What the FDA labels say about taking them together
Nafcillin and selegiline
Selegiline's FDA label (Zelapar) of June 1, 2021 names nafcillin in its drug interactions section; the nafcillin labels PlainMeds reads (2) do not name selegiline.
Check it at the source: the nafcillin FDA label on DailyMed (effective March 9, 2026, ONESOURCE SPECIALTY PHARMA LIMITED); the selegiline FDA label on DailyMed (effective August 7, 2024, Rising Pharma Holdings, Inc.).
What does the nafcillin label say about selegiline?
Nafcillin's label (effective March 9, 2026) and its 1 other brand-application label do not name selegiline in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (NAFCILLIN SODIUM), ONESOURCE SPECIALTY PHARMA LIMITED, effective March 9, 2026 (SPL set 4b3b8e52-df96-4886-e063-6294a90ac63f), via openFDA; the full label on DailyMed
What does the selegiline label say about nafcillin?
Zelapar label (Bausch Health US, LLC, June 1, 2021), drug interactionsDrugs that induce CYP3A4 (e.g., phenytoin, carbamazepine, nafcillin, phenobarbital, and rifampin) should be used with caution.
Source: FDA drug label (Zelapar, NDA021479), Bausch Health US, LLC, effective June 1, 2021 (SPL set 380d7717-2a79-42f3-a712-efe5e7696ba0), via openFDA
Source: FDA drug label (Selegiline Hydrochloride), Rising Pharma Holdings, Inc., effective August 7, 2024 (SPL set 23c4481f-d150-40c6-addb-b3e454ca914f), 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
| Nafcillin | Selegiline | |
|---|---|---|
| Labeled for | n/a | Parkinson's disease, Depression |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | n/a | $0.756 per capsule 5 mg capsule |
| Shortage now | No current entry | 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