Compounded pain creams ‘no better than placebo’ for pain relief

Compounded pain creams are no better than placebo creams for relieving localised pain, and come at a higher cost, according to results of a randomised control trial published in the Annals of Internal Medicine.

“We found no evidence of effectiveness in three compounded topical pain creams specially formulated to treat neuropathic, nociceptive, and mixed localized chronic pain,” write the authors. “Although participants in both treatment and control groups had improvement in their pain throughout the study, no significant differences were observed in pain scores, functional improvement, or satisfaction in the cohort or any subgroup.”

Chronic pain affects approximately 31 percent of the population, making it the leading cause of years lost to disability worldwide. Despite this burden, few reliable treatments exist for chronic pain.

To determine the efficacy of compounded creams for chronic pain, researchers from Walter Reed National Military Medical Center assigned 399 patients with localised pain to receive either a pain cream compounded for their type of pain or a placebo cream.

Localised pain was characterised as neuropathic (ie, from nerve damage, n=133), nociceptive (ie, from non-nerve tissue injury, n=133) or mixed (n=133).

The compounded pain creams included drugs that were FDA-approved or commonly used to treat the different pain conditions, such as muscle relaxants and non-steroidal anti-inflammatory drugs for nociceptive pain, and anticonvulsants for nerve pain.

The primary outcome measure was average pain score one month after treatment. A positive response was a reduction in pain score of two or more points coupled with a score above three on a five-point satisfaction scale. Secondary outcomes included Short Form-36 Health Survey scores, satisfaction, and categorical response. Participants with a positive outcome were followed through for three months.

After one month of treatment, the researchers found no significant differences between the real pain creams and placebo groups. They report no differences in the mean reduction in average pain scores between the treatment and control groups for patients with neuropathic pain (-0.1 points [95% CI,-0.8 to 0.5 points]), nociceptive pain (-0.3 points [CI, -0.9 to 0.2 points]), or mixed pain (-0.3 points [CI, -0.9 to 0.2 points]), or for all patients (-0.3 points [CI, -0.6 to 0.1 points]).

At one month, 72 participants (36 percent) in the treatment groups and 54 (28 percent) in the control group had a positive outcome (risk difference, 8 percent [CI, -1 percent to 17 percent]).

“Considering the increased costs of using a non-FDA-approved and regulated compounded cream rather than a single agent, we caution against routine use of compounded creams for chronic pain,” the authors conclude.

The full paper can be downloaded here.