What the FDA labels say about taking them together
Famotidine and fosamprenavir
Famotidine's FDA label of February 6, 2026 names fosamprenavir in its drug interactions (prescription label) section, and fosamprenavir's label names famotidine too. The fosamprenavir label: “Use with caution. Fosamprenavir may be less effective due to decreased amprenavir plasma concentrations.”
Check it at the source: the famotidine FDA label on DailyMed (effective February 6, 2026, Kenvue Brands LLC); the fosamprenavir FDA label on DailyMed (effective September 15, 2023, Mylan Pharmaceuticals Inc.).
What does the famotidine label say about fosamprenavir?
Famotidine label, drug interactions (prescription label)Concomitant administration of famotidine with dasatinib, delavirdine mesylate, cefditoren, and fosamprenavir is not recommended.
Source: FDA drug label (Pepcid AC Original Strength), Kenvue Brands LLC, effective February 6, 2026 (SPL set 54f4086f-e443-4e7e-8c7e-94e152e1c256), via openFDA; the full label on DailyMed
What does the fosamprenavir label say about famotidine?
Fosamprenavir label, drug interactionsConcomitant Drug Class/Drug Name: Histamine H 2 -receptor antagonists: Cimetidine, famotidine, nizatidine, ranitidine; Effect on Concentration of Amprenavir or Concomitant Drug: Fosamprenavir: ↓ Amprenavir Fosamprenavir/ ritonavir: Interaction not evaluated; Clinical Comment: Use with caution. Fosamprenavir may be less effective due to decreased amprenavir plasma concentrations.
Source: FDA drug label (Fosamprenavir Calcium), Mylan Pharmaceuticals Inc., effective September 15, 2023 (SPL set 3a1424d8-844c-4e24-9ebd-b2c2b61b61a3), 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
| Famotidine | Fosamprenavir | |
|---|---|---|
| Labeled for | Acid reflux and ulcers | HIV |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.0289 per tablet 20 mg tablet | n/a |
| 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