A Topical Adhesive Containing Anesthetic and Heating Components to Reduce Injection Pain with Subcutaneous Multiple Sclerosis Medications: A Pilot Study

Injection pain and fear of pain are common with subcutaneous medications for treating multiple sclerosis (MS). Synera is a peel-and-stick topical adhesive (S-TA) with a novel heating component to enhance the delivery of an anesthetic mixture of lidocaine and tetracaine. We studied the effect of S-TA on pain and other aspects of comfort after subcutaneous MS drug injection. Thirty participants with MS having injection reactions to subcutaneous interferon beta (IFNβ) or glatiramer acetate (GA) were enrolled in an open-label prospective study. We captured six to seven injections at baseline and with 60- and 30-minute S-TA application times. The primary outcome was immediate pain on injection. Secondary outcomes included 12- and 24-hour pain ratings, 24-hour local injection-site reaction scale scores, 24-hour tenderness, and fear of injection (FOI). Twenty-nine participants completed the study (interferon beta = 4, GA = 25, mean age = 51 years, females = 86%). There were significant reductions in injection pain, pain at 12 and 24 hours, tenderness at 24 hours, local injection-site reaction scale scores, and FOI for the 30- and 60-minute applications of S-TA (all P < .01). Results were similar in the GA subgroup. Adverse events included muscle spasm and lightheadedness (n = 1) and mild dermatitis (n = 1). These results suggest that S-TA applied 30 or 60 minutes before MS drug injection may reduce pain, tenderness, and FOI. Randomized controlled studies are needed to confirm the efficacy of ST-A.