Opioid pain relievers, like morphine, carry warning labels urging patients not to drive or operate heavy machinery while taking the medication. Drivers under the influence of pain drugs are typically subject to the same laws and penalties as people who drink and drive.

A study by researchers at the Rush University Medical Center in Chicago recently performed a study that challenges the belief that moderate, long-term use of opioid pain medications impairs a person’s driving ability.

The study consisted of 2 groups of people. One group consisted of 51 long-term users of oral morphine. The control group consisted of 49 people who do not use an opioid pain medication. The participants all spent approximately 12 minutes in a driving stimulator that measures deviation from the center of the road, weaving, number of accidents, and the reaction time to unexpected events.

Both groups weaved an average of 3.83 feet from the center of the road. When it came to accidents, the non-pain medication group averaged 5.04 collisions, while the morphine user group averaged 5.33 collisions. Reaction times for both groups were also close with the morphine group doing slightly better at 0.67 seconds compared to the non-pain group with the average reaction time of 0.69 seconds.

The findings suggest that patients who require long-term pain medication may “become tolerant” to side effects that could potentially impair function and driving ability.