Diphenhydramine (diphenhydramine) blocks H1 histamine receptors and is used to treat a number of allergic conditions with pruritus, or as a sedative. Ranitidine is an H2 blocker of histamine receptors and inhibits the secretion of hydrochloric acid. These drugs are often prescribed to patients, including patients with perforated appendicitis. However, histamine H1 and H2 receptors are an integral part of the inflammatory response, and the effect of drug blockage of histamine H1 and H2 receptors on the results of perforated appendicitis has never been studied in clinical trials.

In 2005-2006 A prospective randomized study was conducted at the Center for Prospective Clinical Research, Department of Surgery, and at the Children's Hospital of Mercy, University of Missouri (Kansas City, United States). The study involved children who underwent surgery for perforated appendicitis from April 2005 to November 2006. Data from a study comparing the antibiotic regimen prescribed after appendectomy for performative appendicitis and their effect on outcomes were analyzed using multivariate statistical analysis with Pearson correlation.

Drugs with a significant relationship between the development of abscesses were studied by comparing data from patients who received these drugs with patients for whom these drugs were not used, using the t-test for continuous variables and the criterion Χ²; for discrete quantities. The statistical significance of the differences was determined as a p-value less than 0.05.

Analysis revealed that there is a statistically significant relationship between the use of ranitidine (p = 0.05) and diphenhydramine (p = 0.03) and the development of a postoperative abscess. A direct comparison revealed no differences in baseline patient characteristics or surgical intervention characteristics between patients who received and did not receive ranitidine or diphenhydramine. The incidence rate of postoperative abscesses was 10% (n = 41) in the group of patients who did not receive any of these drugs, against an almost double increase in this indicator (17%, n = 24 and 18%, n = 17) in the patient groups receiving ranitidine and diphenhydramine, respectively. In addition, in the group of patients receiving the above two drugs (n = 16), the incidence of abscesses quadrupled.

Thus, the use of diphenhydramine and ranitidine in patients with perforated appendicitis may increase the risk of postoperative abscesses. These drugs should not be used routinely in this category of patients.