What the FDA labels say about taking them together
Hydrocortisone and phenobarbital
Hydrocortisone's FDA label (Alkindi Sprinkle) of April 21, 2026 names phenobarbital in its drug interactions section; the phenobarbital labels PlainMeds reads (2) do not name hydrocortisone. The hydrocortisone label: “Hydrocortisone is metabolized by cytochrome P450 3A4 (CYP3A4). Concomitant administration of inducers of CYP3A4 may lead to decreases in serum concentrations of ALKINDI SPRINKLE and increase the risk of adverse …”
Check it at the source: the hydrocortisone FDA label on DailyMed (effective August 19, 2026); the phenobarbital FDA label on DailyMed (effective August 27, 2026).
What does the hydrocortisone label say about phenobarbital?
Alkindi Sprinkle label (Eton Pharmaceuticals, Inc., April 21, 2026), drug interactionsClinical Impact: Hydrocortisone is metabolized by cytochrome P450 3A4 (CYP3A4). Concomitant administration of inducers of CYP3A4 may lead to decreases in serum concentrations of ALKINDI SPRINKLE and increase the risk of adverse reactions, including adrenal crisis. Intervention: Concomitant use of CYP3A4 inducers may require an increase in the ALKINDI SPRINKLE dose. Anticonvulsants: phenytoin, carbamazepine and oxcarbazepine Antibiotics: rifampicin and rifabutin Barbiturates: phenobarbital and primidone Antiretrovirals: efavirenz and nevirapine Estrogen and Estrogen …
Source: FDA drug label (Alkindi Sprinkle, NDA213876), Eton Pharmaceuticals, Inc., effective April 21, 2026 (SPL set 26c13a5f-7119-4c6a-bf10-fda4e07d7682), via openFDA
Source: FDA drug label (hydrocortisone 1), Kroger Company, effective August 19, 2026 (SPL set f05edff2-2dc5-427c-b52c-518e0aaef4e0), via openFDA; the full label on DailyMed
What does the phenobarbital label say about hydrocortisone?
Phenobarbital's label (effective August 27, 2026) and its 1 other brand-application label do not name hydrocortisone in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Phenobarbital), Chartwell RX, LLC, effective August 27, 2026 (SPL set 74428144-fb24-40a5-a670-3b876e2d116c), 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
| Hydrocortisone | Phenobarbital | |
|---|---|---|
| Labeled for | Osteoarthritis, Asthma, Allergies, Herpes and shingles, Leukemia, lymphoma and myeloma, Crohn's disease and ulcerative colitis, Eczema (atopic dermatitis) | Seizures and epilepsy |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $0.0613 per gram 1% cream | $0.213 per tablet 100 mg tablet |
| Shortage now | A presentation being discontinued | A presentation being discontinued |
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