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Correspondence

Sirs,

In UK general practice the choice of antibiotic is often made, and treatment commenced, before the laboratory report on the susceptibility of the causative organism is available. Knowing the probable infecting organism and its likely susceptibility is required. It is essential to base prescribing policy on local statistics in view of geographical variations which are known to occur.

A recent review of antibiotic policies and their relevance to general practice prescribing suggests that in the UK rational antimicrobial prescribing requires effective communication between the FHSA, microbiologists and GPs. Antimicrobial prescribing guidelines in the treatment of urinary tract infection were produced in Leicestershire and Derbyshire. The Leicestershire guidelines, based on local susceptibility data, drew attention to the substitution of trimethoprim alone for Co-trimoxazole.

In Epsom and Ewell in Surrey, 83% of urinary isolates from GPs (total 4082) in 1994 were coliforms. A breakdown of antibiotic sensitivities to coliforms showed 58% sensitivity to amoxycillin, 76% to trimethoprim, 90% to nitrofurantoin, 95% to cephalexin and 100% to ciprofloxacin (S Chambers, PHL Epsom, personal communication).

A cost analysis reveals that if the first-line treatment of patients with a coliform UTI (3394 isolates) was trimethoprim 200 mg twice a day for five days (cost of course £0.38), this would cost the locality £1,289. If the remaining 24% of patients who were resistant were then treated with cephalexin 500 mg three times daily for five days (cost of course £3.60) the combined cost would be £4,220. The cost of using cephalexin as first-line on all patients would be £12,218.

Both treatments would leave about 5% of patients resistant to treatment, though using trimethoprim first-line would result in saving £7,998 for the treatment of urinary tract infections in Epsom and Ewell. Given the development of locality purchasing, such cost analyses are becoming increasingly important.

In broad terms this suggests that to ensure an extra 20% of women receive an antibiotic to which they are sensitive would cost three times as much, against the price of a few extra days of discomfort.

We realise, of course, that sensitivities are in-vitro findings and may not always correlate with clinical response. However, the main message must be that rational prescribing of antimicrobials (that which is effective, appropriate, safe and economical) requires knowledge of local data, effective communication between GPs and microbiologists, and knowledge of the safety profiles of the drugs used.
Dr RM Martin GP, Dr S Pande GP Trainee, Mrs V Ainsworth In-house Pharmacist.
Fitznells Manor Surgery
Ewell, Surrey.

References

TM Hooton, C Winter, F Tiu, WE Stamm. Randomized comparative trial and cost analysis of 3-day antimicrobial regimens for treatment of acute cystitis in women. Journal of the American Medical Association 1995 273: 41-5.

British National Formulary, 1995

RC Spencer, PE Wheat, DM Harris. Microcomputer surveillance as an aid to rational antibiotic therapy for urinary tract infection in general practice. Health Trends 1986 18: 84-6.

RA Swann, J Clark. Antibiotic policies - relevance to general practitioner prescribing. Journal of Antimicrobial Chemotherapy 1994 33 (Supp 1): 131-5.



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