Morphine

# morphine ## Overview - **Classification**: Opioid analgesic, Schedule II controlled substance - **Mechanism**: Binds to mu-opioid receptors in the CNS, spinal cord, and peripheral tissues, altering perception of pain and emotional response to pain. ## Primary Indications 1. **Management of acute and chronic pain** - Moderate to severe pain, including post-surgical, cancer-related, and palliative care pain. 2. **Pre-anesthetic medication** - To sedate patients and reduce anxiety before surgery. 3. **Adjunct to anesthesia** - For analgesia during surgical procedures. ## Adult Dosing ### Standard Dosing **Acute Pain (e.g., Post-operative Pain)** - **Dose**: **IV/IM/SC**: **2-10 mg** - **Frequency**: Every **3-4 hours** as needed - **Route**: Intravenous (IV), Intramuscular (IM), Subcutaneous (SC) - **Special Considerations**: Administer IV slowly over 4-5 minutes to minimize adverse effects. Titrate to effect. **Chronic Pain (e.g., Cancer Pain) - Oral Immediate Release** - **Dose**: **PO**: **10-30 mg** - **Frequency**: Every **4 hours** as needed or scheduled - **Route**: Oral (PO) - **Special Considerations**: Often used for breakthrough pain in patients on extended-release opioids. **Chronic Pain - Oral Extended Release (ER)** - **Dose**: **PO**: Initial dose typically **15-30 mg** - **Frequency**: Every **8-12 hours** - **Route**: Oral (PO) - **Special Considerations**: Convert from other opioids carefully. Do not crush or chew ER formulations. ### Dose Adjustments - **Renal Impairment**: Active metabolite (morphine-6-glucuronide) accumulates. - **CrCl 10-50 mL/min**: Reduce dose by **25-50%**. - **CrCl <10 mL/min**: Reduce dose by **50-75%**; use with extreme caution. - **Hepatic Impairment**: Metabolism may be reduced. - Start with **lower doses** and titrate slowly. Monitor closely for sedation and respiratory depression. - **Elderly Patients**: More sensitive to opioid effects. - Start with **lower doses (e.g., 50% of usual adult dose)** and titrate slowly. Increased risk of respiratory depression and constipation. ## Pediatric Dosing ### Neonates (0-28 days) - **Indication**: Pain management (e.g., post-operative) - **Dose**: **IV**: **0.05-0.1 mg/kg/dose** - **Frequency**: Every **4-6 hours** - **Maximum**: **0.1 mg/kg/dose** - **Special Notes**: Use with extreme caution due to immature renal/hepatic function. Prolonged duration of action. Monitor respiratory rate and sedation closely. ### Infants (1-12 months) - **Indication**: Pain management - **Dose**: **IV/IM/SC**: **0.05-0.2 mg/kg/dose** - **Frequency**: Every **2-4 hours** as needed - **Maximum**: **0.2 mg/kg/dose** - **Special Notes**: Oral dosing is less common due to variable absorption; if used, typically 0.2-0.5 mg/kg/dose. ### Children (1-12 years) - **Indication**: Pain management - **Dose**: **IV/IM/SC**: **0.1-0.2 mg/kg/dose** - **Frequency**: Every **2-4 hours** as needed - **Maximum**: **15 mg/dose** (IV/IM/SC) or **20 mg/dose** (Oral immediate release) - **Special Notes**: **PO (immediate release)**: **0.2-0.5 mg/kg/dose** every 4-6 hours. ### Adolescents (13-18 years) - **Indication**: Pain management - **Dose**: Dosing generally approaches **adult recommendations**. - **Maximum**: Same as **adult maximum doses**. - **Special Notes**: Consider starting with lower end of adult range and titrate. ## Safety Information ### Contraindications - **Absolute**: Significant respiratory depression (in unmonitored settings). - **Absolute**: Acute or severe bronchial asthma (in unmonitored settings or absence of resuscitative equipment). - **Absolute**: Known or suspected paralytic ileus. - **Absolute**: Hypersensitivity to morphine or other opioids. - **Relative**: Acute alcohol intoxication, head injuries, GI obstruction. ### Common Adverse Effects - **Very Common (>10%)**: Nausea, vomiting, constipation, sedation, dizziness, sweating. - **Common (1-10%)**: Dry mouth, pruritus, urinary retention, headache, confusion. - **Serious but Rare**: Respiratory depression, circulatory depression, apnea, shock, seizures, severe hypotension. ### Key Drug Interactions - **CNS Depressants (e.g., benzodiazepines, alcohol, hypnotics)**: Increased risk of profound sedation, respiratory depression, coma, and death. AVOID concomitant use. - **Serotonergic Drugs (e.g., SSRIs, SNRIs, triptans, TCAs)**: Potential for serotonin syndrome (agitation, hyperreflexia, fever). Monitor closely. - **Mixed Opioid Agonist/Antagonists (e.g., buprenorphine, nalbuphine)**: May reduce morphine's analgesic effect and/or precipitate withdrawal symptoms. - **CYP2D6 Inhibitors (e.g., quinidine, fluoxetine)**: May decrease conversion to active metabolite, potentially reducing efficacy. ## Monitoring & Follow-up - **Before Treatment**: Assess pain level, respiratory status, history of substance use disorder, bowel function. - **During Treatment**: Monitor respiratory rate and depth, oxygen saturation, sedation level (e.g., Pasero Opioid-Induced Sedation Scale), pain level. - **Clinical Signs**: Watch for excessive sedation, pinpoint pupils, shallow breathing, decreased bowel sounds. Constipation is nearly universal. ## Clinical Pearls - 💡 **Titrate Slowly**: Especially IV, give over 4-5 minutes to reduce nausea/vomiting and respiratory depression. - 💡 **Prophylactic Bowel Regimen**: Initiate a stimulant laxative (e.g., senna) and stool softener (e.g., docusate) concurrently with chronic opioid therapy to prevent constipation. - 💡 **Naloxone Availability**: Consider prescribing or educating patients/caregivers on the use of naloxone for opioid overdose reversal. - 💡 **Patient Counseling**: Counsel patients on risks of respiratory depression, sedation, and not to combine with alcohol or other CNS depressants. Do not share opioids. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.