© 2014 by Lippincott Williams and Wilkins. Background: Results of previous studies suggest that β-adrenoreceptor activation may augment pain, and that β-adrenoreceptor antagonists may be effective in reducing pain, particularly in individuals not homozygous for the catechol-O-methyltransferase (COMT) high-activity haplotype.Materials and Methods: Consenting patients admitted for thermal burn injury at participating burn centers were genotyped; those who were not high-activity COMT homozygotes were randomized to propranolol 240 mg/d or placebo. Primary outcomes were study feasibility (consent rate, protocol completion rate) and pain scores on study days 5 to 19. Secondary outcomes assessed pain and posttraumatic stress disorder symptoms 6 weeks postinjury.Results: Seventy-seven percent (61/79) of eligible patients were consented and genotyped, and 77% (47/61) were genotype eligible and randomized. Ninety-one percent (43/47) tolerated study drug and completed primary outcome assessments. In intention-totreat and per-protocol analyses, patients randomized to propranolol had worse pain scores on study days 5 to 19.Conclusions: Genotype-specific pain medication interventions are feasible in hospitalized burn patients. Propranolol is unlikely to be a useful analgesic during the first few weeks after burn injury.