Diphenhydramine blocks the H1 receptor to treat pruritus or to induce sleep, while ranitidine blocks the H2 receptor to suppress gastric acid. They are often given to ill patients, such as those with perforated appendicitis. However, these receptors are integral to the inflammatory response, and to our knowledge, the impact of H1 or H2 blockade on outcome in the setting of perforated appendicitis has never been evaluated.
Prospective randomized trial.
Children undergoing an operation for perforated appendicitis from April 2005 to November 2006.
Main Outcome Measures
We conducted multivariate analysis with Pearson correlation on data from a prospective randomized trial comparing antibiotic regimen after appendectomy for perforated appendicitis and outcome. Medications with a significant correlation to abscess development were investigated by comparing those receiving the medication with those who did not using the t test for continuous variables and χ2 test for discrete variables. Significance was defined as P ≤ .05.
Significant correlations were found between the use of ranitidine (P = .05) or diphenhydramine (P = .03) and the development of an abscess. Direct comparison found no differences in patient or operative variables in those given either medication compared with those receiving no doses. Abscess rate in those receiving neither medication (n = 41) was 10%. Those given only ranitidine (n = 24) or diphenhydramine (n = 17) had doubled abscess rates of 17% and 18%, respectively. Those given both medications (n = 16) had a quadrupled abscess rate of 44% (P = .03).
Ranitidine or diphenhydramine given to patients with perforated appendicitis may increase the risk of postoperative abscess. Therefore, these medications should not be used empirically in this population.