Famotidine with Rilpivirine Interaction Details

Brand Names Associated with Famotidine

Brand Names Associated with Rilpivirine

Medical Content Editor Dr. Brian Staiger, PharmD
Last updated Nov 13, 2023

Interaction Effect

Reduced rilpivirine plasma concentrations and risk of diminished therapeutic effect of rilpivirine

Interaction Summary

Concomitant use of rilpivirine or rilpivirine-containing products with drugs that increase gastric pH, such histamine-2 receptor antagonists, may lead to decreased rilpivirine plasma concentrations and possible loss of virologic response or drug resistance development. During drug interaction studies, a significant decrease in rilpivirine AUC and Cmax was observed in patients administered famotidine 2 hours prior to rilpivirine . If coadministered, rilpivirine should be given 4 hours before or 12 hours following histamine-2 receptor antagonist administration .

Severity

Major

Onset

Rapid

Evidence

Theoretical

How To Manage Interaction

Concomitant administration of rilpivirine or rilpivirine-containing products and a histamine-2 receptor antagonist may result in decreased rilpivirine plasma concentrations. If coadministered, rilpivirine should be given 4 hours before or 12 hours following histamine-2 receptor antagonist administration .

Mechanism Of Interaction

Increased gastric pH

Literature Reports

A) In drug interaction studies, the concomitant administration of famotidine and rilpivirine in healthy subjects or in patients with antiretroviral treatment-naive HIV-1 did not result in significant changes in rilpivirine AUC or Cmax when administered at least 12 hours before or 4 hours following rilpivirine. However, a significant decrease in rilpivirine AUC and Cmax was observed in patients receiving famotidine 2 hours prior to rilpivirine administration. Patients received a single-dose of famotidine 40 mg taken 12 hours before, 2 hours before, or 4 hours after rilpivirine 150 mg. When famotidine was administered 12 hours before, 2 hours before, or 4 hours following rilpivirine administration the mean ratio (rilpivirine plus famotidine/rilpivirine alone) estimate for rilpivirine was 0.91 (90% CI, 0.78 to 1.07), 0.24 (90% CI, 0.2 to 0.28), and 1.13 (90% CI, 1.01 to 1.27), respectively, for AUC. Similarly, the ratio was 0.99 (90% CI, 0.84 to 1.16), 0.15 (90% CI, 0.12 to 0.19), and 1.21 (90% CI, 1.06 to 1.39), respectively, for Cmax. The mean ratio for Cmin was not available .

Famotidine Overview

• Prescription famotidine is used to treat ulcers (sores on the lining of the stomach or small intestine); gastroesophageal reflux disease (GERD, a condition in which backward flow of acid from the stomach causes heartburn and injury of the esophagus [tube that connects the mouth and stomach]); and conditions where the stomach produces too much acid, such as Zollinger-Ellison syndrome (tumors in the pancreas or small intestine that cause increased production of stomach acid). Over-the-counter famotidine is used to prevent and treat heartburn due to acid indigestion and sour stomach caused by eating or drinking certain foods or drinks. Famotidine is in a class of medications called H₂ blockers. It works by decreasing the amount of acid made in the stomach.

Rilpivirine Overview

• Rilpivirine is used along with other medications to treat human immunodeficiency virus type 1 (HIV-1) in certain adults and children 12 years of age and older who weigh at least 77 lb (35 kg) and have not received antiretroviral treatment in the past. It is also used along with cabotegravir (Vocabria) as a short-term treatment of HIV-1 infection in certain adults. Rilpivirine is in a class of medications called non-nucleoside reverse transcriptase inhibitors (NNRTIs). It works by decreasing the amount of HIV in the blood. Although rilpivirine does not cure HIV, it may decrease your chance of developing acquired immunodeficiency syndrome (AIDS) and HIV-related illnesses such as serious infections or cancer. Taking these medications along with practicing safer sex and making other lifestyle changes may decrease the risk of transmitting (spreading) the HIV virus to other people.

Return To Our Drug Interaction Homepage

Feedback, Question Or Comment About This Information?

Definitions

Severity Categories

Contraindicated

These drugs, generally, should not be used together simultaneously due to the high risk of severe adverse effects. Combining these medications can lead to dangerous health outcomes and should be strictly avoided unless otherwise instructed by your provider.

Major

This interaction could result in very serious and potentially life-threatening consequences. If you are taking this drug combination, it is very important to be under close medical supervision to minimize severe side effects and ensure your safety. It may be necessary to change a medication or dosage to prevent harm.

Moderate

This interaction has the potential to worsen your medical condition or alter the effectiveness of your treatment. It's important that you are monitored closely and you potentially may need to make adjustments in your treatment plan or drug dosage to maintain optimal health.

Minor

While this interaction is unlikely to cause significant problems, it could intensify side effects or reduce the effectiveness of one or both medications. Monitoring for changes in symptoms and your condition is recommended, and adjustments may be made if needed to manage any increased or more pronounced side effects.

Onset

Rapid: Onset of drug interaction typically occurs within 24 hours of co-administration.

Delayed: Onset of drug interaction typically occurs more than 24 hours after co-administration.

Evidence

Level of documentation of the interaction.

Established: The interaction is documented and substantiated in peer-reviewed medical literature.

Theoretical: This interaction is not fully supported by current medical evidence or well-documented sources, but it is based on known drug mechanisms, drug effects, and other relevant information.

How To Manage The Interaction

Provides a detailed discussion on how patients and clinicians can approach the identified drug interaction as well as offers guidance on what to expect and strategies to potentially mitigate the effects of the interaction. This may include recommendations on adjusting medication dosages, altering the timing of drug administration, or closely monitoring for specific symptoms.

It's important to note that all medical situations are unique, and management approaches should be tailored to individual circumstances. Patients should always consult their healthcare provider for personalized advice and guidance on managing drug interactions effectively.

Mechanism Of Interaction

The theorized or clinically determined reason (i.e., mechanism) why the drug-drug interaction occurs.

Disclaimer: The information provided on this page is for informational purposes only and should not be considered medical advice. Always consult with a qualified healthcare professional regarding your specific circumstances and medical conditions.

Where Does Our Information Come From?

Information for our drug interactions is compiled from several drug compendia, including:

• Gold Standard Drug Database
• Micromedex
• Lexicomp
• DrugBank

The prescribing information for each drug, as published on DailyMED, is also used. 

Individual drug-drug interaction detail pages contain references specific to that interaction. You can click on the reference number within brackets '[]' to see what reference was utilized.

The information posted is fact-checked by HelloPharmacist clinicians and reviewed quarterly.