Use of Driving Tests to Evaluate Patient Performance on Oral Opioids (OpDrive)

• Weaving, measured as standard deviation of lateral position. [ Time Frame: 1 h ] [ Designated as safety issue: Yes ]
  

• Reaction time [ Time Frame: 1 h ] [ Designated as safety issue: Yes ]
  

Many patients seen at Pain Centers are advised not to drive if they are on long-term opioid medications. Although such advice is routinely given considering patients' safety, unnecessary restrictions to driving can cause inconvenience to the patients and delay their treatment. Such restrictions also pose social and legal questions to patients and physicians.

The investigators would like to test such patients' ability to drive under oral opioids using a driving simulator at the Pain Centre. This simulator is like a video game with computer and a steering wheel to simulate real life driving. The driving simulator provides measure on several outcome measures, such as attention, reaction time, etc. allowing us to specifically address question pertaining to any cognitive or behavioral differences.

A pilot phase, for feasibility, included 80 subjects. This phase will include a comparison with a random selection of 450 patients receiving one of the following 5 treatments:

Group 1 (IT): Subjects receiving 1-10 mg/day of morphine or its equivalent doses of opioid medications through intrathecal route. Intrathecal medications are administered through a catheter in spinal cord

Group 2 (Oral): Subjects receiving oral opioids (morphine, oxycodone, hydrocodone, methadone), but not also receiving anticonvulsants (gabapentin, pregabalin, topiramate), muscle relaxants, benzodiazepines, or diphenylhydramine for at least a week before testing; low dose antidepressants and/or NSAIDs are OK

Group 3 (Oral + Anticonvulsant): Subjects receiving oral opioids (morphine, oxycodone, hydrocodone, methadone) and anticonvulsants (gabapentin, pregabalin, topiramate), but not also receiving muscle relaxants, benzodiazepines, or diphenylhydramine for at least a week before testing; low dose antidepressants and/or NSAIDs are OK

Group 4 (Control -Pain) Subject not receiving opioid medications, anticonvulsants (gabapentin, pregabalin, topiramate), muscle relaxants, benzodiazepines, or diphenylhydramine for at least a week before testing; low dose antidepressants and/or NSAIDs are OK.

Group 5 (Control -No Pain) Age-matched volunteers (NO PAIN) not receiving opioid medications, anticonvulsants (gabapentin, pregabalin, topiramate), muscle relaxants, benzodiazepines, or diphenylhydramine for at least a week before testing; low dose antidepressants and/or NSAIDs are OK.

First group has 50 patients and the rest will have 100 patients each.