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NERVOUS SYSTEM › ANALGESICS › OPIOIDS › Natural opium alkaloids
morphine
N02AA01
Forms & Strengths
- Oral solution: 10 mg/5 mL, 20 mg/5 mL, 100 mg/5 mL (Concentrated)
- Immediate-release tablet: 15 mg, 30 mg
- Extended-release tablet/capsule: 10 mg, 15 mg, 30 mg, 60 mg, 100 mg, 200 mg
- Injection: 2 mg/mL, 4 mg/mL, 8 mg/mL, 10 mg/mL, 15 mg/mL
- Suppository: 5 mg, 10 mg, 20 mg, 30 mg
Adult Dosing
- Oral (Immediate-release): 10 to 30 mg every 4 hours as needed
- Oral (Extended-release): 15 to 30 mg every 8 to 12 hours
- IV/IM/SC: 2.5 to 10 mg every 2 to 6 hours as needed
- IV patient-controlled analgesia (PCA): 1 mg demand dose with 6-minute lockout
Pediatric Dosing
- Neonates (IV/IM/SC): 0.05 to 0.1 mg/kg every 4 to 8 hours
- Infants and Children (Oral): 0.2 to 0.5 mg/kg every 4 to 6 hours as needed
- Infants and Children (IV/IM/SC): 0.1 to 0.2 mg/kg every 2 to 4 hours as needed
- Continuous IV infusion (Children): 0.02 to 0.05 mg/kg/hour
Indications
- Management of moderate to severe acute pain
- Management of chronic severe pain requiring continuous around-the-clock opioid therapy
- Pain associated with myocardial infarction
- Dyspnea associated with acute left ventricular failure and pulmonary edema
Mechanism of Action
- Full mu-opioid receptor agonist in the central nervous system
- Binds to stereospecific receptors at multiple sites within the CNS
- Alters both perception of and emotional response to pain
- Inhibits ascending pain pathways and produces generalized CNS depression
Contraindications
- Significant respiratory depression
- Acute or severe bronchial asthma in an unmonitored setting or lack of resuscitative equipment
- Known or suspected gastrointestinal obstruction, including paralytic ileus
- Hypersensitivity to morphine
Adverse Reactions
- Respiratory depression
- Sedation, somnolence, dizziness
- Constipation, nausea, vomiting
- Hypotension, orthostatic hypotension
- Urinary retention
Drug Interactions
- CNS depressants (alcohol, benzodiazepines, other opioids): increased risk of profound sedation, respiratory depression, coma, and death
- Serotonergic drugs (SSRIs, SNRIs, MAO inhibitors): risk of serotonin syndrome
- Mixed agonist-antagonist/partial agonist opioids (buprenorphine, nalbuphine): may precipitate withdrawal or reduce analgesic effect
- CYP3A4 and P-glycoprotein inhibitors/inducers may alter clearance profile (though glucuronidation via UGT2B7 is primary metabolism pathway)
Curated Content: Needs Vetting Before Put to Clinical Use