DBL Sulfamethoxazole & Trimethoprim Dosage/Direction for Use

DBL Sulfamethoxazole 400 mg and Trimethoprim 80 mg Concentrate Injection BP must be diluted prior to administration. Sulfamethoxazole/trimethoprim should be administered intravenously only in the form of an infusion solution, and may not be injected undiluted either intravenously or direct into the infusion tube.
DBL Sulfamethoxazole 400 mg and Trimethoprim 80 mg Concentrate Injection BP may be mixed only with the following infusion solutions: 5% Glucose Injection; 4% Glucose/0.18% Sodium Chloride Injection; 0.9% Sodium Chloride; 10% Glucose Injection; 2.5% Glucose/0.45% Sodium Chloride Injection; 0.45% Sodium Chloride Injection; 10% Dextran 40 in 5% Glucose; 6% Dextran 70 in 0.9% Sodium Chloride Injection; Hartmann's Injection.
No other agent should be added to or mixed with the infusion.
It is important to adhere to the following minimum dilution scheme, which is based on a proportion of 1 mL DBL Sulfamethoxazole 400 mg and Trimethoprim 80 mg Concentrate Injection BP to 25 to 30 mL infusion fluid. Add one ampoule (5 mL) to 125 mL infusion solution; two ampoules (10 mL) to 250 mL infusion solution; or three ampoules (15 mL) to 500 mL infusion solution or an equivalent dilution.
The prepared infusion should be shaken well to ensure thorough mixing. Should visible turbidity or crystallisation appear in the solution during its preparation or infusion, it must be discarded and replaced by a freshly prepared solution.
It is recommended that infusion of sulfamethoxazole/trimethoprim be commenced within half an hour of preparation and the duration of infusion should not exceed 1.5 hours. However, this should be balanced against the fluid requirements of the patient.
To reduce microbiological hazards the prepared diluted solution should in any case be used as soon as practicable after preparation and within 24 hours. Do not refrigerate prepared solution.
Dosage for adults and children over 12 years: Standard dose: 10 mL diluted and infused twice daily.
For severe infections: 15 mL diluted and infused twice daily.
Dosage for children to 12 years: The recommended dosage is approximately 6 mg trimethoprim and 30 mg sulfamethoxazole per kg body weight per day, divided into two equal doses, morning and evening. As a guide, the following doses of DBL Sulfamethoxazole 400 mg and Trimethoprim 80 mg Concentrate Injection BP may be used: 2 months to 5 months: 1.25 mL diluted and infused twice daily.
6 months to 5 years: 2.5 mL diluted and infused twice daily.
6 years to 12 years: 5 mL diluted and infused twice daily.
The recommended dosage for patients with documented Pneumocystis carinii pneumonitis is 20 mg/kg trimethoprim and 100 mg/kg sulfamethoxazole per 24 hours given in equally divided doses every 6 hours for 14 days.
Dosage in reduced renal function: In patients with impaired renal function, the dosage and/or frequency of administration of sulfamethoxazole/trimethoprim needs to be modified.
The following dosage regimens have been published for the administration of sulfamethoxazole/trimethoprim tablets to patients with reduced kidney function. In view of the close similarity of plasma levels of trimethoprim and sulfamethoxazole when sulfamethoxazole/trimethoprim is given orally and intravenously, there is no reason to suppose that these regimens cannot be followed with DBL Sulfamethoxazole 400 mg and Trimethoprim 80 mg Concentrate Injection BP.
Criteria of kidney function: (See table.)

Click on icon to see table/diagram/image

Duration of treatment: DBL Sulfamethoxazole 400 mg and Trimethoprim 80 mg Concentrate Injection BP should be used ONLY during such periods as the patient is unable to accept oral therapy. In general, administration is unlikely to be required for more than a few days, and it is recommended that it be restricted to no more than three successive days.