Before taking co-trimoxazole,
tell your doctor and pharmacist if you are allergic to co-trimoxazole, any other medications, or any ingredients in co-trimoxazole tablets and suspension. Ask your pharmacist for a list of ingredients.
tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention the following: amantadine; angiotensin converting enzyme inhibitors such as benazepril (Lotensin), captopril (Capoten), enalapril (Vasotec), fosinopril (Monopril), lisinopril (Prinivil, Zestril), moexipril (Univasc), perindopril (Aceon), quinapril (Accupril), ramipril (Altace), and trandolapril (Mavik); anticoagulants ('blood thinners') such as warfarin (Coumadin, Jantoven); cyclosporine (Gengraf, Neoral, Sandimmune); oral diabetes medications such as glipizide (Glucotrol), glyburide (Diabeta, Glynase), metformin (Fortamet, Glucophage), pioglitazone (Actos), repaglinide (Prandin), rosiglitazone (Avandia); digoxin (Lanoxin); diuretics ('water pills'); indomethacin (Indocin); leucovorin (Fusilev); medications for seizures such as phenytoin (Dilantin, Phenytek); memantine (Namenda); methotrexate (Trexall); pyrimethamine (Daraprim). and tricyclic antidepressants such as amitriptyline (Elavil), amoxapine (Asendin), desipramine (Norpramin), doxepin (Adapin, Sinequan), imipramine (Tofranil), nortriptyline (Aventyl, Pamelor), protriptyline (Vivactil), and trimipramine (Surmontil). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
tell your doctor if you have or have ever had thrombocytopenia (less than normal number of platelets) caused by taking sulfonamides or trimethoprim; megaloblastic anemia (abnormal red blood cells) caused by folate deficiency (low blood levels of folic acid), phenylketonuria (PKU, an inherited condition in which a special diet must be followed to prevent mental retardation), or liver or kidney disease. Your doctor may tell you not to take co-trimoxazole. Co-trimoxazole should not be used in children less than 2 months of age.
tell your doctor if you have or have ever had severe allergies; asthma; low levels of folic acid in the body which may be caused by malnutrition (you do not eat or cannot digest the nutrients needed for good health); human immunodeficiency virus (HIV) infection; porphyria (an inherited blood disease that may cause skin or nervous system problems); thyroid disease; or glucose-6-phosphate dehydrogenase (G-6-PD) deficiency (an inherited blood disease).
tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking co-trimoxazole, call your doctor immediately. Co-trimoxazole can harm the fetus.
plan to avoid unnecessary or prolonged exposure to sunlight and to wear protective clothing, sunglasses, and sunscreen. Co-trimoxazole may make your skin sensitive to sunlight.