Oxycodone is an alternative to morphine for cancer pain

About half of people with advanced cancer suffer moderate to severe pain. Doctors generally prescribe medications called opioids to try to help relieve this pain, and the most frequently used opioid is morphine. Although morphine works well in most cases, approximately 20% of people end up switching to another drug. This is either because they don’t get adequate relief or because morphine’s side effects cannot be tolerated.

Oxycodone comes into its own

One alternative to morphine is oxycodone, a derivative of the opioid called codeine. In the U.S., this drug has most often been used in low doses together with aspirin or acetaminophen to counter mild to moderate pain. But since 1990, various studies have concluded that oxycodone—used by itself in
higher doses—often works as well as morphine. In 1996, the drug was relaunched in different strengths and formulations.

To find out if oxycodone is truly as effective as morphine, a team of British researchers reviewed 4 studies that compared the 2 drugs in their oral forms. All the people in the 4 studies suffered from cancer-related pain. The cancers varied in type, as did the intensity of the pain.

Based on the data that they reviewed (some of which went beyondthe published studies), the investigators found that oxycodone was similar to morphine in terms of both effectiveness and tolerability. There were no significant differences in pain relief and adverse effects between the 2 drugs.

Interpret with caution

However, the researchers noted that the total number of patients in the 4 studies was small (only 160). In addition, all the studies were of fairly short duration, and a considerable percentage of the
participants discontinued their medication due to adverse effects. For these reasons, the investigators say, the results of their review should be interpreted with caution. To provide more useful information, they urge larger studies of longer duration. In the meantime, oxycodone may be a useful alternative for cancer patients who cannot tolerate morphine.

From the Archives of Internal Medicine