O-Morphon

Oxymorphone is a full opioid agonist and is relatively selective for the mu-opioid receptor, although it can bind to other opioid receptors at higher doses. The principal therapeutic action of oxymorphone is analgesia. Like all full opioid agonists, there is no ceiling effect for analgesia with oxymorphone. Clinically, dosage is titrated to provide adequate analgesia and may be limited by adverse reactions, including respiratory and CNS depression.

The precise mechanism of the analgesic action is unknown. However, specific CNS opioid receptors for endogenous compounds with opioid-like activity have been identified throughout the brain and spinal cord and are thought to play a role in the analgesic effects of this drug.

Clinical drug interaction studies with Oxymorphone showed no induction of CYP450 3A4 or 2C9 enzyme activity indicating that no dose adjustment for CYP 3A4 or 2C9 mediated drug-drug interactions is required.

General Disorders: Respiratory depression, Fatigue, Asthenia.
Metabolism and Nutrition Disorders: Anorexia.
Cardiac Disorders: Tachycardia, Bradycardia, Palpitations.
Eye Disorders: Miosis, Diplopia, Blurred vision.
Gastrointestinal Disorders: Vomiting, Constipation.
Psychiatric Disorders: Dysphoria, Euphoric mood, Nervousness, Restlessness, Insomnia, Agitation, Hallucination, Depression.
Vascular Disorders: Hypotension & Flushing.

Pregnancy Category C. The safety of using Oxymorphone in pregnancy has not been established with regard to possible adverse effects on fetal development. The use of Oxymorphone in pregnancy, in nursing mothers, or in women of child-bearing potential requires that the possible benefits of the drug be weighed against the possible hazards to the mother and the child.

Do not stop abruptly; taper gradually to stop treatment. Use caution in patients with acute pancreatitis, Addison disease, benign prostatic hyperplasia, cardiac arrhythmias, central nervous system (CNS) depression, drug abuse or dependence, emotional lability, gallbladder disease, gastrointestinal (Gl) disorder, pseudomembranous colitis, Gl surgery, head injury, hypothyroidism or untreated myxedema, intracranial hypertension, brain tumor, toxic psychosis, urethral stricture, urinary tract surgery, seizures, acute alcoholism, delirium tremens, shock, cor pulmonale, chronic pulmonary disease, emphysema, kyphoscoliosis, severe obesity, renal or hepatic impairment, elderly or debilitated patients.

Avoid alcohol. Reduce dosage if drug is coadministered with other CNS depressants. Thrombocytopenia purpura resulting in kidney failure or death has been reported when extended-release tablets are dissolved and injected IV. May obscure diagnosis of abdominal conditions.

Risk of opioid addiction, abuse, and misuse, which can lead to overdose and death Assess each patient’s risk prior to prescribing and monitor all patients regularly for the development of these behaviors or conditions Life-threatening respiratory depression, life-threatening, or fatal respiratory depression may occur

Monitor for respiratory depression, especially during initiation or following a dose increase

Pediatric use: Safety and effectiveness of Oxymorphone Hydrochloride tablet and injection in pediatric patients below the age of 18 years have not been established.

Geriatric use: Oxymorphone Hydrochloride tablet and injection should be used with caution in elderly patients. These adverse events included dizziness, somnolence, confusion and nausea.

Opioid analgesics

Signs and Symptoms: Acute overdosage with Oxymorphone is characterized by respiratory depression, extreme somnolence progressing to stupor or coma, skeletal muscle flaccidity, cold and clammy skin, constricted pupils and sometimes bradycardia and hypotension.

Treatment: In the treatment of Oxymorphone overdosage, primary attention should be given to the re-establishment of a patient airway and institution of assisted or controlled ventilation. Supportive measures (including oxygen and vasopressors) should be employed in the management of circulatory shock and pulmonary edema accompanying overdose as indicated. The opioid antagonist naloxone hydrochloride is a specific antidote against respiratory depression that may result from overdosage or unusual sensitivity to opioids including Oxymorphone

Tablet: Store in a cool and dry place, protect from light.
Injection: Store at 25°C, protect from light.