TRIMETHOPRIM

g. uncomplicated bacterial cystitis in women) and two weeks according to the nature and severity of infection. The first dose can be doubled.

Adults and children over 12 years:

For urinary tract and respiratory tract infections; 200mg twice daily.

Children 6 – 12 years: 100mg twice daily Children under 6 years of age:

Not recommended; a more suitable dosage form should be used in this age group.

Elderly:

Dosage is dependent upon kidney function; see special dosage schedule For long-term and prophylactic therapy of urinary tract infections Adults and children over 12 years: 100mg at night Children 6-12 years: 50mg at night. Where a single daily dose is required, dosage at bedtime may maximise urinary concentrations.

The approximate dosage in children is 2mg trimethoprim per kg body weight per day.

Elderly:

Dosage is dependent upon kidney; see special dosage schedule Advised dosage schedule where there is reduced kidney function eGFR (ml/min) Dosage advised Over 30 Normal 15-30 Normal for 3 days then half dose Under 15 Half the normal dose Monitoring of renal function and serum electrolytes should be considered particularly with longer term use, in patients with impaired renal function.

Trimethoprim should only be initiated and used in dialysis patients under close supervision from specialists in both infectious disease and renal medicine. Trimethoprim is removed by dialysis. Monitoring trimethoprim plasma concentration may be considered with long term therapy but the value of this in individual cases should first be discussed with specialists in infectious disease and renal medicine.

Route of administration:

For oral administration.

The most frequent adverse effects at usual doses are pruritus and skin rash (in about 3 to 7% of patients) and mild, gastrointestinal disturbances including nausea, vomiting and glossitis. These effects are generally mild and quickly reversible on withdrawal of the drug.

Infections and Infestations Common:

Monilial overgrowth Blood and lymphatic system disorders Very rare: Leucopenia, neutropenia, thrombocytopenia, pancytopaenia, bone marrow depression, agranulocytosis, aplastic anaemia, haemolytic anaemia, eosinophilia, purpura, haemolysis, Unknown: Megaloblastic anaemia, methaemoglobinaemia, hyperkalaemia (particularly in the elderly and in HIV patients), methaemoglobinaemia.

Trimethoprim therapy may affect haematopoiesis. 3 Contraindications), however the majority of haematological changes are mild and reversible when treatment is stopped.

Immune system disorders Very rare:

Hypersensitivity, anaphylaxis, anaphylactoid reaction, drug fever, allergic vasculitis resembling Henoch-Schoenlein purpura, periarteritis nodosa, systemic lupus erythematosus.

Metabolism and nutrition disorders Very common:

Hyperkalaemia Very rare: Hypoglycaemia, hyponatraemia, anorexia. Close supervision is recommended when Trimethoprim is used in elderly patients or in patients taking high doses as these patients may be more susceptible to hyperkalaemia and hyponatraemia Psychiatric disorders Very rare: Depression, hallucinations, confusional states, agitation, anxiety, abnormal behaviour, insomnia and nightmares.

Nervous system disorders Common:

Headache Very rare: Dyskinesias, aseptic meningitis, tremor, ataxia, dizziness, lethargy, syncope, paraesthesiae, convulsions, peripheral neuritis, vertigo, tinnitus. Aseptic meningitis was rapidly reversible on withdrawal of the drug, but recurred in a number of cases on re-exposure to either co-trimoxazole or to trimethoprim alone.

4 Special warning and precautions for use: Patients with marked impairment of renal function; care should be taken to avoid accumulation and resulting adverse haematological effects. Monitoring of renal function and serum electrolytes should be considered particularly with longer term use.

Trimethoprim should only be initiated and used in dialysis patients under close supervision from specialists in both infectious disease and renal medicine. Special precautions should be exercised in-patients with a predisposition to folate deficiency.

Administration of a folate supplement should be considered. Although an effect on folate metabolism is possible, interference with haematopoiesis rarely occurs at the recommended dose. If any such change is seen, folinic acid should reverse the effect.

Elderly people may be more susceptible and a lower dose may be advisable. Regular haematological tests should be undertaken in patients receiving long term treatment and those predisposed to folate deficiency. Particular care should be exercised in the haematological monitoring of children on long term therapy.

The usual caution in prescribing any drug for women of child bearing age should be exercised with trimethoprim. Trimethoprim should be used under careful medical supervision in neonates. Elevations in serum potassium have been observed in some patients treated with trimethoprim.

g. heparin). 5). Patients and their carers should be told how to recognise signs of blood disorders and advised to seek immediate medical attention if symptoms such as fever, sore throat, rash, mouth ulcers, purpura, bruising or bleeding develop Excipients This medicine contains lactose.

Patients with rare hereditary problems of galactose intolerance, total lactase deficiency or glucose-galactose malabsorption should not take this medicine. This medicine contains less than 1 mmol sodium (12mg) per tablet, that is to say essentially ‘sodium-free’.

3 Contra-indication: Hypersensitivity to trimethoprim or to any other component of the formulation. Should not be given to patients with severe hepatic insufficiency, megaloblastic Anaemia and other blood dyscrasias. Should not be administered to pregnant women, premature infants or during the first four months of life.

Patients with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galacactose malabsorption should not take this medicine.