Liverpool HIV Interactions

Potential Interaction

Elvitegravir/Cobicistat/ Emtricitabine/Tenofovir-DF (EVG/c/FTC/TDF)

Antacids

Quality of Evidence: Very Low

Summary:

Coadministration with Stribild has not been studied. Elvitegravir plasma concentrations are lower with antacids due to local complexation in the gastrointestinal tract and not to changes in gastric pH. The European SPC recommends to separate Stribild and antacid administration by at least 4 hours, whereas the US Prescribing Information recommends at least 2 hours separation. Simultaneous administration of a magnesium/aluminium-containing antacid and elvitegravir/ritonavir decreased elvitegravir AUC, Cmax and Cmin by 45%, 47% and 41%, respectively. Separating the doses by 2 hours decreased elvitegravir exposure by 10-20%, whereas separating the doses by 4 hours did not affect elvitegravir exposure. Coadministration with antacids containing calcium carbonate has not been studied. Emtricitabine and tenofovir-DF do not interact with antacids.

Description:

Coadministration of a magnesium/aluminium-containing antacid suspension (20 mL single dose) and elvitegravir/ritonavir (50/100 mg single dose) had no effect on elvitegravir AUC, Cmin or Cmax when administered 2 hours apart, but decreased elvitegravir AUC, Cmin and Cmax by 45%, 41% and 47%, respectively when administered simultaneously. Elvitegravir plasma concentrations are lower with antacids due to local complexation in the gastrointestinal tract and not to changes in gastric pH. It is recommended to separate Stribild and antacid administration by at least 4 hours.
Stribild Summary of Product Characteristics, Gilead Sciences International Ltd, November 2021.

Coadministration of antacid (20 ml single dose) was studied with elvitegravir/ritonavir (50/100 mg single dose). Antacid administered 4 hours before elvitegravir/ritonavir decreased elvitegravir Cmax and AUC by 5% and 4%, but increased Cmin by 4% (n=8). Antacid administered 4 hours after elvitegravir/ritonavir decreased elvitegravir Cmax and AUC both by 2%, and had no effect on Cmin (n=10). Antacid administered 2 hours before elvitegravir/ritonavir decreased elvitegravir Cmax, AUC and Cmin by 18%, 15% and 10%, respectively (n=11). Antacid administered 2 hours after elvitegravir/ritonavir decreased elvitegravir Cmax, AUC and Cmin by 21%, 20%, and 20%, respectively (n=10). Separate Stribild and antacid administration by at least 2 hours.

Stribild Prescribing Information, Gilead Sciences Inc, September 2021.

Healthy volunteers received elvitegravir/ritonavir (50/100 mg) alone or with antacid administered simultaneously or 2-4 h before. Simultaneous administration with antacid decreased elvitegravir AUC, Cmax and Cmin by 45%, 47% and 41%, respectively. Separating the doses by 2 hours decreased elvitegravir exposure by 10-20%, whereas separating the doses by 4 hours did not affect elvitegravir exposure. Administration with antacids should be staggered by at least 2 hours.

Pharmacokinetic evaluation of drug interactions with ritonavir-boosted HIV integrase inhibitor GS-9137 (elvitegravir) and acid reducing agents. Ramanathan S et al. 8th International Workshop on Clinical Pharmacology on HIV Therapy, Budapest 2007, abstract 69.

View all available interactions with Elvitegravir/Cobicistat/ Emtricitabine/Tenofovir-DF (EVG/c/FTC/TDF) by clicking here.