TRIMETHOPRIM

Acute infections:

Treatment should continue for a period of between 3 days (eg, uncomplicated bacterial cystitis in women) to 2 weeks depending on the nature and severity of the infection. The first dose may be doubled.

Adults: 200mg twice daily Paediatric population:

Children over 12 years: Same as adult dose Children 6 - 12 years: 100mg twice daily Children under 6 years: This dosage form is not suitable for use in children younger than 6 years.

Elderly:

Dosage is dependent on renal function. See special dosage schedule below. 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.

Long-term treatment and prevention therapy:

Adults: 100mg at night Paediatric Population: Children over 12 years: Same as adult dose 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:

Dose depends on renal function. Refer to special dosage schedule above. Method of administration For oral administration.

The following list of undesirable effects have been reported by health care professionals. Sometimes it may be difficult to distinguish reactions caused by the condition being treated from adverse drug reactions, which means that not all the listed reactions were caused by drug 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, Not known: 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.

Eye disorders Very rare: uveitis Respiratory, thoracic and mediastinal disorders Very rare: Cough, shortness of breath, wheeze, epistaxis Gastrointestinal disorders Common: Nausea, diarrhoea, vomiting.

Very rare:

Constipation, glossitis, stomatitis, pseudomembranous colitis, pancreatitis.

Not known:

Sore mouth, Gastro-intestinal disturbance Hepatobiliary disorders Very rare: Disturbance in liver enzymes, elevation of serum transaminases, elevation of bilirubin levels, cholestatic jaundice, hepatic necrosis. Cholestatic jaundice and hepatic necrosis may be fatal.

Skin and subcutaneous tissue disorders Common:

Skin rashes, urticaria Very rare: Photosensitivity, exfoliative dermatitis, fixed drug eruption, erythema multiforme, erythema nodosum, Stevens-Johnson Syndrome, toxic epidermal necrolysis, bullous dermatitis, purpura, angioedema Not known: Pruritis, Drug reaction with eosinophilia and systemic symptoms (DRESS).

Lyell’s syndrome (toxic epidermal necrolysis) carries a high mortality.

Musculoskeletal and connective tissue disorders Very rare:

Arthralgia and myalgia Renal and urinary disorders Very rare: Impaired renal function (sometimes reported as renal failure), haematuria, Not known: Raised serum creatinine and blood urea nitrogen levels. It is not known however, whether this represents inhibition of creatinine tubular secretion or genuine renal dysfunction.

Reporting of suspected adverse reactions Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.

Patients with marked impairment of renal function:

Care should be taken to avoid accumulation and resulting adverse haematological effect. 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.

8). Patients should be advised of the signs and symptoms and monitored closely for skin reactions. If signs and symptoms suggestive of these reactions appear, trimethoprim should be withdrawn immediately and an alternative treatment considered (as appropriate).

If the patient has developed a serious reaction such as SJS, TEN or DRESS with the use of trimethoprim, the treatment must not be restarted in this patient at any time. g. the elderly), to check for possible pancytopaenia. 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. 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.

Particular care should be exercised in the haematological monitoring of children on long term therapy. Elevations in serum potassium have been observed in some patients treated with trimethoprim. g. heparin). 5). Caution should be used in patients with acute porphyria.

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 (23mg) per tablet, that is to say essentially ‘sodium-free’.

Severe hepatic insufficiency. Megaloblastic anaemia and other blood dyscrasias. Trimethoprim should not be administered to premature infants or children under 4 months of age. 6). 1).