Sulfamethoxazole / Trimethoprim Dosage

The information at Drugs.com is not a substitute for medical advice. ALWAYS consult your doctor or pharmacist.

Usual Adult Dose for Pneumocystis Pneumonia

15 to 20 mg/kg/day (trimethoprim component) orally or IV in 3 to 4 equally divided doses every 6 to 8 hours; according to 1 investigator, 10 to 15 mg/kg/day (trimethoprim component) IV was sufficient in 10 patients

Duration: 14 to 21 days; treatment should be followed by chronic suppressive therapy

If the patient is hypoxemic, IV therapy is recommended. Oral therapy may be substituted once the patient is able to tolerate oral medications and improves clinically. During oral therapy, desirable sulfamethoxazole levels are 100 to 150 mcg/mL. Levels exceeding 200 mcg/mL are associated with more side effects. Trimethoprim levels should be maintained between 5 to 8 mcg/mL.

Usual Adult Dose for Pneumocystis Pneumonia Prophylaxis

Trimethoprim-sulfamethoxazole 160 mg-800 mg (1 double-strength tablet) orally once a day or 3 times a week

The dose should be doubled to 2 tablets if the patient has latently infected toxoplasmosis.

Duration: Therapy should be continued for as long as the patient is at risk for infection. Most experts implement prophylaxis as long as the CD4 count is less than 200 or the CD4% is less than 15% in HIV-infected patients, for at least 1 year in transplant patients, and indefinitely for lung transplant patients and patients with recurrent rejection.

Usual Adult Dose for Urinary Tract Infection

Oral: Trimethoprim-sulfamethoxazole 160 mg-800 mg (1 double-strength tablet) orally every 12 hours for 10 to 14 days

IV:
Severe infection: 8 to 10 mg/kg/day (trimethoprim component) IV in 2 to 4 equally divided doses every 6, 8, or 12 hours for up to 14 days; maximum recommended dose is 960 mg (trimethoprim component) per day

Usual Adult Dose for Pyelonephritis

Uncomplicated: Trimethoprim-sulfamethoxazole 160 mg-800 mg (1 double-strength tablet) orally every 12 hours for 7 to 14 days

Usual Adult Dose for Bronchitis

Acute bacterial exacerbation of chronic bronchitis: Trimethoprim-sulfamethoxazole 160 mg-800 mg (1 double-strength tablet) orally every 12 hours for 14 days

Usual Adult Dose for Traveler's Diarrhea

Trimethoprim-sulfamethoxazole 160 mg-800 mg (1 double-strength tablet) orally every 12 hours for 5 days

Usual Adult Dose for Shigellosis

Oral: Trimethoprim-sulfamethoxazole 160 mg-800 mg (1 double-strength tablet) orally every 12 hours for 5 days

IV: 8 to 10 mg/kg/day (trimethoprim component) IV in 2 to 4 equally divided doses every 6, 8, or 12 hours for 5 days; maximum recommended dose is 960 mg (trimethoprim component) per day

The patient should be instructed to use extraordinary sanitary precautions since Shigella is transmitted by the fecal-oral route, primarily by hand-to-mouth contact.

Usual Adult Dose for Otitis Media

Trimethoprim-sulfamethoxazole 160 mg-800 mg (1 double-strength tablet) orally every 12 hours for 10 to 14 days

Usual Adult Dose for Cystitis Prophylaxis

Trimethoprim-sulfamethoxazole 80 mg-400 mg (1 single-strength tablet) orally once a day or 3 times a week at bedtime

Some clinicians recommend that their female patients take this low dose postcoitally or 3 times a week, whichever is less frequent. Therapy should be continued for as long as the patient is at risk for infection.

Usual Adult Dose for Diverticulitis

Mild, outpatient: Trimethoprim-sulfamethoxazole 160 mg-800 mg (1 double-strength tablet) orally every 12 hours in combination with metronidazole 500 mg orally every 6 hours

Duration: 7 to 10 days

Usual Adult Dose for Epiglottitis

2.5 mg/kg (trimethoprim component) IV every 6 hours
or
3.3 mg/kg (trimethoprim component) IV every 8 hours
or
5 mg/kg (trimethoprim component) IV every 12 hours

Oral therapy may be substituted once the patient improves and is able to tolerate oral medication.

Usual Adult Dose for Granuloma Inguinale

Trimethoprim-sulfamethoxazole 160 mg-800 mg (1 double-strength tablet) orally twice a day for at least 3 weeks

Usual Adult Dose for Infection Prophylaxis

Trimethoprim-sulfamethoxazole 160 mg-800 mg (1 double-strength tablet) orally twice a day

Duration: Therapy is usually continued as long as there is risk of infection. Patients with neutropenia are usually treated until they are afebrile for 24 hours and the absolute neutrophil count is greater than 500 cells/mm3. Routine prophylaxis is generally not recommended for granulocytic patients unless they are at risk for Pneumocystis pneumonitis.

