What the FDA labels say about taking them together
Griseofulvin and pentobarbital
Pentobarbital's FDA label of March 8, 2024 names griseofulvin in its drug interactions section; the griseofulvin label PlainMeds reads does not name pentobarbital. The pentobarbital label: “Griseofulvin: Phenobarbital appears to interfere with the absorption of orally administered griseofulvin, thus decreasing its blood level.”
Check it at the source: the griseofulvin FDA label on DailyMed (effective December 10, 2025); the pentobarbital FDA label on DailyMed (effective March 8, 2024, Hikma Pharmaceuticals USA Inc.).
What does the griseofulvin label say about pentobarbital?
Griseofulvin's label (effective December 10, 2025) does not name pentobarbital in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Ultramicrosize Griseofulvin), Chartwell RX, LLC., effective December 10, 2025 (SPL set efb8a660-802c-4ca6-bbff-ad7b48b91aef), via openFDA; the full label on DailyMed
What does the pentobarbital label say about griseofulvin?
Pentobarbital label, drug interactionsGriseofulvin: Phenobarbital appears to interfere with the absorption of orally administered griseofulvin, thus decreasing its blood level.
Source: FDA drug label (Pentobarbital Sodium), Hikma Pharmaceuticals USA Inc., effective March 8, 2024 (SPL set d375b92a-baa1-4d63-9ad1-1467dcfde7d5), 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
| Griseofulvin | Pentobarbital | |
|---|---|---|
| Labeled for | Fungal infections | Insomnia |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $3.74 per tablet 250 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