Omeprazole and Indinavir: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 2, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Indinavir
No brand names on recordOmeprazole
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
Here's what's going on. Indinavir is an HIV medicine that needs an acidic (low pH) stomach to be absorbed well. Omeprazole (Prilosec) works by cutting down stomach acid. So when you take them together, your body absorbs less indinavir, and that means less of it gets into your blood to fight HIV.
That's the concern here: not more side effects, but the HIV medicine possibly working less than it should. The good news is your care team can manage this. Please don't stop or change either medicine on your own. Just talk with your doctor or pharmacist, who can adjust your plan and keep your treatment on track.
Effect: Reduced indinavir exposure and potential loss of antiviral efficacy.
Mechanism: Omeprazole raises gastric pH, and indinavir absorption is pH-dependent, so its oral bioavailability falls. This is a PK interaction (reduced AUC), not enzyme-based. Neither agent's active form is a prodrug issue here.
- Direction: Decreased indinavir AUC/Cmax.
- Onset: Delayed. Evidence: Established (PK study).
- Magnitude: Significant AUC reduction documented.
Management: Use caution with concurrent use. If coadministration is required, adding ritonavir (pharmacokinetic booster) is documented to raise indinavir exposure. Monitor virologic response.
What happens
Reduced indinavir exposure with reduced efficacy
Interaction Deep Dive
When indinavir is given together with omeprazole, the bioavailability and systemic exposure of indinavir can drop considerably, which may lead to a loss of indinavir's therapeutic effect. In a pharmacokinetic analysis, the indinavir AUC fell markedly during coadministration with omeprazole, whereas adding ritonavir 200 mg produced a higher indinavir AUC. The proposed mechanism is that omeprazole reduces the pH-dependent bioavailability of indinavir. Concurrent use of omeprazole with indinavir warrants caution. Should combined therapy be necessary, incorporating ritonavir into the regimen may be considered as a way to raise indinavir exposure1.
Why it happens (mechanism)
Decrease in pH-dependent indinavir bioavailability by omeprazole
How to manage this interaction
Keep taking both medicines as prescribed unless your care team tells you otherwise. The main issue is that omeprazole can lower how much indinavir your body absorbs, which could make the HIV medicine less effective.
- Your care team may boost indinavir levels by adding ritonavir, which is documented to raise indinavir exposure.
- They may monitor your treatment response more closely.
- Ask your pharmacist or prescriber before starting any acid-reducing product, including over-the-counter Prilosec.
The important thing to raise: make sure your prescriber knows you take both, so your regimen can be tailored to keep your HIV treatment working.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) In a prospective, randomized, placebo-controlled, single-dose crossover study (n=14) involving HIV negative patients designed to assess how two separate doses of omeprazole affect indinavir pharmacokinetics, giving omeprazole 20 mg or 40 mg together with indinavir significantly lowered the mean AUC from 30 mg x hr/L (95% confidence interval (CI), 21.9 to 41.1 mg x hr/L) to 19.7 mg x hr/L (95% CI, 14.6 to 26.8 mg x hr/L) or 16 mg x hr/L (95% CI, 11.8 to 21.7 mg x hr/L), respectively (p less than 0.002). Participants were randomly assigned to placebo, omeprazole 20 mg, or omeprazole 40 mg for 7 days, and this was followed by a single dose of indinavir 800 mg either alone or combined with 200 mg of ritonavir. The single-dose pharmacokinetic profile of the 800 mg indinavir dose alone or together with 200 mg of ritonavir was examined. The mean indinavir AUC rose significantly from 30 mg x hr/L (95% CI, 21.9 to 41.1 mg x hr/L) to 46.6 mg x hr/L (95% CI, 34 to 63.8 mg x hr/L) when ritonavir 200 mg was added to indinavir 800 mg given alongside omeprazole 40 mg; mean omeprazole concentrations showed no significant change (p less than 0.02). This elevated indinavir AUC was also significantly higher than the indinavir AUC observed when indinavir was given with and after placebo. No statistically significant change was seen in the Cmax or Tmax of indinavir following omeprazole administration. When ritonavir was added to indinavir, the Cmax of indinavir was not significantly changed, but the Tmax of indinavir was significantly prolonged 1.
Common questions
Can I take Omeprazole and Indinavir together?
Omeprazole can lower indinavir absorption and make the HIV medicine work less well; don't change anything on your own, and tell your care team, who may add ritonavir to boost indinavir or monitor you more closely. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Omeprazole and Indinavir interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How is the Omeprazole and Indinavir interaction managed?
Keep taking both medicines as prescribed unless your care team tells you otherwise. The main issue is that omeprazole can lower how much indinavir your body absorbs, which could make the HIV medicine less effective. Your care team may boost indinavir levels by adding ritonavir, which is documented to raise indinavir exposure. They may monitor your treatment response more closely. Ask your pharmaci… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "established". Well documented — supported by controlled studies or strong clinical data.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Omeprazole or Indinavir need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (1)
- Tappouni HL, Rublein JC, Donovan BJ, et al: Effect of omeprazole on the plasma concentrations of indinavir when administered alone and in combination with ritonavir. Am J Health Syst Pharm 2008; 65(5):422-428. PubMed
Keep reading about Indinavir
Keep reading about Omeprazole
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