Immunodeficient individuals are at higher risk for infection with Pneumocystis carinii and are frequently put on a regular preventive drug regimen of trimethoprim sulfa and/or inhaled pentamidine to avoid pneumocystis pneumonia.
2
Methotrexate should be used with caution in patients taking drugs known to have antifolate potential including nitrous oxide and trimethoprim.
3
These include penicillin, ampicillin, and amoxicillin; sulfisoxazole or sulfamethoxazole; trimethoprim; nitrofurantoin; cephalosporins; or fluoroquinolones.
4
Trimethoprim and nitrofurantoin are preferred for treating recurrent UTIs in women.
5
Women and teens with two or more UTIs within a six-month period sometimes are given prophylactic treatment, usually nitrofurantoin or trimethoprim for three to six months.