Usual Adult Dose for Melioidosis

After an initial 10 days of parenteral therapy with ceftazidime, imipenem, or meropenem: 5 mg/kg (trimethoprim component) orally twice a day plus doxycycline 100 mg orally twice a day plus chloramphenicol 10 mg/kg orally (not available in the United States) four times a day

Duration: Trimethoprim-sulfamethoxazole and doxycycline for 20 weeks; chloramphenicol for the first 8 weeks

Usual Adult Dose for Meningitis

5 mg/kg (trimethoprim component) IV every 6, 8, or 12 hours for 21 days to 6 weeks

Use in combination with chloramphenicol is an alternative for patients with beta-lactam allergy.

Usual Adult Dose for Nocardiosis

Cutaneous infection: 5 to 10 mg/kg/day (trimethoprim component) IV or orally in 2 to 4 divided doses

Severe infection (pulmonary/cerebral): 15 mg/kg/day (trimethoprim component) in 2 to 4 divided doses for 3 to 4 weeks, then 10 mg/kg/day (trimethoprim component) in 2 to 4 divided doses; may be initiated IV and converted to oral therapy (frequently converted to approximate dosages of oral solid dosage forms: 2 double-strength tablets [320 mg-1600 mg] every 8 to 12 hours)

Measurement of serum levels is advisable. Maximum plasma concentrations (Cmax) of 100 to 150 mcg/mL are recommended. Severe disease is often treated with addition of other agents, such as ceftriaxone, imipenem, or amikacin.

Duration: Not well standardized; most experts recommend at least 6 months for local disease in immunocompetent patients and 6 to 12 months or more for immunocompromised patients or patients with CNS disease

Usual Adult Dose for Pneumonia

2.5 mg/kg (trimethoprim component) orally or IV every 6 hours
or
3.3 mg/kg (trimethoprim component) orally or IV every 8 hours
or
5 mg/kg (trimethoprim component) orally or IV every 12 hours

Duration: 21 days; pneumococcal pneumonia may be completely treated in 7 to 10 days

Usual Adult Dose for Prostatitis

Trimethoprim-sulfamethoxazole 160 mg-800 mg (1 double-strength tablet) orally every 12 hours

Duration: Acute, 10 to 14 days; chronic, 1 to 3 months

Usual Adult Dose for Sinusitis

Trimethoprim-sulfamethoxazole 160 mg-800 mg (1 double-strength tablet) orally every 12 hours

Duration: 10 to 14 days; in some cases of recurrent or refractory sinusitis, therapy may be required for up to 3 to 4 weeks

Usual Adult Dose for Toxoplasmosis

5 mg/kg (trimethoprim component) IV every 12 hours

Duration: 4 weeks to 6 months or more, depending on the nature and severity of the infection; patients with AIDS are usually given high dose therapy for 4 to 6 weeks then maintained on oral trimethoprim-sulfamethoxazole for life

Usual Adult Dose for Toxoplasmosis - Prophylaxis

Trimethoprim-sulfamethoxazole 160 mg-800 mg (1 double-strength tablet) or 80 mg-400 mg (1 single-strength tablet) orally once a day

Duration: Therapy should be continued for as long as the patient is at risk for infection.

Usual Adult Dose for Upper Respiratory Tract Infection

Trimethoprim-sulfamethoxazole 160 mg-800 mg (1 double-strength tablet) orally every 12 hours

Usual Pediatric Dose for Otitis Media

2 months or older: 4 mg/kg (trimethoprim component) orally every 12 hours for 10 days

Usual Pediatric Dose for Urinary Tract Infection

2 months or older:
Oral: 4 mg/kg (trimethoprim component) orally every 12 hours for 10 to 14 days

IV:
Severe infection: 8 to 10 mg/kg/day (trimethoprim component) IV in 2 to 4 equally divided doses every 6, 8, or 12 hours for up to 14 days; maximum recommended dose is 960 mg (trimethoprim component) per day

Usual Pediatric Dose for Shigellosis

2 months or older:
Oral: 4 mg/kg (trimethoprim component) orally every 12 hours for 5 days

IV: 8 to 10 mg/kg/day (trimethoprim component) IV in 2 to 4 equally divided doses every 6, 8, or 12 hours for 5 days; maximum recommended dose is 960 mg (trimethoprim component) per day

Usual Pediatric Dose for Pneumocystis Pneumonia

2 months or older: 15 to 20 mg/kg/day (trimethoprim component) orally or IV in 3 to 4 equally divided doses every 6 to 8 hours for 14 to 21 days

Usual Pediatric Dose for Pneumocystis Pneumonia Prophylaxis

2 months or older: 75 mg/m2 (trimethoprim component) orally twice a day, on 3 consecutive days per week

The total daily dose should not exceed 320 mg (trimethoprim component).

