Oxymorphone 15mg

What is Oxymorphone 15mg in Canada?

Oxymorphone 15mg is a semi-synthetic μ opioid agonist that is 1.2 times as potent as morphine in Canada. Despite being initially available as a parenteral injection and in suppository form, immediate-release and long-acting oral formulations have been developed, providing an alternative option for treating moderate to severe pain. Trials in both malignant and nonmalignant pain have confirmed its potential as a Step 3 option. Oxymorphone 15mg is more lipid soluble than morphine and has an oral bioavailability of approximately 10%, which is the lowest among oral Step 3 opioids. In healthy volunteers, the half-life ranges from 7.2 to 9.4 hours, longer than that of morphine and hydromorphone.

Immediate-release oxymorphone tablets in Canada may be given at 6-hour intervals, while the extended-release formula is dosed twice daily, reaching steady-state conditions after 3–4 days. Oxymorphone undergoes hepatic first-pass effects and is excreted by the kidneys, accumulating in renal failure with a prolonged half-life in such cases. Moreover, in the setting of hepatic insufficiency, it is recommended to increase the dosing interval. A pilot study by Sloan et al. comparing extended-release oxymorphone and controlled-release oxycodone in patients with moderate to severe cancer pain found similar tolerability and safety profiles (e.g., nausea, drowsiness, somnolence) between the two drugs, with no significant differences in daily pain intensity scores.

Major opioids in pain management

Oxymorphone 15mg is a semi-synthetic opioid that has been available as an IV preparation (Numorphan) since 1959 and as a rectal suppository in Canada. It wasn’t until 2006 that an oral formulation (Opana Immediate-Release and Extended-Release) was released. In Canada, Oxymorphone 15mg is primarily a μ-opioid receptor agonist with greater affinity for the μ-opioid receptor than morphine and is 10 times as potent as morphine when given intravenously. Unlike oxycodone, oxymorphone has little to no affinity for the κ-opioid receptor.

Oxymorphone has less histamine release from mast cells than morphine and is more lipid soluble than morphine and oxycodone, leading to maximum plasma concentrations in 30 minutes. Despite being well absorbed in the GI tract, Oxymorphone 15mg has a bioavailability of only 10% due to extensive first-pass hepatic metabolism. Its greater lipid solubility facilitates its ability to cross the blood-brain barrier, resulting in a rapid onset of analgesia. The onset of analgesia for the immediate-release formulation occurs in 30 to 60 minutes, allowing for predictable dosing, while the extended-release formulation reaches steady-state in three days with every 12-hour dosing.

Opioid Abuse and Opioid Epidemic

Please remember the following information about opioid abuse and the abuse of oxymorphone, a potent μ-opioid agonist. Oxymorphone, structurally related to oxycodone, is abused in Canada. It is twice as potent as oxycodone for pain relief. In a study by Babalonis et al., the direct physiological effects, abuse liability, analgesic profile, and overall potency of oxymorphone were compared to identical doses of oxycodone using nondependent opioid abusers. The study showed that oxymorphone produced fewer effects on measures of respiratory depression and experimental pain compared to oxycodone at identical doses. However, at higher doses, its abuse liability was found to be similar to oxycodone.