Raltegravir with Aluminum Phosphate Interaction Details
Brand Names Associated with Raltegravir
- Isentress®
- Isentress® HD
- Raltegravir

Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Jan 04, 2024
Interaction Effect
Decreased raltegravir absorption and exposure
Interaction Summary
Coadministration of raltegravir with antacids that contain aluminum or magnesium may reduce raltegravir absorption, resulting in decreased raltegravir plasma concentrations and potential loss of virologic response. In pharmacokinetic studies, the administration of an antacid containing aluminum and magnesium hydroxide given concurrently, 2 hours before, or 2 hours after raltegravir significantly decreased raltegravir exposure. Coadministration or staggered administration of aluminum- or magnesium-containing antacids within 6 hours of raltegravir administration is not recommended.
Severity
Major
Onset
Rapid
Evidence
Established
How To Manage Interaction
Coadministration or staggered administration of aluminum- or magnesium-containing antacids within 6 hours of raltegravir administration is not recommended. When used concomitantly, antacids that contain divalent metal cations may reduce raltegravir absorption, resulting in decreased raltegravir plasma concentrations and potential loss of virologic response.
Mechanism Of Interaction
Chelation of raltegravir by divalent metal cations in the antacid
Literature Reports
A) In pharmacokinetic studies, the Cmax and AUC of patients treated with raltegravir 400 mg twice daily decreased with coadministration of an aluminum and magnesium hydroxide antacid, given either as a single 20 mL dose with raltegravir, 2 hours before raltegravir, or 2 hours after raltegravir. Raltegravir Cmax and AUC decreased by 44% and 49% when given with the antacid (n=25); by 51% and 51% when the antacid was administered 2 hours before raltegravir (n=23); and 22% and 30% when the antacid was administered 2 hours after raltegravir (n=23) .
Raltegravir Overview
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Raltegravir is used along with other medications to treat human immunodeficiency virus (HIV) infection in adults and children who weigh at least 4.5 lbs (2 kg). Raltegravir is in a class of medications called HIV integrase inhibitors. It works by decreasing the amount of HIV in the blood. Although raltegravir 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 life-style changes may decrease the risk of transmitting (spreading) the HIV virus to other people.
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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:
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.