LACK OF EFFECT OF CIMETIDINE ON LYMPHOCYTE SUBSETS IN PATIENTS INFECTED WITH HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1

Cimetidine, widely used for peptic ulcer disease, blocks type 2 histam ine receptors present on immune cells, including T cells, B cells, and monocytes, As an earlier published study showed evidence of increases in CD4 cell counts due to this drug, we conducted a randomized, place bo-controlled, 8-week trial of oral cimetidine (400 mg po t.i.d.) in a study involving 182 patients infected with human immunodeficiency vir us (HIV), Overall, cimetidine-treated patients had a decline in CD4(+) cell counts that was no different from the decline for placebo-treate d persons, neither during the first 8 weeks of the trial (mean drop, 7 .1% [standard error, 12.1-1.8] vs. 6.7% [standard error, 11.6-1.5]) no r during the subsequent 8 weeks of open-label administration of cimeti dine. No differences were evident between the treatment groups in term s of the percentage reactive to p24 antigen at baseline, and p24 antig en concentrations did not change from baseline to the end of week 8. I n summary, cimetidine is well tolerated by HIV-infected individuals bu t alters neither CD4(+) cell counts nor at least one quantitative meas ure of viral load, HIV p24 antigen levels.