What the FDA labels say about taking them together
Glycerol phenylbutyrate and midazolam
Glycerol phenylbutyrate's FDA label of October 29, 2025 names midazolam in its drug interactions section; the midazolam labels PlainMeds reads (4) do not name glycerol phenylbutyrate. The glycerol phenylbutyrate label: “Decreased exposure; monitor for suboptimal effect of midazolam.”
Check it at the source: the glycerol phenylbutyrate FDA label on DailyMed (effective October 29, 2025, Horizon Therapeutics USA, Inc.); the midazolam FDA label on DailyMed (effective January 1, 2024, Fresenius Kabi USA, LLC).
What does the glycerol phenylbutyrate label say about midazolam?
Glycerol phenylbutyrate label, drug interactionsDecreased exposure; monitor for suboptimal effect of midazolam.
Source: FDA drug label (Ravicti), Horizon Therapeutics USA, Inc., effective October 29, 2025 (SPL set 900e7dc0-9afe-4f50-80de-90567bb78519), via openFDA; the full label on DailyMed
What does the midazolam label say about glycerol phenylbutyrate?
Midazolam's label (effective January 1, 2024) and its 3 other brand-application labels do not name glycerol phenylbutyrate in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Midazolam), Fresenius Kabi USA, LLC, effective January 1, 2024 (SPL set 1cc9ba6e-fa1b-405e-9de8-720c567b2a73), 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
| Glycerol phenylbutyrate | Midazolam | |
|---|---|---|
| Labeled for | n/a | n/a |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | n/a | $0.233 per mL 2 mg/2 mL vial |
| Shortage now | A presentation being discontinued | 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