A Bactrim overdose can cause nausea, vomiting, and dizziness. As this eMedTV segment explains, an overdose can also lead to any of the usual side effects of the drug. Treatment options for an overdose are also listed in this article. Bactrim (sulfamethoxazole and trimethoprim) is a synthetic antibacterial combination product available in DS (double strength) tablets, each containing 800 mg sulfamethoxazole and 160 mg trimethoprim; in tablets, each containing 400 mg sulfamethoxazole and 80 mg trimethoprim for oral administration. Nausea, vomiting, loss of appetite, and allergic skin reactions are the most common side effects reported with Bactrim. Some of the problems that are less common (but are potentially serious) include watery or bloody diarrhea, shortness of breath, and decreased urination. Bactrim belongs to the class of drugs called sulfa drugs. Bactrim contains sulfamethoxazole, a form of sulfa and trimethoprim, a man-made antibiotic that enhances the effect of sulfamethoxazole. Sulfites in foods, despite the name similarity, have no connection to sulfa drugs. PRECAUTIONS: Before taking sulfamethoxazole with trimethoprim, tell your doctor or pharmacist if you are allergic to sulfa medications or trimethoprim; or if you have any other allergies. Allergies to sulfa drugs are a contraindication for taking Bactrim. In addition, pregnant or nursing people should not take Bactrim. There is an increasing concern in the health care community regarding the development of drug-resistant bacteria when undergoing long-term antibiotic therapy. Levaquin (levofloxacin) and Bactrim (sulfamethoxazole and trimethoprim) are antibiotics used to treat several types of bacterial infections. Levaquin and Bactrim belong to different drug classes. Levaquin is a fluoroquinolone antibiotic and Bactrim is a combination of a sulfonamide antibiotic (a The only notable nonsusceptible organisms are Pseudomonas aeruginosa, the mycoplasmae and Francisella tularensis (the causative organism of tularaemia). Bactrim (sulfamethoxazole and trimethoprim) is an antibiotic used to treat ear infections, urinary tract and other infections. Includes Bactrim side effects, interactions and indications. Bactrim (sulfamethoxazole and trimethoprim) DS is a combination of two antibiotics used to treat urinary tract infections, acute otitis media, bronchitis, Shigellosis, Pneumocystis pneumonia, traveler's diarrhea, methicillin-resistant Staphylococcus aureus , and other bacterial infections susceptible to this antibiotic.