Oxycodone Combined With Many Drugs Pose Risk of Side Effects: Report

A recent study has found that combining the painkiller oxycodone with other drugs can cause unexpectedly increased or decreased effects, potentially putting patients at increased risk of excessive sedation or decreased pain fighting effects.

The potential side effects of oxycodone were highlighted in an article published in this month’s edition of Worst Pills, Best Pills, a newsletter released by the consumer advocacy group Public Citizen. The publication lists 35 different medications that can interact with oxycodone, which is sold as a generic and under the brand names Oxycontin, Percodan and Tylox.

Oxycodone drug combination problems are the result of other drugs that interact with the liver enzyme CYP3A4, according to the Public Citizen report. This enzyme is necessary to metabolize oxycodone. Many drugs, like Nolvadex (tamoxifen) and Diflucan (fluconazole) inhibit CYP3A4, leading to an increased risk of oxycodone toxicity that can result in excessive drowsiness and slowed breathing. Other drugs, such as Dilantin (phenytoin) and St. John’s Wort are enzyme inducers, which increase the body’s production of CYP3A4, potentially resulting in a reduction of oxycodone’s painkilling benefits.

One study found that the CYP3A4 inhibitor voriconazole, sold under the brand name VFEND, resulted in a four-fold increase of oxycodone in the blood. VFEND is a prescription antibiotic.

Oxycodone was prescribed 14 million times last year. A complete list of drugs which may affect oxycodone can be found on their website WorstPills.org for a limited time.