What the FDA labels say about taking them together
Fentanyl and ritonavir
Fentanyl's FDA label of March 6, 2026 names ritonavir in its drug interactions section, and ritonavir's label names fentanyl too. The ritonavir label: “… Careful monitoring of therapeutic and adverse effects is recommended when fentanyl is concomitantly administered with NORVIR.”
Check it at the source: the fentanyl FDA label on DailyMed (effective March 6, 2026, Hikma Pharmaceuticals USA Inc.); the ritonavir FDA label on DailyMed (effective July 23, 2026, AbbVie Inc.).
What does the fentanyl label say about ritonavir?
Fentanyl label, drug interactionsInhibitors of CYP3A4 Clinical Impact: The concomitant use of Fentanyl Citrate Injection and CYP3A4 inhibitors can increase the plasma concentration of fentanyl, resulting in increased or prolonged opioid effects, particularly when an inhibitor is added after a stable dose of Fentanyl Citrate Injection is achieved. … antibiotics (e.g., erythromycin), azole-antifungal agents (e.g., ketoconazole), protease inhibitors (e.g., ritonavir), grapefruit juice
Fentanyl label, warnings and precautionsUse or Discontinuation of Cytochrome P450 3A4 Inhibitors and Inducers Concomitant use of Fentanyl Citrate Injection with a CYP3A4 inhibitor, such as macrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g., ketoconazole), and protease inhibitors (e.g., ritonavir), may increase plasma concentrations of fentanyl and prolong opioid adverse reactions, which may exacerbate respiratory depression [see Warnings and Precautions (5.2) ], particularly when an inhibitor is added after a stable dose of Fentanyl Citrate Injection is achieved.
Fentanyl Citrate label (Hospira, Inc., August 24, 2026), drug interactionsMacrolide antibiotics (e.g., erythromycin), azole-antifungal agents (e.g., ketoconazole), protease inhibitors (e.g., ritonavir), grapefruit juice.
Source: FDA drug label (Fentanyl Citrate, NDA019115), Hospira, Inc., effective August 24, 2026 (SPL set bfa8018a-4cbc-434b-e09e-782872b0340a), via openFDA
Source: FDA drug label (Fentanyl Citrate), Hikma Pharmaceuticals USA Inc., effective March 6, 2026 (SPL set ce5db1c2-feb1-4ad2-847a-d02e865bd47e), via openFDA; the full label on DailyMed
What does the ritonavir label say about fentanyl?
Ritonavir label, drug interactionsConcomitant Drug Class/Drug Name: Analgesics, Opioid: tramadol, propoxyphene, methadone, fentanyl; Effect on Concentration of Ritonavir or Concomitant Drug: ↑ analgesics ↓ methadone ↑ fentanyl; Clinical Comment: A dose decrease may be needed for these drugs when co-administered with ritonavir. Dosage increase of methadone may be considered. Careful monitoring of therapeutic and adverse effects (including potentially fatal respiratory depression) is recommended when fentanyl is concomitantly administered with NORVIR.
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
| Fentanyl | Ritonavir | |
|---|---|---|
| Labeled for | Pain | HIV |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $1.79 per mL 100 mcg/2 mL vial | $0.607 per tablet 100 mg tablet |
| Shortage now | In shortage | 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