. Simultaneous coadministration to fed subjects increased dolutegravir Cmax, AUC and Cmin by 7%, 9% and 8%, respectively. Coadministration of calcium carbonate 2 h after dolutegravir had no effect on dolutegravir Cmax and decreased dolutegravir AUC and Cmin by 6% and 10%, respectively. Dolutegravir should be administered 2 hours before or 6 hours after taking medications containing polyvalent cations, such as calcium supplements. The US Prescribing information suggests that, alternatively, dolutegravir and calcium supplements can be taken together with food. Medicinal products that reduce dolutegravir exposure (e.g. calcium supplements) should be avoided in the presence of integrase class resistance.