What the FDA labels say about taking them together
Cobicistat and tadalafil
Cobicistat's FDA label of February 10, 2026 names tadalafil in its drug interactions section; the tadalafil labels PlainMeds reads (3) do not name cobicistat. The cobicistat label: “… sildenafil-associated adverse reactions. The following dose adjustments are recommended for tadalafil concomitant use: Initiation of tadalafil in adult patients taking TYBOST coadministered with atazanavir or darunavir …”
Check it at the source: the cobicistat FDA label on DailyMed (effective February 10, 2026, Gilead Sciences, Inc.); the tadalafil FDA label on DailyMed (effective June 3, 2026, Eli Lilly and Company).
What does the cobicistat label say about tadalafil?
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 tadalafil label say about cobicistat?
Tadalafil's label (effective June 3, 2026) and its 2 other brand-application labels do not name cobicistat in these sections. A label lists what its studies and reports found; it is not a complete list.
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
| Cobicistat | Tadalafil | |
|---|---|---|
| Labeled for | HIV | Erectile dysfunction, Enlarged prostate (BPH), Pulmonary arterial hypertension |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | n/a | $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