Drug Interaction Report

ADJUST DOSING INTERVAL: Concurrent administration of velpatasvir with drugs that elevate gastric pH such as antacids may reduce its gastrointestinal absorption. Velpatasvir exhibits pH-dependent solubility, with increased solubility at lower pH. Drugs that increase gastric pH are expected to decrease the plasma concentration of velpatasvir.

MANAGEMENT: If an antacid is required, the antacid should be taken 4 hours before or 4 hours after administration of sofosbuvir-velpatasvir. The same precaution may be applicable to other drugs with antacid effects.

ADJUST DOSING INTERVAL: Administration with food may increase the absorption of calcium. However, foods high in oxalic acid (spinach or rhubarb), or phytic acid (bran and whole grains) may decrease calcium absorption.

MANAGEMENT: Calcium may be administered with food to increase absorption. Consider withholding calcium administration for at least 2 hours before or after consuming foods high in oxalic acid or phytic acid.