How do H2 receptor antagonists and protease inhibitors (PIs) interact?

Updated: Jan 15, 2019
  • Author: Jason F Okulicz, MD, FACP, FIDSA; Chief Editor: Michelle R Salvaggio, MD, FACP  more...
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H2 receptor antagonists include cimetidine, famotidine, nizatidine, and ranitidine.

H2 receptor antagonists can potentially decrease the drug concentration of RTV-boosted PI; doses should not exceed a dose equivalent of famotidine 40 mg BID in antiretroviral therapy (ART)–naive patients or 20 mg BID in ART-experienced patients.

ATV 300 mg plus RTV 100 mg can be given simultaneously with, and/or more than 10 hours after, the H2 receptor antagonist.

If using tenofovir (TDF) and an H2 receptor antagonist in ART-experienced patients, use ATV 400 mg plus RTV 100 mg.

There is no significant effect between H2 receptor antagonists and DRV/RTV and LPV/RTV.

If PIs such as ATV are used without RTV, they should be administered at least 2 hours before and at least 10 hours after the H2 receptor antagonist; H2 receptor antagonist single dose should not exceed a dose equivalent of famotidine 20 mg or total daily dose equivalent of famotidine 20 mg BID in ART-naive patients.

FPV without RTV should be given at least 2 hours before H2 receptor antagonist if concomitant use is needed; may consider RTV boosting.

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