Analgesics for acute pain: Meeting the United States Food and Drug Administration's requirements for proof of efficacy.
OBJECTIVE
To examine the United States Food and Drug Administration's (FDA) standards for reviews of the scientific basis for efficacy claims for newly approved oral analgesics.


METHODS
Comparison of the trial methodologies and results provided by the FDA's medical reviewer in the Summary Bases of Approval (SBA) for the 9 oral acute analgesics approved in the last 10 years: ketorolac, diclofenac potassium, bromfenac, tramadol, hydrocodone/ibuprofen fixed combination, celecoxib, rofecoxib, tramadol/acetaminophen, and valdecoxib.


RESULTS
For all 9 new analgesics, studies were conducted in patients with postoperative dental pain and nondental surgical pain. The relief of gynecologic pain was examined for 5 of the new drugs. No studies in other pain models (such as infection, neuropathy, and nonsurgical trauma) supported claims of efficacy for any of the new drugs. The overall designs of the dental and nondental surgical studies, including timing of the single dose of trial drug, timing of evaluations, scales used for evaluations, and the use of both measured and derived outcome variables, were similar across the 8 development programs fully described in SBAs. Other characteristics of the trials, including choice of population for efficacy analyses, methods of carrying forward pain intensity and pain relief scores, and the length of time patients were encouraged to refrain from use of rescue medication differed across the development programs.


CONCLUSIONS
The requirements for approval of new analgesics in the United States encourage the pharmaceutical industry to perform efficacy studies using stylized designs in dental and nondental surgical pain. Studies of the efficacy of new analgesics in other common clinical settings are rarely or never included in development programs.
Ridgway
Derry
D
Lineberry Research Associates, Research Triangle Park, NC, USA. ridgways@mindspring.com
D000208:Acute Disease; D000284:Administration, Oral; D000700:Analgesics / Q000627:therapeutic use*; D017277:Drug Approval; D006801:Humans; D015201:Meta-Analysis as Topic; D010146:Pain / Q000188:drug therapy*; D010147:Pain Measurement / Q000379:methods; D016032:Randomized Controlled Trials as Topic / Q000379:methods; D014481:United States; D014486:United States Food and Drug Administration / Q000592:standards*
D000700:Analgesics