) is combination of trimethoprim and sulfamethoxazole
, two synthetic antibiotics. It is used in treating different bacterial infections. Some bacteria utilize folic acid for their growth and this ability of bacteria is reduced by sulfamethoxazole and trimethoprim both. Sulfamethoxazole is anti bacterial sulfonamide, the sulfa drug. Dihydrofolic acid production is disrupted by sulfamethoxazole and tetrahydrofolic acid production is disrupted by trimethoprim. Tetrahydrofolic acid and dihydrofolic acid are folic acid forms, which human cells and bacteria use for proteins production. Trimethoprim inhibits tetrahydrofolic acid production by inhibiting enzyme which is responsible for making the tetrahydrofolic acid from a dihydrofolic acid.
Combination of these two drugs interrupts two main steps which are required in bacterial proteins production and this combination is effective than either medicine alone. In 1973 Food and Drug Association approved Bactrim. Infections caused by susceptible bacteria are treated by Sulfamethoxazole/Trimethoprim (Bactrim). It is used for treating urinary tract infections, chromic bronchitis flares caused by bacteria, for preventing infections caused by pneumococcus, middle ear infections, chancroid, for preventing and treating Pneumocystis carinii pneumonia, and for preventing toxoplasma encephalitis in AIDS patients. Trimethoprim (Bactrim) is suggested to take with six to eight ounces of liquid for preventing crystal formation in the urine. People having advanced kidney disease can require lower doses. 1double strength tablet or 2 single strength tablets for ten to fourteen days every twelve hours is recommended as adult dose for treating urinary tract infections.
Displacement of Bilirubin from proteins in infant’s blood may be caused by use of Sulfamethoxazole/Trimethoprim (Bactrim). This may lead to a serious condition known as kernicterus and jaundice in the infant. Therefore use of this medicine is not suggested in pregnancy. Sulfamethoxazole/Trimethoprim (Bactrim) is passed in milk and may cause kernicterus. Nursing mothers should not use this medicine. Warfarin’s blood thinning effects may be enhanced by Bactrim and it may lead to bleeding. When urine is acidic sulfonamides may crystallize in urine. Acidic urine is caused by methenamine. So use of sulfonamides with methenamine is not suggested. Treatment of Sulfamethoxazole/Trimethoprim (Bactrim) can increase phenytoin blood levels. It can lead to reduced attention and dizziness which are side effects of phenytoin. Digoxin blood levels can increase with Bactrim which may lead to major toxic effects. Anemia caused by folic acid reduction may occur in people who are receiving combination of Sulfamethoxazole/Trimethoprim (Bactrim) with valproic acid, divalproex, methotrexate, triamterene, pyrimethamine or trimetrexate. Combination of Bactrim with ACE inhibitors may cause increased potassium blood levels.
Sulfamethoxazole/Trimethoprim (Bactrim) can cause headache, feeling short breath, cough, dizziness, lethargy, anorexia, diarrhea which is bloody or watery, nausea, rash and vomiting. Bactrim is suggested to stop at first appearance of the skin rash before it becomes severe. Major rashes involve Stevens Johnson syndrome, redness, peeling of skin, blistering, toxic epidermal necrolysis. This therapy may cause extensive sunburn when exposed to sunlight. Patients with this treatment should avoid extra exposure to sunlight. They may wear sunscreen. Liver damage, low platelet count, anemia and low white blood cell are some rare side effects of Sulfamethoxazole/Trimethoprim (Bactrim).