Cotrimoxazol (Bactrim, Septra)

Sulfamethoxazole and trimethoprim are both antibiotics that treat different types of bacterial infections. Sulfamethoxazole and trimethoprim fight bacteria in your body.

Therapeutic actions:
Sulfamethoxazole inhibits bacterial synthesis of dihydrofolic acid by competing with para -aminobenzoic acid (PABA). Trimethoprim blocks the production of tetrahydrofolic acid from dihydrofolic acid by binding to and reversibly inhibiting the required enzyme, dihydrofolate reductase. Thus, Septra blocks two consecutive steps in the biosynthesis of nucleic acids and proteins essential to many bacteria.
In vitro studies have shown that bacterial resistance develops more slowly with Septra than with either trimethoprim or sulfamethoxazole alone.

What is it used for?:
Sulfamethoxazole and trimethoprim is used to treat infections such as urinary tract infections, bronchitis, ear infections (otitis), traveler's diarrhea, and Pneumocystis carinii pneumonia.

Contraindications and cautions:
• allergy to any ingredient in Septra or to similar medicines;
• severe allergic reaction to any other sulfonamide (sulfa) medicine (eg, glipizide, hydrochlorothiazide);
• taking dofetilide;
• anemia caused by low levels of folate in the blood or urinary blockage;
• 38 week of pregnancy or later (full-term) or breast-feeding;
• Children younger than 2 months old.

Side effects:
Less serious: appetite loss; nausea; vomiting. Serious: severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); blistered, peeling, red, or swollen skin; bloody or black, tarry stools; chest pain; chills, fever, or sore throat; unusual bruising or bleeding; depression; hallucinations; irregular heartbeat; vaginal irritation or discharge; unusually pale skin; joint or muscle pain; painful or stiff neck; purple patches under the skin; seizures; severe diarrhea; severe or persistent cough; decreased urination; severe or persistent headache; severe or persistent nausea or vomiting; shortness of breath; stomach cramps/pain; unusual tiredness or weakness; yellowing of the skin or eyes.

Interactions:
• Septra 's effectiveness may be decreased by Leucovorin;
• the risk of Septra 's side effects may be increased by angiotensin-converting enzyme (ACE) inhibitors (eg, enalapril) or diuretics (eg, hydrochlorothiazide);
• Anticoagulants (eg, warfarin) may increase the risk of bleeding;
• Dofetilide may increase the risk of severe heart problems;
• Septra may increase the risk of side effects of digoxin, methotrexate, phenytoin, sulfones (eg, dapsone), or sulfonylureas (eg, glipizide);
• effectiveness of cyclosporine may be decreased and the risk of liver side effects may be increased.