EMBEDA
Clinical safety rating: caution
Comprehensive clinical and safety monograph for EMBEDA (EMBEDA).
EMBEDA is a combination of morphine sulfate, a full opioid agonist, and naltrexone hydrochloride, an opioid antagonist. Morphine binds to mu-opioid receptors in the CNS, altering pain perception and response. Naltrexone is sequestered in the core and is released if the pellets are crushed or chewed, potentially precipitating withdrawal or blockade of morphine effects.
| Metabolism | Morphine is primarily metabolized via glucuronidation (UGT2B7) to morphine-3-glucuronide (M3G, major metabolite) and morphine-6-glucuronide (M6G, active). Naltrexone is metabolized by hepatic dihydrodiol dehydrogenase (DD) to 6-beta-naltrexol (active) and other minor metabolites. CYP450 enzymes are not significantly involved. |
| Excretion | Renal: ~60% (morphine), ~20% (naltrexone, in urine as unchanged drug and metabolites); biliary/fecal: ~10% (morphine-3-glucuronide and other metabolites). |
| Half-life | Morphine: 2-4 hours; naltrexone: 4-13 hours (active metabolite 6β-naltrexol: 12-18 hours). Clinically, morphine's half-life is prolonged in hepatic or renal impairment. |
| Protein binding | Morphine: ~30% bound, primarily to albumin; naltrexone: ~20% bound. |
| Volume of Distribution | Morphine: 1-4 L/kg; naltrexone: 2-4 L/kg. High Vd indicates extensive tissue distribution. |
| Bioavailability | Oral morphine: ~25-50% (first-pass metabolism); naltrexone: ~5-40% (first-pass metabolism forms active metabolite 6β-naltrexol). |
| Onset of Action | Oral: morphine absorption begins 30-60 minutes; peak analgesic effect 1-2 hours. |
| Duration of Action | Morphine: 4-6 hours (immediate-release formulation); extended-release properties of EMBEDA provide up to 12 hours of analgesia, but clinical duration varies with dose and patient response. |
1 to 2 capsules orally every 12 hours, titrated to pain relief. Maximum daily dose: 100 mg naltrexone (equivalent to 100 mg morphine). Capsules must be swallowed whole.
| Dosage form | CAPSULE, EXTENDED RELEASE |
| Renal impairment | GFR 30-89 mL/min: No adjustment needed. GFR 15-29 mL/min: Use with caution; consider dose reduction by 25-50%. GFR <15 mL/min: Contraindicated. |
| Liver impairment | Child-Pugh Class A: No adjustment. Child-Pugh Class B: Reduce dose by 50% or increase dosing interval. Child-Pugh Class C: Avoid use due to risk of naltrexone accumulation. |
| Pediatric use | Not approved for use in pediatric patients (age <18 years). |
| Geriatric use | Start at the low end of the dosing range (e.g., 20 mg/0.8 mg orally every 12 hours) and titrate cautiously. Monitor for respiratory depression and constipation. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for EMBEDA (EMBEDA).
| Breastfeeding | Excreted in human milk; M/P ratio not determined. Use caution; monitor infant for respiratory depression and sedation. Consider risk of infant opioid exposure. |
| Teratogenic Risk | Pregnancy Category C. First trimester: Limited data; potential risk of neural tube defects and minor malformations based on animal studies. Second and third trimesters: Prolonged use may cause neonatal opioid withdrawal syndrome (NOWS) and respiratory depression at birth. Avoid in pregnancy unless benefit outweighs risk. |
| Fetal Monitoring |
■ FDA Black Box Warning
WARNING: ADDICTION, ABUSE, AND MISUSE; LIFE-THREATENING RESPIRATORY DEPRESSION; ACCIDENTAL INGESTION; NEONATAL OPIOID WITHDRAWAL SYNDROME; CYTOCHROME P450 3A4 INTERACTION; RISKS FROM CONCOMITANT USE WITH BENZODIAZEPINES OR OTHER CNS DEPRESSANTS; RISK OF OPIOID WITHDRAWAL WITH CRUSHING, CHEWING, OR DISSOLVING
| Serious Effects |
["Hypersensitivity to morphine, naltrexone, or any component.","Significant respiratory depression (without resuscitation equipment).","Acute or severe bronchial asthma.","Known or suspected gastrointestinal obstruction, including paralytic ileus.","Concurrent use of monoamine oxidase inhibitors (MAOIs) or within 14 days of such therapy.","Opioid withdrawal syndrome – do not administer to patients with suspected or known opioid withdrawal."]
| Precautions | ["Addiction, abuse, and misuse – monitor for signs.","Life-threatening respiratory depression – risk increased in elderly, cachectic, or debilitated patients.","Accidental ingestion can be fatal.","Neonatal opioid withdrawal syndrome with prolonged use during pregnancy.","Opioid withdrawal if pellets are crushed, chewed, or dissolved – do not administer via nasogastric tube.","CYP3A4 interaction – avoid concomitant use with CYP3A4 inducers or inhibitors.","Risk of serotonin syndrome with serotonergic drugs.","Adrenal insufficiency and androgen deficiency with long-term use.","Severe hypotension, especially in hypovolemic patients.","Use with caution in patients with biliary tract disease, CNS depression, COPD, or sleep apnea."] |
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| Monitor maternal respiratory status, sedation level, and bowel function. Fetal monitoring: Assess fetal heart rate and growth. Neonatal monitoring: Observe for NOWS signs (irritability, hypertonia, tremors) for 48-72 hours after delivery. |
| Fertility Effects | May impair fertility in males and females due to opioid-induced hormonal changes (e.g., decreased libido, erectile dysfunction, menstrual irregularities). Reversible upon discontinuation. |