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Does Ritonavir Interact with Sildenafil Citrate?

Ritonavir and Sildenafil Citrate have a contraindicated drug interaction according to U.S. FDA drug labeling data. 7 DRUG INTERACTIONS • Sildenafil can potentiate the hypotensive effects of nitrates, alpha blockers, and anti-hypertensives ( 4.1 , 5.5 , 7.1 , 7.2 , 7.3 , 12.2 ) • With concomitant use of alpha blockers, initiate sildenafil at 25 mg dose ( 2.3 ) • CYP3A4 inhibitors (e.g., ritonavir, ketoconazole, itraconazole, erythromycin): Increase sildenafil exposure ( 2.4 , 7.4 , 12.3 ) o Ritonavir: Do not exceed a maximum single dose of 25 mg in a 48 hour period ( 2.4 , 5.6 ) o Erythromycin or strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, saquinavir): Consider a starting dose of 25 mg ( 2.4 , 7.4 ) 7.1 Nitrates Administration of sildenafil with nitric oxide donors such as organic nitrates or organic nitrites in any form is contraindicated. 7.4 Ritonavir and other CYP3A4 inhibitors Co-administration of ritonavir, a strong CYP3A4 inhibitor, greatly increased the systemic exposure of sildenafil (11-fold increase in AUC). Patients taking both medications should consult their healthcare provider before starting, stopping, or changing the dosage of either drug. This information is based on official FDA drug labeling sourced from OpenFDA and the NIH National Library of Medicine.

Severity
Contraindicated
Ritonavir Class
Cytochrome P450 3A Inhibitor
Management
Do not take together
Data Source
U.S. FDA via OpenFDA

What To Tell Your Doctor or Pharmacist

If you are taking Ritonavir and your doctor is considering prescribing Sildenafil Citrate (or vice versa), make sure to:

  • Inform your doctor and pharmacist of all current medications, including over-the-counter drugs and supplements
  • Ask whether the benefits of combining these medications outweigh the risks for your specific situation
  • Ask what symptoms to watch for that would indicate the interaction is causing problems
  • Ask about alternative medications that do not interact with your current regimen
  • Ask how frequently you should be monitored while these are co-prescribed
  • Never stop or change either medication without first consulting your healthcare provider
💊 Ritonavir+💊 Sildenafil Citrate(Sildenafil Citrate)

Severity & Interaction Details

⛔
contraindicated
Avoid this combination
FDA labeling lists this pair as contraindicated. The risk outweighs the benefit in nearly all cases.
Severity scale
MinorContra
On record
Yes
Drug A class
Cytochrome P450 3A Inhibitor
Drug B class
—
Source
FDA drug label - sildenafil citrate

What this means in plain English

7 DRUG INTERACTIONS • Sildenafil can potentiate the hypotensive effects of nitrates, alpha blockers, and anti-hypertensives ( 4.1 , 5.5 , 7.1 , 7.2 , 7.3 , 12.2 ) • With concomitant use of alpha blockers, initiate sildenafil at 25 mg dose ( 2.3 ) • CYP3A4 inhibitors (e.g., ritonavir, ketoconazole, itraconazole, erythromycin): Increase sildenafil exposure ( 2.4 , 7.4 , 12.3 ) o Ritonavir: Do not exceed a maximum single dose of 25 mg in a 48 hour period ( 2.4 , 5.6 ) o Erythromycin or strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, saquinavir): Consider a starting dose of 25 mg ( 2.4 , 7.4 ) 7.1 Nitrates Administration of sildenafil with nitric oxide donors such as organic nitrates or organic nitrites in any form is contraindicated. 7.4 Ritonavir and other CYP3A4 inhibitors Co-administration of ritonavir, a strong CYP3A4 inhibitor, greatly increased the systemic exposure of sildenafil (11-fold increase in AUC).

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Data sourced from U.S. FDA drug labeling via openFDA and the NIH National Library of Medicine. For informational purposes only. Always consult your pharmacist or physician.