O-Morphon

Indications

Oxymorphone Hydrochloride is a strong opioid painkiller used for severe pain that needs an opioid and for which other pain treatments are not enough. Immediate-release tablets and injections are used for acute severe pain, for example after surgery, and extended-release tablets for long-lasting severe pain needing round-the-clock treatment, as decided by a doctor.

How It Works

Oxymorphone attaches to opioid receptors (mainly mu receptors) in the brain and spinal cord. This changes the way the body feels and responds to pain, so pain is reduced. It is several times stronger than Morphine by weight.

Dosage and Administration

Use only exactly as prescribed. The dose is set individually by the doctor, starting low and adjusted carefully, especially in people who have not used opioids before. Tablets are usually taken on an empty stomach, at least 1 hour before or 2 hours after food. Swallow extended-release tablets whole; never crush, chew, break or dissolve them, as this can release a fatal dose. Injections are given by a doctor or nurse. Do not stop suddenly after regular use; the doctor will reduce the dose gradually.

Interactions

Taking it with Benzodiazepines (such as Diazepam), other opioids, sleeping pills, Gabapentin or Pregabalin, some antipsychotics, muscle relaxants or alcohol can cause dangerous slowing of breathing, coma and death. Avoid alcohol completely, especially with extended-release tablets. Do not use with, or within 14 days of, MAO inhibitors. Serotonin-affecting medicines can rarely cause serotonin syndrome. Mixed opioid agonist-antagonists (such as Pentazocine) can reduce its effect and cause withdrawal.

Contraindications

Do not use if you have severe breathing problems, acute or severe asthma, a blocked bowel (paralytic ileus), moderate to severe liver disease, or allergy to Oxymorphone. Not for mild pain or as-needed use with extended-release forms.

Side Effects

Common effects include constipation, nausea, vomiting, drowsiness, dizziness, itching, sweating, headache and confusion. Long-term use can lead to tolerance, physical dependence, addiction and hormone changes. Stopping suddenly causes withdrawal (restlessness, sweating, aches, diarrhoea).

Get urgent medical help if breathing becomes slow or shallow, if the person is very sleepy and hard to wake, has blue lips, fainting, a slow heartbeat, seizures, or signs of a severe allergic reaction. Family members should know these signs; Naloxone may be used as an emergency antidote.

Pregnancy and Lactation

Long-term use during pregnancy can cause neonatal opioid withdrawal syndrome in the newborn, which can be life-threatening. Use in pregnancy only if the doctor decides it is necessary. Breastfeeding is not recommended, as it can cause sleepiness and breathing problems in the baby.

Precautions and Warnings

Oxymorphone is a controlled medicine with a high risk of misuse and addiction. Keep it locked away; accidental swallowing, especially by children, can be fatal. Do not drive or operate machinery until you know how it affects you. Use with care in older people, kidney disease, head injury, low blood pressure, and lung disease.

Overdose

Overdose causes extreme sleepiness, pinpoint pupils, slow or stopped breathing, low blood pressure, coma and death. Call emergency services immediately. Naloxone can reverse the effects but may need repeating.

Therapeutic Class

Opioid analgesic (strong mu-opioid agonist).

Storage

Store below 30°C in a dry place, away from light, securely locked and out of the reach and sight of children. Dispose of unused medicine safely as advised by a pharmacist.