What the FDA labels say about taking them together
Cimetidine and morphine
Morphine's FDA label of July 13, 2026 names cimetidine in its drug interactions section; the cimetidine label PlainMeds reads does not name morphine. The morphine label: “Morphine may enhance the neuromuscular blocking action of skeletal muscle relaxants and produce an increased degree of respiratory depression.”
Check it at the source: the cimetidine FDA label on DailyMed (effective July 15, 2026, Mylan Pharmaceuticals Inc.); the morphine FDA label on DailyMed (effective July 13, 2026, Bryant Ranch Prepack).
What does the cimetidine label say about morphine?
Cimetidine's label (effective July 15, 2026) does not name morphine in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Cimetidine), Mylan Pharmaceuticals Inc., effective July 15, 2026 (SPL set 06c0a509-026f-44e0-9975-a94a8de51d43), via openFDA; the full label on DailyMed
What does the morphine label say about cimetidine?
Morphine label, drug interactionsClinical Impact: Morphine may enhance the neuromuscular blocking action of skeletal muscle relaxants and produce an increased degree of respiratory depression. … Dosage and Administration (2.2), Warnings and Precautions (5.3, 5.5)] Examples: Cyclobenzaprine, metaxalone Cimetidine
Ms Contin label (Rhodes Pharmaceuticals LLC, August 14, 2026), drug interactionsClinical Impact: Morphine may enhance the neuromuscular blocking action of skeletal muscle relaxants and produce an increased degree of respiratory depression. … and Administration (2.2), Warnings and Precautions (5.2 , 5.3) ]. Examples cyclobenzaprine, metaxalone Cimetidine
Morphine Sulfate label (Hikma Pharmaceuticals USA Inc., February 3, 2026), drug interactionsClinical Impact: The concomitant use of morphine and cimetidine has been reported to precipitate apnea, confusion, and muscle twitching in an isolated report. Intervention: Evaluate patients for increased respiratory and CNS depression when Morphine Sulfate Oral Solution is used concomitantly with cimetidine.
Source: FDA drug label (Ms Contin, NDA019516), Rhodes Pharmaceuticals LLC, effective August 14, 2026 (SPL set c354b3bf-86c0-4bb8-8b1f-be2164942698), via openFDA
Source: FDA drug label (Morphine Sulfate, NDA204223), Fresenius Kabi, USA LLC, effective August 31, 2026 (SPL set 1f53de80-efc8-4930-b3e3-fba0d026af05), via openFDA
Source: FDA drug label (Morphine Sulfate, NDA022195), Hikma Pharmaceuticals USA Inc., effective February 3, 2026 (SPL set ca359246-4674-4b32-b8b2-673d32b7112f), via openFDA
Source: FDA drug label (Morphine sulfate), ANDA078761 (Sun Pharm Inds Ltd), as published by Bryant Ranch Prepack, effective July 13, 2026 (SPL set 595243fe-a4b1-479a-99d6-a084a4181891), 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
| Cimetidine | Morphine | |
|---|---|---|
| Labeled for | Acid reflux and ulcers | Pain |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $0.236 per tablet 300 mg tablet | $0.226 per tablet 15 mg tablet |
| 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