The effect of co-trimoxazole on thymidine uptake by transforming human lymphocytes in vitro
Rogers, H.J.; Lietman, P.S.
Journal of Pharmacy and Pharmacology 28(4): 328-329
1976
ISSN/ISBN: 0022-3573 PMID: 6732 Document Number: 97899
Gaylarde and Sarkany (1972) reported that co-trimoxazole (trimethoprim, TMP and sulfamethoxazole, SMX) decreases the uptake of labeled thymidine by human lymphocytes cultured in the presence of phytohemagglutinin in vitro. This phenomenon was pronounced (mean suppression 84%) but only observed in 60% of a small group of subjects. This could represent some pharmacogenetic difference between these 2 populations of subjects. During the course of a systematic study of the effects of TMP upon human lymphocytes stimulated to undergo lymphoblastic transformation with concanavalin A (con A) in vitro, these findings were investigated. Using drug concentrations similar to those employed by Gaylarde and Sarkany (SMX 2 .times. 10-5 M: TMP 5 .times. 10-6 M) no significant inhibitory effect could be detected. At a higher concentration of SMX (4 .times. 10-4 M which is .apprx. normal therapeutic plasma concn there was a small but statistically insignificant (t = 1.3) inhibitory effect while at 5 .times. 10-5 M, TMP (.apprx. normal plasma concn 10-5 M) clearly inhibits thymidine incorporation.