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Urinary tract infection (lower) - women - Management
What are the precautions for trimethoprim?
Trimethoprim should be prescribed with caution in the following conditions:
- Severe renal impairment
- As the drug is predominantly excreted by the kidney, dose adjustment may be required. For further information, see Dosage.
- Folate deficiency
- Because of its potential anti-folate effect, there is a risk of further exacerbating folate deficiency in people who are folate deficient or who are predisposed to folate deficiency (for example elderly people). Consequently, consider prescribing a folate supplement (if this has not already been prescribed) — particularly if trimethoprim is prescribed long term.
- The risk of folate deficiency is also increased when trimethoprim is combined with certain drugs. For further information, see Drug interactions.
- Pregnancy
- Long-term trimethoprim treatment
- Because of the risk of haematological adverse effects (see Adverse effects), the British National Formulary (BNF) advises these people should be warned to seek immediate medical attention if the person develops signs of blood disorders.
- Although the manufacturer of trimethoprim recommends regular blood monitoring, the BNF found no practical evidence to support this.
[Actavis, 2007; BNF 57, 2009]
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