Last reviewed 2026-04-22 · How we verify

Morphine-Promethazine

Morphine provides opioid analgesia while promethazine enhances pain relief and reduces nausea through antihistamine and anticholinergic effects.

Morphine provides opioid analgesia while promethazine enhances pain relief and reduces nausea through antihistamine and anticholinergic effects. Used for Moderate to severe pain, Post-operative pain management.

At a glance

Mechanism of action

Morphine acts as a mu-opioid receptor agonist to reduce pain perception and emotional response to pain. Promethazine is a first-generation antihistamine and anticholinergic agent that potentiates opioid analgesia, reduces nausea and vomiting, and provides sedation, making it a common adjunct in opioid formulations for enhanced therapeutic effect.

Approved indications

• Moderate to severe pain
• Post-operative pain management

Common side effects

• Drowsiness/sedation
• Constipation
• Nausea
• Dizziness
• Respiratory depression

Key clinical trials

• E7 TCR T Cells for Human Papillomavirus-Associated Cancers (PHASE1, PHASE2)
• A Study to Evaluate the Efficacy, Safety and Pharmacokinetics (PK) of a Higher Dose of Ocrelizumab in Adults With Relapsing Multiple Sclerosis (RMS) (PHASE3)
• Use of Driving Tests to Evaluate Patient Performance on Oral Opioids
• Recommendations of Enhanced Recovery Interventions for Patient's Clinical Team and Collection of Associated Data (PHASE3)
• Treatment of Pruritus With Intramuscular Promethazine (PHASE4)
• Study to Explore the Mechanism of Action of Ocrelizumab and B-Cell Biology in Participants With Relapsing Multiple Sclerosis (RMS) or Primary Progressive Multiple Sclerosis (PPMS) (PHASE3)
• A Controlled Study to Determine the Efficacy and Safety of CL-108 5 mg for Acute Pain and the Prevention of OINV (PHASE3)
• Preventative Delirium Protocol in Elderly Patients (NA)

Primary sources

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