O-Morphon1 mg/ml

O-Morphon is a semi-synthetic opioid agonist indicated for the management of pain in adults, classified by formulation and strength of evidence as follows:

Established / FDA-approved uses

• Immediate-release tablets: Management of acute, moderate-to-severe pain where an opioid analgesic is appropriate and for which alternative treatments are inadequate.
• Extended-release tablets: Management of pain severe enough to require daily, around-the-clock, long-term opioid treatment, when alternative treatment options (non-opioid analgesics, opioid combination products) are ineffective, not tolerated, or inadequate to provide sufficient pain management. Not indicated for pain that is mild, intermittent, or expected to resolve quickly, and not indicated on an as-needed (PRN) basis.

Not established / not appropriate

• Not indicated for use in opioid-non-tolerant patients for extended-release formulations except as directed by a physician experienced in opioid titration.
• Not indicated for mild pain or for pain that can be managed with non-opioid analgesics.

Because O-Morphon is a Schedule/controlled opioid analgesic, it should be reserved for patients for whom alternative treatment options are inadequate.

Each tablet/injectable formulation contains Oxymorphone Hydrochloride as the active pharmaceutical ingredient, available as immediate-release tablets and extended-release tablets in various strengths, and as an injectable solution in some markets. Exact strength and excipients vary by manufacturer and formulation; refer to the specific product label/pack insert for the precise composition of the product dispensed.

O-Morphon is a semi-synthetic, potent opioid analgesic structurally related to morphine. It is available in immediate-release formulations for acute pain and extended-release formulations for continuous, around-the-clock management of chronic severe pain. As a full mu-opioid receptor agonist, it carries a high potential for abuse, addiction, and serious, life-threatening respiratory depression, and is subject to controlled-substance regulations.

O-Morphon extended-release tablets are designed to be swallowed whole; they must never be crushed, chewed, dissolved, or split, as this destroys the extended-release mechanism and can cause rapid release and absorption of a potentially fatal dose.

O-Morphon belongs to the therapeutic class of opioid analgesics (narcotic analgesics), specifically a semi-synthetic morphinan-type full mu-opioid receptor agonist used for moderate-to-severe pain.

Oxymorphone Hydrochloride is a semi-synthetic opioid agonist that acts primarily at the mu-opioid receptor in the central nervous system, producing analgesia, sedation, and euphoria, with minimal affinity for delta- or kappa-opioid receptors. Activation of mu-receptors in the brain and spinal cord inhibits ascending pain-transmission pathways and alters perception of and emotional response to pain.

Pharmacokinetics

• Absorption: Oral bioavailability is low (~10%) due to extensive first-pass metabolism; bioavailability is markedly increased in patients with hepatic impairment and when taken with alcohol (particularly relevant to extended-release tablets, which must not be taken with alcohol).
• Metabolism: Metabolized mainly by glucuronidation (via UGT2B7) to oxymorphone-3-glucuronide, with minimal involvement of the cytochrome P450 system; this results in a lower potential for drug interactions mediated by CYP2D6 or CYP3A4 compared with some other opioids, though clinically significant interactions with other CNS depressants and serotonergic drugs still occur.
• Elimination: Primarily renal, as metabolites; a small fraction is excreted unchanged.

• Immediate-release tablets of O-Morphon should be taken on an empty stomach (at least 1 hour before or 2 hours after eating), as food increases absorption.
• Extended-release tablets must be swallowed whole, one tablet at a time, with enough water; never crushed, chewed, split, or dissolved, as this can cause rapid release of a potentially fatal dose.
• Avoid alcohol entirely while taking O-Morphon, especially the extended-release form, due to risk of rapid dose release ("dose dumping").
• Do not share this medicine with anyone else, even someone with similar symptoms; keep it secured away from children, visitors, and anyone with a history of substance misuse.

Clinically significant interactions with O-Morphon include:

• CNS depressants (benzodiazepines, other sedatives/hypnotics, general anesthetics, tranquilizers, other opioids, alcohol): Concomitant use increases the risk of profound sedation, respiratory depression, coma, and death. Reserve for patients in whom alternative treatment options are inadequate, and use the lowest effective doses for the shortest duration.
• Alcohol: Can cause rapid release of the entire dose from extended-release tablets, resulting in potentially fatal plasma levels; alcohol must be avoided.
• Monoamine oxidase inhibitors (MAOIs): Concurrent use or use within 14 days of MAOIs is contraindicated, due to risk of severe, unpredictable interactions.
• Serotonergic drugs (SSRIs, SNRIs, triptans, certain other agents): Increased risk of serotonin syndrome.
• Mixed agonist/antagonist and partial agonist opioids (e.g. pentazocine, butorphanol, nalbuphine, buprenorphine): May reduce analgesic effect and/or precipitate withdrawal symptoms.
• Muscle relaxants: May enhance neuromuscular blocking action and increase respiratory depression.
• Anticholinergic drugs: May increase risk of urinary retention and severe constipation.

