tokens: We conducted a population - based 45 - day follow - up study of 232 , 390 people who were prescribed trimethoprim - sulfamethoxazole ( TMP - SMZ ) , 266 , 951 prescribed trimethoprim alone , and 196 , 397 prescribed cephalexin , to estimate the risk of serious liver , blood , skin , and renal disorders resulting in referral or hospitalization associated with these drugs .