Subscription is FREE for qualified healthcare professionals in the US.

Insights Into Patients’ Views About Topical Opioids: Observations From a Small Clinical Study

Central pain patients report that topical opioids are quite effective in controlling troublesome symptoms. They are inexpensive, have low abuse potential, and are easy to use with only a few side effects.
Page 2 of 2

Why patients use topical agents and what therapeutic effect they receive is critical to understanding the desire of central pain patients to use topical opioids and carisoprodol. About 66% of patients report using it when their pain sites begin to ache or flare. Periodic allodynia and hyperalgesia occur in these patients, and a significant percentage use their topical agents when burning or itching begins or when it is painful to touch the site. Approximately 33% use their topical agent to assist in mobilization and in getting out of bed each morning. More than 40% say topical opioids help them sleep, as insomnia is a severe problem encountered by patients with central pain. The excess sympathetic discharge, allodynia, and hyperalgesia that affect the skin are contributory factors to the severe insomnia observed in these patients.

Side Effects
Of the 37 patients in this study, 2 reported a side effect. One stated the topical agent caused some skin irritation that prevented its use as frequently as the desired. The second patient reported hives, which disappeared after she changed brands of the cold cream used to make the topical. We have previously performed serum testing on patients who used topical opioids. Two patients who reported topical morphine use four or more times per day showed trace serum 
levels up to 15 ng/mL.

Patients with chronic pain must be clinically evaluated to determine if they have central pain, peripheral pain, or a combination of both conditions. Patients with central pain have impaired neurologic mechanisms that inhibit descending pain signals emanating from the brain. The excess descending signals result in episodes of allodynia, hyperalgesia, and excess sympathetic discharge with such symptoms as tachycardia, hyperreflexia, diaphoresis, and vasoconstriction (cold extremities). Insomnia is at least partially related to uncontrolled, central output of pain signals.

Topical opioids and carisoprodol help control some of the symptoms and problems inherent to central pain. They are inexpensive, have low abuse potential, are easy to use, and are quite effective in controlling several troublesome symptoms.

Last updated on: November 17, 2011