What the FDA labels say about taking them together
Cobicistat and ritonavir
Cobicistat's FDA label of February 10, 2026 names ritonavir in its drug interactions section; the ritonavir label PlainMeds reads does not name cobicistat. The cobicistat label: “Use of TYBOST with lopinavir is not recommended because lopinavir is co-formulated with ritonavir.”
Check it at the source: the cobicistat FDA label on DailyMed (effective February 10, 2026, Gilead Sciences, Inc.); the ritonavir FDA label on DailyMed (effective July 23, 2026, AbbVie Inc.).
What does the cobicistat label say about ritonavir?
Cobicistat label, drug interactionsUse of TYBOST with lopinavir is not recommended because lopinavir is co-formulated with ritonavir.
Cobicistat label, warnings and precautionsMonitor serum phosphorus in patients with or at risk for renal impairment. ( 5.2 ) TYBOST in combination with more than one antiretroviral that requires pharmacokinetic enhancement (i.e., two protease inhibitors or elvitegravir in combination with a protease inhibitor) is not recommended. ( 5.4 ) Use with HIV-1 protease inhibitors other than atazanavir or darunavir administered once daily is not recommended. ( 5.4 ) Coadministration with drugs or regimens containing ritonavir is not recommended.
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 ritonavir label say about cobicistat?
Ritonavir's label (effective July 23, 2026) does 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 (Norvir), AbbVie Inc., effective July 23, 2026 (SPL set 2849298e-de6e-47bb-8194-56e075b33fc3), 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 | Ritonavir | |
|---|---|---|
| Labeled for | HIV | HIV |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | n/a | $0.607 per tablet 100 mg tablet |
| Shortage now | A presentation being discontinued | A presentation being discontinued |
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