What the FDA labels say about taking them together
Enzalutamide and nirmatrelvir/ritonavir
Nirmatrelvir/ritonavir's FDA label of February 19, 2026 names enzalutamide in its contraindications section; the enzalutamide labels PlainMeds reads (2) do not name nirmatrelvir/ritonavir. The nirmatrelvir/ritonavir label: “Co-administration contraindicated due to potential loss of virologic response and possible resistance.”
Check it at the source: the enzalutamide FDA label on DailyMed (effective July 28, 2026, Astellas Pharma US, Inc.); the nirmatrelvir/ritonavir FDA label on DailyMed (effective February 19, 2026, Pfizer Laboratories Div Pfizer Inc).
What does the enzalutamide label say about nirmatrelvir/ritonavir?
Enzalutamide's label (effective July 28, 2026) and its 1 other brand-application label do not name nirmatrelvir/ritonavir in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Xtandi), Astellas Pharma US, Inc., effective July 28, 2026 (SPL set b129fdc9-1d8e-425c-a5a9-8a2ed36dfbdf), via openFDA; the full label on DailyMed
What does the nirmatrelvir/ritonavir label say about enzalutamide?
Nirmatrelvir/ritonavir label, contraindicationsAnticancer drugs: apalutamide, enzalutamide
Nirmatrelvir/ritonavir label, drug interactionsDrug Class: Anticancer drugs; Drugs within Class: apalutamide, enzalutamide; Effect on Concentration: ↓ nirmatrelvir/ritonavir; Clinical Comments: Co-administration contraindicated due to potential loss of virologic response and possible resistance [see ].
Source: FDA drug label (Paxlovid), Pfizer Laboratories Div Pfizer Inc, effective February 19, 2026 (SPL set 8a99d6d6-fd9e-45bb-b1bf-48c7f761232a), 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
| Enzalutamide | Nirmatrelvir/ritonavir | |
|---|---|---|
| Labeled for | Prostate cancer | COVID-19 |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | n/a | $49.24 per unit 300-100 mg dose pack |
| Shortage now | No current entry | 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