Abacavir and Riociguat: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jun 30, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Riociguat
Abacavir
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. Riociguat (Adempas) is a medicine that relaxes blood vessels to help your heart and lungs. Abacavir (Ziagen) is an HIV medicine. Abacavir can slow down how your body breaks riociguat down, so more riociguat can build up in your blood.
When that happens, you may feel riociguat's effects more strongly, especially low blood pressure, which can cause dizziness, lightheadedness, or headache. The good news is this is manageable. Your care team can watch your blood pressure and adjust your riociguat dose if needed. Keep taking both as prescribed, and let your doctor or pharmacist know if you feel faint or dizzy.
Effect: Abacavir inhibits CYP1A1-mediated metabolism of riociguat, increasing riociguat exposure and the risk of dose-related adverse effects (notably hypotension). Neither agent is activated by this pathway, so the net effect is increased pharmacologic activity of riociguat.
- Direction: Increased riociguat exposure (higher AUC/Cmax).
- Onset: Unspecified.
- Evidence: Probable; severity moderate.
- Management: Monitor blood pressure and for symptomatic hypotension. Reduce the riociguat dose if hypotension occurs; individualize per response. Applies to fixed-dose abacavir/dolutegravir/lamivudine.
What happens
Increased riociguat exposure and an increased risk of riociguat-related adverse reactions
Interaction Deep Dive
When riociguat is given together with the fixed-dose combination of abacavir, dolutegravir, and lamivudine, riociguat exposure may rise because abacavir inhibits CYP1A1, potentially raising the likelihood of adverse reactions linked to riociguat1. Should hypotension develop, a reduction in the riociguat dose may be warranted2.
Why it happens (mechanism)
Inhibition of CYP1A1-mediated riociguat metabolism by abacavir
How to manage this interaction
What your care team may do:
- Monitor your blood pressure more closely, especially when you start or change either medicine.
- Adjust and individualize your riociguat dose if signs of low blood pressure appear.
What you can do:
- Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise.
- Report dizziness, lightheadedness, fainting, or persistent headache to your pharmacist or doctor.
- Rise slowly from sitting or lying down to reduce dizziness.
This is a manageable interaction when your team keeps an eye on your response and tailors your dose.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) Giving a single 0.5 mg dose of riociguat to subjects with HIV-1 infection who were taking fixed-dose abacavir/dolutegravir/lamivudine has been reported to raise riociguat AUC (inf) relative to the riociguat AUC (inf) observed in healthy subjects, owing to inhibition of CYP1A1 by abacavir. The precise extent of the rise in riociguat exposure has not been fully characterized based on results from two studies 12.
Common questions
Can I take Abacavir and Riociguat together?
Abacavir can raise riociguat levels and increase the chance of low blood pressure; keep taking both as prescribed and tell your care team if you feel dizzy or faint so they can adjust your riociguat dose. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Abacavir and Riociguat interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How is the Abacavir and Riociguat interaction managed?
What your care team may do: Monitor your blood pressure more closely, especially when you start or change either medicine. Adjust and individualize your riociguat dose if signs of low blood pressure appear. What you can do: Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise. Report dizziness, lightheadedness, fainting, or persistent headache to your pharmac… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Abacavir or Riociguat 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 anything you'd monitor while I'm on both?
References (2)
- Product Information: TRIUMEQ oral tablets, abacavir, dolutegravir, lamivudine oral tablets. ViiV Healthcare (per FDA), Durham, NC, 2023. DailyMed
- Product Information: ZIAGEN(R) oral tablets, oral solution, abacavir oral tablets, oral solution. ViiV Healthcare (per FDA), Research Triangle Park, NC, 2020. DailyMed
Keep reading about Riociguat
Keep reading about Abacavir
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Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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