What the FDA labels say about taking them together
Cobicistat and vardenafil
Cobicistat's FDA label of February 10, 2026 names vardenafil in its drug interactions section, and vardenafil's label names cobicistat too. The cobicistat label: “… 48 hours, tadalafil at a single dose not exceeding 10 mg in 72 hours, or vardenafil at a single dose not exceeding 2.5 mg in 72 hours can be used with increased monitoring for PDE-5 inhibitor associated adverse events.”
Check it at the source: the cobicistat FDA label on DailyMed (effective February 10, 2026, Gilead Sciences, Inc.); the vardenafil FDA label on DailyMed (effective January 5, 2026, Zydus Pharmaceuticals USA Inc.).
What does the cobicistat label say about vardenafil?
Cobicistat label, drug interactionsConcomitant Drug Class/Drug Name: Phosphodiesterase-5 (PDE-5) Inhibitors: avanafil sildenafil tadalafil vardenafil; Potential Effect ↑ = Increase, ↓ = Decrease, ↔ = No change: ↑ PDE-5 inhibitors; Clinical Comment: Coadministration with avanafil is not recommended because a safe and effective avanafil dosage regimen has not been established. Coadministration with TYBOST coadministered with atazanavir or darunavir may result in an increase in PDE-5 inhibitor associated adverse events, including hypotension, syncope, visual disturbances, and priapism. …
Source: FDA drug label (Tybost), Gilead Sciences, Inc., effective February 10, 2026 (SPL set 3784c35c-e87f-410c-900b-8fd6313c6010), via openFDA; the full label on DailyMed
What does the vardenafil label say about cobicistat?
Vardenafil label, drug interactionsConsequently, it is recommended not to exceed a single 2.5 mg vardenafil dose in a 72-hour period when used in combination with ritonavir. [See Dosage and Administration ( 2.4 ) and Warnings and Precautions ( 5.2 ).] Cobicistat with vardenafil can result in increased plasma concentrations, therefore it is recommended that a single 2.5 mg dose of vardenafil should not be exceeded in a 72 hours period. [See Dosage and Administration ( 2.4 ) and Warnings and Precautions ( 5 ).] Moderate CYP3A4 inhibitors Erythromycin (500 mg t.i.d.) produced a 4-fold increase in vardenafil AUC and a 3-fold increase in C max when coadministered with vardenafil 5 mg in healthy volunteers.
Vardenafil label, warnings and precautionsInteractions with Strong or Moderate CYP3A4 Inhibitors Concomitant administration with strong CYP3A4 inhibitors (such as ritonavir, indinavir, cobicistat, ketoconazole) or moderate CYP3A4 inhibitors (such as erythromycin) increases plasma concentrations of vardenafil.
Source: FDA drug label (VARDENAFIL), Zydus Pharmaceuticals USA Inc., effective January 5, 2026 (SPL set 5876e062-e604-42a7-99c3-5da30b8dac06), 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
| Cobicistat | Vardenafil | |
|---|---|---|
| Labeled for | HIV | Erectile dysfunction |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | n/a | $2.79 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