What the FDA labels say about taking them together
Lansoprazole and nelfinavir
Lansoprazole's FDA label of June 24, 2025 names nelfinavir in its drug interactions (prescription label) section; nelfinavir's label does not name lansoprazole itself but warns about its class (Proton pump inhibitors (PPIs)). The lansoprazole label: “The effect of PPIs on antiretroviral drugs is variable. The clinical importance and the mechanisms behind these interactions are not always known. …”
Check it at the source: the lansoprazole FDA label on DailyMed (effective June 24, 2025, L. Perrigo Company); the nelfinavir FDA label on DailyMed (effective December 11, 2025, AGOURON).
What does the lansoprazole label say about nelfinavir?
Lansoprazole label, drug interactions (prescription label)Antiretrovirals Clinical Impact: The effect of PPIs on antiretroviral drugs is variable. The clinical importance and the mechanisms behind these interactions are not always known. Decreased exposure of some antiretroviral drugs (…) when used concomitantly with lansoprazole may reduce antiviral effect and promote the development of drug resistance. … Intervention: Rilpivirine-containing products: Concomitant use with PREVACID or PREVACID SoluTab is contraindicated [see ]. See prescribing information. Atazanavir: See prescribing information for atazanavir for dosing information. Nelfinavir: Avoid concomitant use with PREVACID or PREVACID SoluTab. …
Source: FDA drug label (Prevacid 24 HR), L. Perrigo Company, effective June 24, 2025 (SPL set 205c9c1e-b422-4e86-a4b0-714b608adc19), via openFDA; the full label on DailyMed
What does the nelfinavir label say about lansoprazole?
Nelfinavir's label does not name lansoprazole itself; it warns about its class (Proton pump inhibitors (PPIs)):
Nelfinavir label, drug interactionsPROTON PUMP INHIBITORS Omeprazole ↓ nelfinavir Omeprazole decreases the plasma concentrations of nelfinavir.
Nelfinavir label, drug interactionsPROTON PUMP INHIBITORS Omeprazole ↓ nelfinavir Omeprazole decreases the plasma concentrations of nelfinavir. Concomitant use of proton pump inhibitors and VIRACEPT may lead to a loss of virologic response and development of resistance.
Source: FDA drug label (VIRACEPT), AGOURON, effective December 11, 2025 (SPL set e72c2bc6-9462-4a2e-8e1d-b97592376cbd), 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
| Lansoprazole | Nelfinavir | |
|---|---|---|
| Labeled for | Acid reflux and ulcers | HIV |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.106 per capsule 30 mg capsule | 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