WHO Model Prescribing Information: Drugs used in Bacterial Infections
(2001; 179 pages) View the PDF document
Table of Contents
View the documentPreface
View the documentIntroduction
Open this folder and view contentsUpper respiratory tract infections
Open this folder and view contentsLower respiratory tract infections
Open this folder and view contentsOther respiratory tract infections
Open this folder and view contentsPerioral and dental infections
Open this folder and view contentsGastrointestinal tract infections
Open this folder and view contentsUrinary tract infections
Open this folder and view contentsSkin and soft tissue infections
Open this folder and view contentsBone and joint infections
Open this folder and view contentsSexually transmitted diseases
Open this folder and view contentsCardiovascular infections
Open this folder and view contentsCentral nervous system infections
Open this folder and view contentsMiscellaneous infections
Open this folder and view contentsSepticaemia
Close this folderDrugs (for details of contraindications, etc., see individual drug entries)
View the documentAmoxicillin
View the documentAmoxicillin + clavulanic acid
View the documentAmpicillin
View the documentBenzylpenicillin
View the documentBenzathine benzylpenicillin
View the documentProcaine benzylpenicillin
View the documentCefalexin
View the documentCefazolin
View the documentCefotaxime
View the documentCeftazidime
View the documentCeftriaxone
View the documentCefuroxime
View the documentChloramphenicol
View the documentCiprofloxacin
View the documentClindamycin
View the documentCloxacillin1
View the documentDoxycycline
View the documentErythromycin
View the documentGentamicin
View the documentImipenem + cilastatin
View the documentMetronidazole
View the documentNalidixic acid
View the documentNitrofurantoin
View the documentNystatin
View the documentPhenoxymethylpenicillin
View the documentRifampicin
View the documentSpectinomycin
View the documentStreptomycin
View the documentSulfadiazine
View the documentSulfamethoxazole + trimethoprim
View the documentTetracycline
View the documentTinidazole
View the documentTrimethoprim
View the documentVancomycin


Tablet, 100mg, 200mg

General information

Trimethoprim is an inhibitor of folic acid metabolism that is active against many Gram-positive cocci and Gram-negative bacilli.

Trimethoprim is well absorbed from the gastrointestinal tract and widely distributed in the tissues. It has a plasma halflife of about 11 hours and is excreted in the urine. It crosses the placenta and is excreted in breast milk.

Clinical information


Treatment of urinary tract infections and prostatitis in adults.

Dosage and administration

Urinary tract infections in adults

Women: 300 mg orally every 24 hours for 3 days (for uncomplicated infections).

Men: 300mg orally every 24 hours for at least 14 days.

Prostatitis in adults

200mg orally every 12 hours for 4 - 6 weeks.


• Pregnancy during the first trimester.
• Renal impairment (creatinine clearance <15ml/minute).
• Porphyria.


Trimethoprim should be used with caution in patients with folate deficiency, since haematological changes can occur. Folinic acid should be administered to these patients.

Use in pregnancy

Safe use in pregnancy has not been established. Treatment should be deferred until after the first trimester of pregnancy.

Adverse effects

The most frequent adverse effects are skin rashes and urticaria.

Rarely, exfoliative dermatitis and toxic epidermal necrolysis have been observed. Gastrointestinal disturbances have also been reported. Haematological reactions may occur in patients with folate deficiency.

Drug interactions

Trimethoprim inhibits hepatic metabolism.


Treatment is supportive and symptomatic.


Tablets should be stored in tightly closed containers, protected from light.

to previous section
to next section
The WHO Essential Medicines and Health Products Information Portal was designed and is maintained by Human Info NGO. Last updated: October 29, 2018