What the FDA labels say about taking them together
Caffeine and phenelzine
Phenelzine's FDA label of June 6, 2025 names caffeine in its contraindications section; the caffeine labels PlainMeds reads (2) do not name phenelzine. The phenelzine label: “… Miscellaneous Yeast extract Meat extract Excessive amounts of chocolate and caffeine Also, any spoiled or improperly refrigerated, handled, or stored protein-rich foods such as meats, fish, and dairy products, including …”
Check it at the source: the caffeine FDA label on DailyMed (effective July 29, 2026, Sagent Pharmaceuticals); the phenelzine FDA label on DailyMed (effective June 6, 2025, Parke-Davis Div of Pfizer Inc).
What does the caffeine label say about phenelzine?
Caffeine's label (effective July 29, 2026) and its 1 other brand-application label do not name phenelzine in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (caffeine citrate), Sagent Pharmaceuticals, effective July 29, 2026 (SPL set 5f38c395-0093-4afd-89ec-f96e5dc0934a), via openFDA; the full label on DailyMed
What does the phenelzine label say about caffeine?
Phenelzine label, contraindicationsExcessive amounts of caffeine and chocolate may also cause hypertensive reactions.
Phenelzine label, warningsFoods and Beverages To Avoid Meat and Fish Pickled herring Liver Dry sausage (including Genoa salami, hard salami, pepperoni, and Lebanon bologna) Vegetables Broad bean pods (fava bean pods) Sauerkraut Dairy Products Cheese (cottage cheese and cream cheese are allowed) Yogurt Beverages Beer and wine Alcohol-free and reduced-alcohol beer and wine products Miscellaneous Yeast extract (including brewer's yeast in large quantities) Meat extract Excessive amounts of chocolate and caffeine Also, any spoiled or improperly refrigerated, handled, or stored protein-rich foods such as meats, fish, and dairy products, including foods that may have undergone protein changes by aging, pickling …
Source: FDA drug label (Nardil), Parke-Davis Div of Pfizer Inc, effective June 6, 2025 (SPL set 513a41d0-37d4-4355-8a6d-a2c643bce6fa), 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
| Caffeine | Phenelzine | |
|---|---|---|
| Labeled for | n/a | n/a |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $0.083 per tablet 200 mg tablet | $0.586 per tablet 15 mg tablet |
| 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