ASTRAMORPH PF
Clinical safety rating
cautionComprehensive clinical and safety monograph for ASTRAMORPH PF (ASTRAMORPH PF).
Mu-opioid receptor agonist; produces analgesia, sedation, and euphoria by mimicking endogenous endorphins.
| Metabolism | Primarily hepatic via glucuronidation (UGT2B7 and UGT1A3) and minor CYP3A4-mediated N-demethylation to normorphine. |
| Excretion | Renal: 70-80% unchanged; Biliary/Fecal: 10-20% as metabolites |
| Half-life | Terminal elimination half-life: 2-4 hours; prolonged in renal impairment (up to 12 hours in anuria) and elderly |
| Protein binding | 35% bound; primarily to albumin |
| Volume of Distribution | 3-5 L/kg; indicates extensive tissue distribution |
| Bioavailability | Oral: 50-60% (first-pass metabolism); Intramuscular: 80-90% |
| Onset of Action | Intravenous: 5-10 minutes; Intramuscular: 10-15 minutes; Oral: 30-60 minutes |
| Duration of Action | 4-6 hours for analgesia; prolonged in hepatic or renal impairment |
| Molecular Weight | 534.6 |
Intravenous: 8-10 mg over 2-5 minutes; may be repeated every 8-12 hours as needed. Oral (immediate release): 10-20 mg every 4-6 hours as needed. Oral (extended release): 10-40 mg every 12 hours.
| Dosage form | INJECTABLE |
| Renal impairment | For eGFR 30-50 mL/min: Reduce dose by 25-50% and extend dosing interval to every 12 hours. For eGFR <30 mL/min: Avoid use or reduce dose by 75% and extend interval to every 12-24 hours; monitor for neuroexcitation. |
| Liver impairment | Child-Pugh A: No adjustment. Child-Pugh B: Reduce dose by 50% every 8-12 hours. Child-Pugh C: Avoid use. |
| Pediatric use | Intravenous: 0.1-0.15 mg/kg/dose (max 10 mg) over 2-5 minutes every 8-12 hours as needed. Oral: 0.15-0.3 mg/kg/dose (max 15 mg) every 6-8 hours as needed. |
| Geriatric use | Initial dose should be reduced to 50% of adult dose (oral: 5-10 mg every 6-8 hours; IV: 4-5 mg over 2-5 minutes). Titrate slowly; maximum daily dose 60 mg. Avoid extended-release formulations. |
| 1st trimester | Avoid use during first trimester due to teratogenic effects observed in animal studies. |
| 2nd trimester | Use only if potential benefit justifies risk; may cause fetal harm. |
| 3rd trimester | Avoid use near term due to risk of neonatal hemorrhage. |
Clinical note
Comprehensive clinical and safety monograph for ASTRAMORPH PF (ASTRAMORPH PF).
| Placental transfer | Extensive placental transfer; crosses readily. |
| Breastfeeding | Not recommended during breastfeeding; unknown distribution into milk. |
| Lactation Rating | L5 (Contraindicated) |
| Teratogenic Risk | ASTRAMORPH PF (morphine sulfate) is Pregnancy Category C. First trimester: No well-controlled studies; potential for neural tube defects if used with other agents. Second/third trimesters: Chronic use may cause fetal opioid dependence and neonatal abstinence syndrome (NAS). Avoid during labor due to risk of neonatal respiratory depression. |
| Fetal Monitoring | Monitor maternal respiratory rate, sedation level, and bowel function. For fetus/neonate: Monitor for NAS (e.g., irritability, poor feeding) post-delivery. During labor, monitor fetal heart rate variability and respiratory status. |
| Fertility Effects | Chronic opioid use may disrupt hypothalamic-pituitary-gonadal axis, leading to oligomenorrhea, anovulation, or decreased libido in females. Males may experience erectile dysfunction and hypogonadism. Effects reversible upon discontinuation. |
■ FDA Black Box Warning
Risk of addiction, abuse, and misuse; life-threatening respiratory depression; accidental exposure; neonatal opioid withdrawal syndrome; risks from concomitant use with benzodiazepines or other CNS depressants.
| Serious Effects |
Hypersensitivity to active substanceSevere hepatic impairmentCurrent or recent varicella zoster infection
| Precautions | Respiratory depression, hypotension, seizures, serotonin syndrome, adrenal insufficiency, severe hypotension, biliary tract spasm, and risks in elderly, cachectic, or debilitated patients. |
| Food/Dietary | No known food interactions. However, alcohol and grapefruit juice may potentiate central nervous system depression and should be avoided. |
| Clinical Pearls | Astramorph PF (preservative-free morphine sulfate) is indicated for epidural or intrathecal administration. Monitor for delayed respiratory depression, particularly with intrathecal use, as it can occur up to 24 hours post-administration. Use with caution in patients with impaired pulmonary function, head injury, or increased intracranial pressure. Naloxone should be immediately available for reversal. Epidural doses typically range from 2-10 mg; intrathecal doses are 0.1-0.5 mg. Do not use if solution is discolored or contains particulate matter. |
| Patient Advice | Report any difficulty breathing, excessive drowsiness, or nausea immediately. · Avoid driving or operating heavy machinery until you know how this medication affects you. · Do not consume alcohol or other central nervous system depressants while using this medication. · This medication is given directly into the spinal fluid or epidural space; do not attempt to adjust the infusion pump yourself. · If you experience itching, rash, or swelling, contact your healthcare provider. |
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