What the FDA labels say about taking them together
Bupropion and phenobarbital
Bupropion's FDA label of June 21, 2024 names phenobarbital in its drug interactions section; the phenobarbital labels PlainMeds reads (2) do not name bupropion. The bupropion label: “CYP2B6 inducers: Dose increase may be necessary if coadministered with CYP2B6 inducers based on clinical exposure, but should not exceed the maximum dose.”
Check it at the source: the bupropion FDA label on DailyMed (effective June 21, 2024); the phenobarbital FDA label on DailyMed (effective August 27, 2026).
What does the bupropion label say about phenobarbital?
Bupropion label, drug interactionsCYP2B6 inducers: Dose increase may be necessary if coadministered with CYP2B6 inducers (e.g., ritonavir, lopinavir, efavirenz, carbamazepine, phenobarbital, and phenytoin) based on clinical response, but should not exceed the maximum recommended dose.
Aplenzin label (Bausch Health US, LLC, March 4, 2026), drug interactionsCYP2B6 inducers: Dose increase may be necessary if coadministered with CYP2B6 inducers (e.g., ritonavir, lopinavir, efavirenz, carbamazepine, phenobarbital, phenytoin) based on clinical exposure, but should not exceed the maximum dose.
Source: FDA drug label (Aplenzin, NDA022108), Bausch Health US, LLC, effective March 4, 2026 (SPL set 6494d2d9-0ce4-4126-b1c7-49684395942b), via openFDA
Source: FDA drug label (Wellbutrin Xl, NDA021515), Bausch Health US LLC, effective February 10, 2026 (SPL set a435da9d-f6e8-4ddc-897d-8cd2bf777b21), via openFDA
Source: FDA drug label (Bupropion Hcl Er (Xl), NDA022497), Lifestar Pharma LLC, effective February 4, 2026 (SPL set df959e1b-3f6d-42cf-8521-fe03b5a4ceb8), via openFDA
Source: FDA drug label (BUPROPION HYDROCHLORIDE), Epic Pharma LLC, effective June 21, 2024 (SPL set 9fb44e96-6160-4a4a-90cb-91764c0dcd89), via openFDA; the full label on DailyMed
What does the phenobarbital label say about bupropion?
Phenobarbital's label (effective August 27, 2026) and its 1 other brand-application label do not name bupropion 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
| Bupropion | Phenobarbital | |
|---|---|---|
| Labeled for | Depression, Quitting smoking | Seizures and epilepsy |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $0.0785 per tablet 150 mg tablet | $0.213 per tablet 100 mg tablet |
| Shortage now | No current entry | 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