Trimethoprim-sulfamethoxazole (TMP-SMZ) is given to transplant recipients as prophylaxis for Pneumocystis jiroveci pneumonia. It causes photosensitivity, so the patient is instructed to wear sunscreen and protective clothing. In addition to the immunosuppression that occurs following an organ transplant, TMP-SMZ can cause blood dyscrasias, so the patient must take extra care to avoid infectious individuals. TMP-SMZ does not increase the chances of transplant rejection. It does, however, cause hepatitis and liver toxicity, so signs of jaundice should be reported promptly. TMP-SMZ does not cause the patient to become sensitive to new substances, so an epinephrine autoinjector is not necessary.