Common and serious adverse effects associated with O-Morphon include:

Very common / common

• Nausea, vomiting, constipation
• Dizziness, drowsiness, sedation, headache
• Pruritus (itching), sweating
• Dry mouth

Serious (seek prompt medical attention)

• Life-threatening respiratory depression (slow, shallow, or stopped breathing)
• Severe hypotension, syncope
• Adrenal insufficiency (with prolonged use)
• Serotonin syndrome (when combined with serotonergic drugs)
• Severe allergic reaction (rash, swelling of face/throat, difficulty breathing)
• QT-related or cardiac effects (rare)

Tolerance and physical dependence commonly develop with regular use; this is an expected physiological response and is distinct from addiction, but requires gradual tapering to discontinue.

Pregnancy: Use O-Morphon during pregnancy only if clearly needed and if the potential benefit justifies the potential risk to the fetus; consult a physician before use. Prolonged use during pregnancy can cause neonatal opioid withdrawal syndrome (NOWS) in the newborn, which can be life-threatening if not recognized and treated, and requires management by clinicians familiar with neonatal opioid withdrawal.

Lactation: O-Morphon passes into breast milk and may cause sedation and respiratory depression in a breastfed infant. Breastfeeding is generally not recommended during treatment; consult a physician to weigh the benefits of breastfeeding against the risk of infant opioid exposure, and monitor the infant closely for sedation and adequate feeding if used.

Boxed warnings

• Addiction, abuse, and misuse: O-Morphon exposes patients to the risks of opioid addiction, abuse, and misuse, which can lead to overdose and death. Assess each patient's risk before prescribing and monitor regularly.
• Life-threatening respiratory depression: Risk is greatest during initiation of therapy or following a dose increase; monitor closely, especially in the first 24-72 hours.
• Accidental exposure: Accidental ingestion of even one dose, especially by children, can result in a fatal overdose.
• Neonatal opioid withdrawal syndrome: Prolonged use during pregnancy can cause NOWS in the newborn.
• Interaction with alcohol: Alcohol can cause rapid release of the extended-release dose, leading to fatal plasma levels; avoid alcohol completely.
• Swallow whole: Extended-release tablets must be swallowed whole; crushing, chewing, or dissolving can cause rapid release and absorption of a potentially fatal dose.

Other warnings and precautions

• Concomitant use with benzodiazepines or other CNS depressants (including alcohol) may result in profound sedation, respiratory depression, coma, and death; reserve for use only when alternative options are inadequate, at the lowest effective doses and shortest duration.
• Use with caution in patients with head injury or increased intracranial pressure, as opioids may obscure the clinical course and increase intracranial pressure.
• Use with caution in hepatic or renal impairment; dose adjustment is needed, and bioavailability is increased in hepatic impairment.
• May cause severe hypotension, particularly in volume-depleted patients.
• Naloxone (an opioid antagonist) should be available for emergency management of overdose.
• Risk of serotonin syndrome with concomitant serotonergic drugs.
• May mask the diagnosis or clinical course of acute abdominal conditions.
• Not recommended for use in patients with impaired consciousness or coma.

Signs of O-Morphon overdose include severe respiratory depression, extreme drowsiness progressing to stupor or coma, pinpoint pupils, cold and clammy skin, low blood pressure, and slow heart rate; overdose can be fatal.

This is a medical emergency. Seek immediate emergency medical attention or contact a poison control center. If available, naloxone should be administered by a trained person while awaiting emergency services, and the patient must be monitored closely, as repeat doses of naloxone may be required due to the duration of action of O-Morphon. Supportive care, including airway management and ventilatory support, may be necessary in a medical facility. Do not attempt to manage a suspected overdose at home without professional guidance.

Store at room temperature (below 30°C), away from light and moisture. Keep out of reach of children and store securely, as this is a controlled substance with high potential for diversion, misuse, and accidental fatal exposure. Dispose of unused or expired medicine through an approved take-back program rather than household trash.

Pediatric use

Safety and efficacy of O-Morphon have not been established in pediatric patients; it is not recommended for use in children.

Elderly

Elderly patients may be more sensitive to the sedative and respiratory-depressant effects of O-Morphon; start with a lower dose and titrate slowly, with close monitoring.

Hepatic impairment

Bioavailability of O-Morphon is increased in hepatic impairment; use a reduced starting dose and titrate cautiously. Extended-release tablets may be contraindicated for initiation in moderate-to-severe hepatic impairment depending on product labeling.

Renal impairment

Start at the lowest recommended dose and titrate slowly, monitoring for signs of toxicity.

Pregnant and breastfeeding women

See Pregnancy and Lactation section for detailed guidance.

O-Morphon should be used for the shortest duration consistent with treatment goals, at the lowest effective dose. Immediate-release formulations are intended for acute, short-term pain management; extended-release formulations are intended only for patients who require continuous, around-the-clock, long-term opioid therapy that cannot be managed by other means. Treatment duration and continued need should be reassessed regularly by the prescribing physician, and the drug should not be stopped abruptly after prolonged use without a physician-guided tapering plan.

Opioid analgesic (narcotic analgesic); semi-synthetic mu-opioid receptor agonist; Schedule/controlled substance.

Oxymorphone Hydrochloride is a full agonist at the mu-opioid receptor in the central nervous system, producing analgesia by inhibiting ascending pain pathways and altering the perception of and emotional response to pain, with concurrent CNS effects including sedation and respiratory depression.

C

Safety and efficacy of O-Morphon in pediatric patients have not been established; it is not recommended for use in children and adolescents under 18 years of age.