Renal Dose Adjustments

Adults:
CrCl 15 to 30 mL/min: One-half the recommended dose may be given at the usual dosing interval or the usual dose may be given every 18 to 24 hours

CrCl 14 mL/min or less: Because both trimethoprim (TMP) and sulfamethoxazole (SMX) are primarily eliminated by the kidney, use is generally not recommended unless the patient can be closely monitored to prevent further renal damage and hemodialysis facilities are readily available. If TMP-SMX cannot be avoided in this patient, some experts recommend a reduced dosage.

Liver Dose Adjustments

The manufacturer recommends caution when administering this drug to patients with liver dysfunction. Trimethoprim-sulfamethoxazole is contraindicated in patients with significant hepatic damage.

Precautions

Trimethoprim-sulfamethoxazole (TMP-SMX) is contraindicated in infants less than 2 months of age, in patients with a history of drug-induced immune thrombocytopenia with the use of trimethoprim and/or sulfonamides, in patients with megaloblastic anemia due to folate deficiency, in patients with significant hepatic damage, in patients with severe renal insufficiency if renal function status cannot be monitored, in pregnant patients, and in nursing mothers.

Severe cases of thrombocytopenia that were fatal or life-threatening have been reported. Thrombocytopenia usually resolved within a week following discontinuation of TMP-SMX.

Fatalities associated with the administration of sulfonamides, although rare, have occurred due to severe reactions including Stevens-Johnson syndrome, toxic epidermal necrolysis, fulminant hepatic necrosis, agranulocytosis, aplastic anemia, and other blood dyscrasias. Sulfonamides should be discontinued at the first appearance of skin rash or any sign of adverse reaction. The development of rash, fever, sore throat, arthralgia, pallor, purpura, or jaundice may be early signs of a serious reaction.

Injectable formulations may contain sodium metabisulfite as a preservative, which may cause allergic reactions, anaphylactic symptoms, and asthmatic episodes (life-threatening or less severe) in sensitive patients.

Caution is recommended in patients with impaired renal or hepatic function, with possible folate deficiency (e.g., the elderly, chronic alcoholics, patients taking anticonvulsants, patients with malabsorption syndrome, or malnourished patients), with severe allergies, or with bronchial asthma.

Long-term administration and/or use of high doses may cause bone marrow depression, which can be reversed with leucovorin.

Hemolysis may occur in patients with glucose-6-phosphate dehydrogenase deficiency. This reaction is often dose-related.

Intravenous infusions should be stopped and restarted at another site if irritation and inflammation due to extravasation occur.

Patients with AIDS generally have a greater incidence of side effects compared to non-AIDS patients, including rash, fever, leukopenia, hyperkalemia, and elevated liver transaminases. Adverse effects are generally more severe in patients receiving TMP-SMX for Pneumocystis pneumonia (PCP) and less severe during PCP prophylaxis. Therapy with TMP-SMX should be reevaluated if skin rash or any sign of adverse reaction develops.

Frequent monitoring of complete blood counts is recommended. TMP-SMX should be discontinued if a decrease of any formed blood element is observed.

Urinalysis and renal function tests are also recommended, especially in patients with renal impairment. Close monitoring of serum potassium concentrations is recommended in AIDS patients, especially those with renal impairment, underlying potassium disorders, or those receiving concomitant drugs that may cause hyperkalemia.

Clostridium difficile associated diarrhea (CDAD) has been reported with almost all antibiotics and may potentially be life-threatening. Therefore, it is important to consider this diagnosis in patients who present with diarrhea following TMP-SMX therapy. Mild cases generally improve with discontinuation of the drug, while severe cases may require supportive therapy and treatment with an antimicrobial agent effective against C difficile. Hypertoxin producing strains of C difficile cause increased morbidity and mortality; these infections can be resistant to antimicrobial treatment and may necessitate colectomy.

Cautious use of sulfonamides is recommended in patients with porphyria or thyroid dysfunction. Some manufacturers recommend avoiding sulfonamides in patients with or at risk of acute porphyria.

To reduce the risk of development of drug-resistant organisms, antibiotics should only be used to treat or prevent proven or suspected infections caused by bacteria. Culture and susceptibility information should be considered when selecting treatment or, if no data are available, local epidemiology and susceptibility patterns may be considered when selecting empiric therapy. Patients should be advised to avoid missing doses and to complete the entire course of therapy.

Dialysis

Peritoneal dialysis is not effective and hemodialysis is only moderately effective in eliminating trimethoprim (TMP) and sulfamethoxazole (SMX). Because both TMP and SMX are moderately removed by hemodialysis, it is recommended that this drug be given after dialysis sessions if doses are scheduled to be given on the days this patient is dialyzed.

Other Comments

Adequate fluid intake and urinary output should be maintained to prevent crystalluria.

Sulfonamides should not be used for the treatment of infections due to Group A beta-hemolytic streptococci because the organisms may not be eradicated.

Hide
(web2)