Sulfonamides and Trimethoprim (Systemic)

Proper Use of This Medicine

Sulfadiazine and trimethoprim combination should not be given to infants less than 3 months of age, and sulfamethoxazole and trimethoprim combination should not be given to infants less than 2 months of age unless directed by the child's doctor . These medicines may cause unwanted effects in the baby. In special situations, sulfamethoxazole and trimethoprim combination may be given to infants less than 2 months of age.

Sulfonamide and trimethoprim combinations are best taken with a full glass (8 ounces) of water. Several additional glasses of water should be taken every day , unless otherwise directed by your doctor. Drinking extra water will help to prevent some unwanted effects of sulfonamides.

For patients taking the oral liquid form of this medicine:

• Use a specially marked measuring spoon or other device to measure each dose accurately. The average household teaspoon may not hold the right amount of liquid.

To help clear up your infection completely, keep taking this medicine for the full time of treatment , even if you begin to feel better after a few days. If you stop taking this medicine too soon, your symptoms may return.

This medicine works best when there is a constant amount in the blood or urine. To help keep the amount constant, do not miss any doses. Also, it is best to take the doses at evenly spaced times day and night . If you need help in planning the best times to take your medicine, check with your health care professional.

Dosing - The dose of these medicines will be different for different patients. Follow your doctor's orders or the directions on the label . The following information includes only the average doses of these medicines. If your dose is different, do not change it unless your doctor tells you to do so.

The number of tablets or teaspoonfuls of suspension that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are taking sulfonamide and trimethoprim combinations .

For sulfadiazine and trimethoprim combination
• For oral dosage forms (suspension, tablets):
  • For bacterial infections:
    • Adults and teenagers - 820 milligrams (mg) of sulfadiazine and 180 mg of trimethoprim once a day.
    • Infants less than 3 months of age - Use is not recommended.
    • Infants 3 months of age and older and children up to 12 years of age - Dose is based on body weight. The usual dose is 7 mg of sulfadiazine and 1.5 mg of trimethoprim per kilogram (kg) (3.2 mg of sulfadiazine and 0.7 mg of trimethoprim per pound) of body weight every twelve hours.

For sulfamethoxazole and trimethoprim combination
• For oral dosage forms (suspension, tablets):
  • For bacterial infections:
    • Adults and children 40 kilograms (kg) of body weight (88 pounds) and over - 800 milligrams (mg) of sulfamethoxazole and 160 mg of trimethoprim every twelve hours.
    • Infants less than 2 months of age - Use is not recommended.
    • Infants 2 months of age and older and children up to 40 kg of weight (88 pounds) - Dose is based on body weight. The usual dose is 20 to 30 mg of sulfamethoxazole and 4 to 6 mg of trimethoprim per kg (9.1 to 13.6 mg of sulfamethoxazole and 1.8 to 2.7 mg of trimethoprim per pound) of body weight every twelve hours.
  • For the treatment of Pneumocystis carinii pneumonia (PCP):
    • Adults and children older than 2 months - Dose is based on body weight. The usual dose is 18.75 to 25 mg of sulfamethoxazole and 3.75 to 5 mg of trimethoprim per kg (8.5 to 11.4 mg of sulfamethoxazole and 1.7 to 2.3 mg of trimethoprim per pound) of body weight every six hours.
  • For the prevention of Pneumocystis carinii pneumonia (PCP):
    • Adults and teenagers - 800 mg of sulfamethoxazole and 160 mg of trimethoprim once a day.
    • Infants and children 4 weeks of age and older - Dose is based on body size and must be determined by your doctor. There are several dosing regimens available that your doctor may choose from. One dosing regimen is 375 mg of sulfamethoxazole and 75 mg of trimethoprim per square meter of body surface two times a day, three times a week on consecutive days (e.g., Monday, Tuesday, Wednesday).
• For injection dosage form:
  • For bacterial infections:
    • Adults and children older than 2 months - The usual total daily dose is 40 to 50 mg of sulfamethoxazole and 8 to 10 mg of trimethoprim per kg (18.2 to 22.7 mg of sulfamethoxazole and 3.6 to 4.5 mg of trimethoprim per pound) of body weight. This total daily dose may be divided up and injected into a vein every six, eight, or twelve hours.
    • Infants less than 2 months of age - Use is not recommended.
  • For the treatment of Pneumocystis carinii pneumonia (PCP):
    • Adults and children older than 2 months - The usual dose is 18.75 to 25 mg of sulfamethoxazole and 3.75 to 5 mg of trimethoprim per kg (8.5 to 11.4 mg of sulfamethoxazole and 1.7 to 2.3 mg of trimethoprim per pound) of body weight. This is injected into a vein every six hours.
    • Infants less than 2 months of age - Use is not recommended.

Missed dose - If you miss a dose of this medicine, take it as soon as possible. This will help to keep a constant amount of medicine in the blood or urine. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage - To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store the tablet form of this medicine in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Keep the oral liquid form of this medicine from freezing.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.