What the FDA labels say about taking them together
Ritonavir and tadalafil
Ritonavir's FDA label of July 23, 2026 names tadalafil in its drug interactions section, and tadalafil's label names ritonavir too. The ritonavir label: “… established. Particular caution should be used when prescribing sildenafil, tadalafil or vardenafil in patients receiving ritonavir. Coadministration of ritonavir with these drugs may result in an increase in PDE5 …”
Check it at the source: the ritonavir FDA label on DailyMed (effective July 23, 2026, AbbVie Inc.); the tadalafil FDA label on DailyMed (effective June 3, 2026, Eli Lilly and Company).
What does the ritonavir label say about tadalafil?
Ritonavir label, drug interactionsConcomitant Drug Class/Drug Name: PDE5 Inhibitors: avanafil sildenafil, tadalafil, vardenafil; Effect on Concentration of Ritonavir or Concomitant Drug: ↑ avanafil ↑ sildenafil ↑ tadalafil ↑ vardenafil; Clinical Comment: Sildenafil when used for the treatment of pulmonary arterial hypertension (Revatio ®) is contraindicated due to the potential for sildenafil-associated adverse events, including visual abnormalities, hypotension, prolonged erection, and syncope [see Contraindications () ]. Do not use ritonavir with avanafil because a safe and effective avanafil dosage regimen has not been established. …
Source: FDA drug label (Norvir), AbbVie Inc., effective July 23, 2026 (SPL set 2849298e-de6e-47bb-8194-56e075b33fc3), via openFDA; the full label on DailyMed
What does the tadalafil label say about ritonavir?
Tadalafil label, drug interactionsCYP3A4 inhibitors (e.g. ketoconazole, ritonavir) increase CIALIS exposure ( 2.7 , 5.10 , 7.2 ) requiring dose adjustment:
Tadalafil label, warnings and precautionsThe dose of CIALIS for use as needed should be limited to 10 mg no more than once every 72 hours in patients taking potent inhibitors of CYP3A4 such as ritonavir, ketoconazole, and itraconazole [see Drug Interactions ( 7.2 )].
Adcirca label (United Therapeutics Corporation, December 15, 2025), drug interactionsRitonavir initially inhibits and later induces CYP3A, the enzyme involved in the metabolism of tadalafil.
Source: FDA drug label (Adcirca, NDA022332), United Therapeutics Corporation, effective December 15, 2025 (SPL set ff61b237-be8e-461b-8114-78c52a8ad0ae), via openFDA
Source: FDA drug label (Cialis), Eli Lilly and Company, effective June 3, 2026 (SPL set bcd8f8ab-81a2-4891-83db-24a0b0e25895), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Ritonavir | Tadalafil | |
|---|---|---|
| Labeled for | HIV | Erectile dysfunction, Enlarged prostate (BPH), Pulmonary arterial hypertension |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $0.607 per tablet 100 mg tablet | $0.167 per tablet 20 mg tablet |
| Shortage now | A presentation being discontinued | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once