What the FDA labels say about taking them together
Haloperidol and sodium phenylbutyrate
Sodium phenylbutyrate's FDA label of July 17, 2026 names haloperidol in its drug interactions section; the haloperidol labels PlainMeds reads (2) do not name sodium phenylbutyrate. The sodium phenylbutyrate label: “DRUG INTERACTIONS Valproic Acid, Haloperidol, or Corticosteroids: May increase plasma ammonia level; monitor ammonia levels closely.”
Check it at the source: the haloperidol FDA label on DailyMed (effective April 23, 2026, PD-Rx Pharmaceuticals, Inc.); the sodium phenylbutyrate FDA label on DailyMed (effective July 17, 2026, Medunik USA).
What does the haloperidol label say about sodium phenylbutyrate?
Haloperidol's label (effective April 23, 2026) and its 1 other brand-application label do not name sodium phenylbutyrate in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Haloperidol), PD-Rx Pharmaceuticals, Inc., effective April 23, 2026 (SPL set 533b0b4c-cbd6-4ec0-a333-8b04b5b43a1d), via openFDA; the full label on DailyMed
What does the sodium phenylbutyrate label say about haloperidol?
Sodium phenylbutyrate label, drug interactionsDRUG INTERACTIONS Valproic Acid, Haloperidol, or Corticosteroids: May increase plasma ammonia level; monitor ammonia levels closely.
Source: FDA drug label (Olpruva, NDA214860), Acer Therapeutics Inc., effective December 18, 2024 (SPL set 89abc31c-43e8-4809-9eb7-172cb31a86f1), via openFDA
Source: FDA drug label (PHEBURANE), Medunik USA, effective July 17, 2026 (SPL set d15f2cbf-4d22-40b5-8ef9-16b9d323a7f9), 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
| Haloperidol | Sodium phenylbutyrate | |
|---|---|---|
| Labeled for | Schizophrenia | n/a |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $15.60 per mL 100 mg/mL vial | n/a |
| Shortage now | A presentation being discontinued | 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