What the FDA labels say about taking them together
Dextromethorphan and isocarboxazid
Isocarboxazid's FDA label of April 21, 2026 names dextromethorphan in its contraindications section; dextromethorphan's label does not name isocarboxazid itself but warns about its class (MAO inhibitors).
Check it at the source: the dextromethorphan FDA label on DailyMed (effective August 27, 2026); the isocarboxazid FDA label on DailyMed (effective April 21, 2026, Lifsa Drugs LLC).
What does the dextromethorphan label say about isocarboxazid?
Dextromethorphan's label does not name isocarboxazid itself; it warns about its class (MAO inhibitors):
Dextromethorphan label, warningsWarnings Do not use if you are now taking a prescription monoamine oxidase inhibitor (MAOI) (certain drugs for depression, psychiatric or emotional conditions, or Parkinson’s disease), or for 2 weeks after stopping the MAOI drug.
Dextromethorphan label, warningsIf you do not know if your prescription drug contains an MAOI, ask a doctor or pharmacist before taking this product.
Source: FDA drug label (Good Sense Cough DM), L. Perrigo Company, effective August 27, 2026 (SPL set 5a2e9bef-42cb-4b72-9a26-c3ae71dcb4ea), via openFDA; the full label on DailyMed
What does the isocarboxazid label say about dextromethorphan?
Isocarboxazid label, contraindicationsMAO inhibitors or dibenzazepine derivatives; sympathomimetics (including amphetamines); some central nervous system depressants (including narcotics and alcohol); antihypertensive, diuretic, antihistaminic, sedative or anesthetic drugs, buproprion HCL, buspirone HCL, dextromethorphan, cheese or other foods with a high tyramine content; or excessive quantities of caffeine.
Source: FDA drug label (MARPLAN), Lifsa Drugs LLC, effective April 21, 2026 (SPL set 95fde749-44ad-4668-86c4-0ff17bca0074), 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
| Dextromethorphan | Isocarboxazid | |
|---|---|---|
| Labeled for | Cough and cold | Depression |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $0.122 per unit 15 mg softgel | n/a |
| Shortage now | No current entry | 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