What the FDA labels say about taking them together
Nelfinavir and rifampin
Nelfinavir's FDA label of December 11, 2025 names rifampin in its contraindications section; the rifampin label PlainMeds reads does not name nelfinavir. The nelfinavir label: “Plasma concentrations of nelfinavir can be reduced by concomitant use of rifampin. This may lead to loss of therapeutic effect and possible development of resistance to VIRACEPT or other coadministered antiretroviral …”
Check it at the source: the nelfinavir FDA label on DailyMed (effective December 11, 2025, AGOURON); the rifampin FDA label on DailyMed (effective February 11, 2026, Lupin Pharmaceuticals, Inc.).
What does the nelfinavir label say about rifampin?
Nelfinavir label, contraindicationsDrug Class: Antimycobacterial Agents; Drugs Within Class That Are Contraindicated With VIRACEPT: Rifampin; Clinical Comment: Plasma concentrations of nelfinavir can be reduced by concomitant use of rifampin. This may lead to loss of therapeutic effect and possible development of resistance to VIRACEPT or other coadministered antiretroviral agents.
Nelfinavir label, drug interactionsCoadministration of VIRACEPT and drugs that induce CYP3A or CYP2C19, such as rifampin, may decrease nelfinavir plasma concentrations and reduce its therapeutic effect.
Source: FDA drug label (VIRACEPT), AGOURON, effective December 11, 2025 (SPL set e72c2bc6-9462-4a2e-8e1d-b97592376cbd), via openFDA; the full label on DailyMed
What does the rifampin label say about nelfinavir?
Rifampin's label (effective February 11, 2026) does not name nelfinavir in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (rifampin), Lupin Pharmaceuticals, Inc., effective February 11, 2026 (SPL set b56004f0-f23d-47f6-80c7-39884fccbccc), 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
| Nelfinavir | Rifampin | |
|---|---|---|
| Labeled for | HIV | n/a |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | n/a | $0.679 per capsule 300 mg capsule |
| Shortage now | No current entry | In shortage |
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