Coadministration has not been studied. Ascorbic acid is oxidised to dehydroascorbic acid where some is metabolised to oxalic acid and the inactive ascorbate-2-sulphate. Large doses are rapidly excreted in the urine when in excess of the requirements of the body. A pharmacokinetic interaction is unlikely with vitamin C itself. However, vitamin C can be found in multivitamin preparations. Simultaneous coadministration of a multivitamin preparation decreased dolutegravir exposure by ~33%. Dolutegravir should be administered 2 hours before or 6 hours after medications containing polyvalent cations, such as multivitamin preparations. Medicinal products that reduce dolutegravir exposure (e.g. multivitamins) should be avoided in the presence of integrase class resistance.