I get insomnia from bactrim (sulfamethoxazole and trimethoprim) ds 800-160. how long after taking a pill might this impact me?

See answer: The half-life of a drug is the time it takes for a drug to lose half (50%) of its pharmacologic or physiologic properties. The half-life of the two drug ingredients in Bactrim (sulfamethoxazole and trimethoprim) are 8 and 10 hrs. Therefore, after 5 half-lifes or 40 and 50 hrs for the 2 drugs, 97% of the drugs will be out of your system (~2 days). One would expect any related insomnia to be short?