What the FDA labels say about taking them together
Pentobarbital and valproic acid
Pentobarbital's FDA label of March 8, 2024 names valproic acid in its drug interactions section; the valproic acid label PlainMeds reads does not name pentobarbital. The pentobarbital label: “Sodium valproate and valproic acid appear to decrease barbiturate metabolism; therefore, barbiturate blood levels should be monitored and appropriate dosage adjustments made as indicated.”
Check it at the source: the pentobarbital FDA label on DailyMed (effective March 8, 2024, Hikma Pharmaceuticals USA Inc.); the valproic acid FDA label on DailyMed (effective January 24, 2025, PAI Holdings, LLC dba PAI Pharma).
What does the pentobarbital label say about valproic acid?
Pentobarbital label, drug interactionsSodium valproate and valproic acid appear to decrease barbiturate metabolism; therefore, barbiturate blood levels should be monitored and appropriate dosage adjustments made as indicated.
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
What does the valproic acid label say about pentobarbital?
Valproic acid's label (effective January 24, 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 (VALPROIC ACID), PAI Holdings, LLC dba PAI Pharma, effective January 24, 2025 (SPL set 7d5cb52e-37dd-4dfa-a6f4-09f9548846c6), 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
| Pentobarbital | Valproic acid | |
|---|---|---|
| Labeled for | Insomnia | Seizures and epilepsy, Migraine |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | n/a | $0.243 per capsule 250 mg capsule |
| Shortage now | No current entry | Listed; available |
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