Drug Interaction Report

Riociguat and Avanafil: Interaction Details

A pharmacist-reviewed analysis of the Riociguat and Avanafil interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Avanafil

Stendra Stendra®
+

Riociguat

Adempas Adempas®
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
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Interaction severity
Contraindicated
These should generally not be used together.
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.

Of 12 documented Riociguat interactions, 8 are rated contraindicated — including this one.
Worried about symptoms right now? Contact your pharmacist or prescriber, or call Poison Control at 1-800-222-1222 (US). Call 911 for an emergency.
Onset
unspecified
Evidence
theoretical
Severity
Contraindicated

What happens

Increased risk of hypotension

Interaction Deep Dive

Coadministration of riociguat with specific phosphodiesterase (PDE)-5 inhibitors and nonspecific PDE inhibitors is contraindicated. During an exploratory interaction study, coadministration of riociguat and sildenafil resulted in additive hemodynamic effects. Do not administer riociguat within 24 hours of sildenafil. Do not administer riociguat 24 hours before or within 48 hours after tadalafil. Use with other PDE inhibitors is limited1.

Why it happens (mechanism)

Unknown

Literature reports

1 report — tap to read

a) During an exploratory interaction study (n=7), administration of single doses of riociguat 0.5 mg and 1 mg sequentially in patients with pulmonary arterial hypertension (PAH) on stable sildenafil treatment 20 mg 3 times daily resulted in additive hemodynamic effects. Riociguat 1 mg to 2.5 mg 3 times daily in combination with sildenafil 20 mg 3 times daily in patients with PAH resulted in one death potentially associated with study treatment and a high discontinuation rate due to hypotension 2.

Common questions

Can I take Riociguat and Avanafil together?

Increased risk of hypotension Always confirm with your pharmacist or prescriber before making any change.

How serious is the Riociguat and Avanafil interaction?

It is rated contraindicated. These should generally not be used together.

How quickly could this interaction happen?

The documented onset is "unspecified". The timing of this interaction is not well characterized.

How strong is the evidence for this interaction?

The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.

Questions for your pharmacist

  • Does my dose of Riociguat or Avanafil 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 (2)

  1. Product Information: ADEMPAS oral tablets, riociguat oral tablets. Bayer HealthCare Pharmaceuticals Inc. (per FDA), Whippany, NJ, 2017. DailyMed
  2. Product Information: Adempas oral tablets, riociguat oral tablets. Bayer HealthCare Pharmaceuticals Inc. (per manufacturer), Whippany, NJ, 2013. DailyMed
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Beyond drug–drug

These medications also interact with supplements

Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:

Avanafil + Activated Charcoal American Mistletoe Grapefruit Hawthorn St. John's Wort Acacia Rigidula Adrafinil African Wild Potato + 136 more
Riociguat + Activated Charcoal American Hellebore American Mistletoe Grapefruit St. John's Wort Tyramine Acacia Rigidula Adrafinil + 222 more

major · moderate · minor — check everything you take with our drug–supplement interaction checker.

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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.