Purdue Pharma corporation, makers of the controversial painkiller OxyContin, reported this week that it expects to receive notification soon of patent approval for a "safer" form of the medication. The new pharmaceutical formulation would combine an opioid pain reliever with a "sequestered antagonist" that would work to help prevent the medication from being abused. Officials at Purdue Pharma say they are concerned about increased reports of abuse of OxyContin (controlled release oxycodone HCl) tablets. To address this growing problem, the company has been researching and developing pain relievers that are more resistant to abuse. Preliminary results appear to show some progress, according to Dr. Paul Goldenheim, Executive Vice President, Worldwide Research and Development.
One of our recent efforts focuses on the use of an antagonist to block the effect of the opioid if it is abused," says Goldenheim. "When appropriately taken by a pain patient, the tablet is swallowed whole, and the antagonist should pass through the gastrointestinal system of a patient without significant release. Preliminary in vitro studies to date have demonstrated that the release of the antagonist from the intact dosage form is minimal (<5% of total after 36 hours). When the dosage form is tampered, such as by crushing, in vitro results show that the entire amount of antagonist is released, thus potentially causing an undesirable effect to the abuser. If these results can be confirmed in clinical studies, this will be a significant technical achievement."
Drug abusers have learned to defeat the time-release properties of certain long-acting opioid analgesics, including OxyContin, by compromising the delivery system and then snorting or injecting them. However, says Goldenheim, "If this tablet is abused, preliminary in vitro studies show that it behaves in a completely different way. Crushing the tablet to defeat its time-release properties also releases the antagonist, which blocks the effects of the opioid. Abusers will not experience euphoria and may experience the uncomfortable effects of withdrawal. We hope that knowledge of the tablet's abuse-resistant properties will deter potential drug abusers from even trying this product."
While this abuse resistant pain reliever is still in the experimental phase of development, Purdue is planning to begin clinical trials early next year. Meanwhile, the labeling for OxyContin has been modified to contain the following warning for patients and physicians:
- OxyContin is an opioid agonist and a Schedule II controlled substance with an abuse liability similar to morphine.
- Oxycodone can be abused in a manner similar to other opioid agonists, legal or illicit. This should be considered when prescribing or dispensing OxyContin in situations where the physician or pharmacist is concerned about an increased risk of misuse, abuse, or diversion.
- OxyContin Tablets are a controlled-release oral formulation of oxycodone hydrochloride indicated for the management of moderate to severe pain when a continuous, around-the-clock analgesic is needed for an extended period of time.
- OxyContin Tablets are NOT intended for use as a prn [i.e. take as needed] analgesic.
- OxyContin 80 mg and 160 mg Tablets are for use in opioid-tolerant patients only. These tablet strengths may cause fatal respiratory depression when administered to patients not previously exposed to opioids.
- Oxycontin Tablets are to be swallowed whole and are not to be broken, chewed, or crushed. Taking broken, chewed, or crushed oxycontin tablets leads to rapid release and absorption of a potentially fatal dose of oxycodone.
Full prescribing information for OxyContin Tablets can be found online at the Purdue website, along with additional information about pain management. Revisit this About.com site for further information about OxyContin and the next generations of pain relief medications.
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