An analysis of antibiotic prescriptions from general dental practitioners in England

Nikolaus O. A. Palmer*, Michael V. Martin, Rosemary Pealing and Robert S. Ireland

Department of Clinical Dental Sciences, University of Liverpool, Liverpool L69 3BX, UK


    Abstract
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
The aim of this study was to determine the antibiotics prescribed by general dental practitioners (GDPs). Adult antibiotic prescriptions issued by GDPs from 10 Health Authorities (HAs) in England were analysed. The type of antibiotic prescribed, dose, frequency and duration were investigated. Most of the 17007 prescriptions were for generic antibiotics; nine different antibiotics were prescribed. Many practitioners prescribed antibiotics inappropriately with inconsistent frequency and dose, and for prolonged periods.


    Introduction
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
General dental practitioners (GDPs) prescribe antibiotics therapeutically and prophylactically to manage oral and dental infections. The emergence of resistant bacterial strains due to overuse of antibiotics is a cause for worldwide concern.1 How and what GDPs prescribe is limited by the Dental Practitioners Formulary (DPF).2 In 1997, GDPs issued >3.5 million antibiotic prescriptions, which represent 7% of all the antibiotics prescribed in the community.3 Inappropriate prescribing by dentists could therefore play a significant part in the emergence of resistant strains. Our study investigated the prescribing of antibiotics, by analysis of prescriptions, issued by a large population of National Health Service (NHS) GDPs in England.


    Materials and methods
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
All adult dental prescriptions for antibiotics issued by GDPs from 10 Health Authorities (HAs) in February 1999 were included in the study. Liverpool, Wirral, Oxfordshire, Buckinghamshire, North Tyneside, Northumberland, Newcastle, Nottingham, North Nottinghamshire and Sheffield HAs were selected to provide a geographical spread of rural and urban areas and covering 10% of the total number of dentists working in the General Dental Services in England. The data collected from each prescription were the antibiotic prescribed, dose, frequency and duration in days.


    Results
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
A total of 17007 prescriptions were analysed. The antibiotics prescribed are shown in Table IGo. The majority of prescriptions (90.9%) were for generic antibiotics, with amoxycillin and metronidazole the most commonly prescribed (78%). Combinations of two or three antibiotics were prescribed in 5.6% of prescriptions, with 4% being for a combination of amoxycillin and metronidazole. Other combinations included penicillin and metronidazole, metronidazole and clindamycin, amoxycillin with metronidazole and penicillin, amoxycillin with clindamycin, and amoxycillin with penicillin.


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Table I. The number and percentage of the total number of prescriptions (n = 17007) for each of the antibiotics prescribed by GDPs in 10 English health authorities in February 1999
 
Detailed analysis of the most commonly prescribed antibiotics, shown in Table IIGo, demonstrated a wide variation in the doses employed, frequencies of prescription and duration of the course. Many of the prescriptions fell outside the recommendations of the DPF in terms of dose and frequency for the antibiotic prescribed: 44% of prescriptions for amoxycillin, 33% for metronidazole, 87% for penicillin and 42% for erythromycin.


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Table II. Details of the prescriptions for the most commonly prescribed antibiotics by GDPs in 10 English health authorities in February 1999
 

    Discussion
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 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
The majority of prescriptions (78%) issued were for amoxycillin or metronidazole. The recommendation of the DPF for most dental infections is phenoxymethylpenicillin four times daily, at a dose of 500 mg increased to 750 mg for severe infections.2 Only 1.2% of the prescriptions in this study were for penicillin at these doses and frequency. Recent studies showed, however, that the main isolates from dental abscesses are a complex mixture of facultative and anaerobic bacteria, often resistant to penicillin, justifying the use of amoxycillin or metronidazole.4

Erythromycin (base) in the treatment of dental infections is ineffective due to poor absorption and rapid emergence of resistant strains.5 It is only recommended for patients allergic to penicillin.2

Combinations of antibiotics are only indicated in the treatment of severe infections, with the DPF recommending phenoxymethylpenicillin (or erythromycin) with metronidazole.2 Within this study, most were combinations of amoxycillin and metronidazole.

The wide range of doses, frequencies and duration of all the antibiotics prescribed, many outside the recommendations of the DPF, was a major cause for concern. Antibiotics should be prescribed at the correct frequency, dose and duration so that the MIC is exceeded, and side effects and the selection of resistant bacteria are prevented. Although recommendations are given in the DPF on doses and frequencies, practitioners are only advised, with most antibiotics, to refrain from unduly prolonged courses.2 There is evidence that short courses of antibiotics, with appropriate clinical treatment, are adequate for the resolution of dental infections.6 Prolonged courses of antibiotics evident in this study, for periods up to 21 days, could be harmful by selecting resistant bacteria and abolishing colonization resistance.7 Large doses of amoxycillin (500 mg, 750 mg) and metronidazole (400 mg, 600 mg) in this study are contraindicated because absorption using the standard doses is therapeutically effective.4 However, the two-dose 3 g regimen for amoxycillin has been shown to be effective in specific situations.8

Our investigation showed that there is inappropriate prescribing of antibiotics within NHS general dental practice. To prevent the further development of antibiotic resistance, GDPs need clear guidelines and educational initiatives on prescribing of antibiotics. Recently published guidelines give advice on the recommended antibiotic, the dose, frequency and duration for specific clinical situations.9 This, with a possible revision of the DPF, may improve antibiotic prescribing in general dental practice.


    Acknowledgments
 
We thank the Prescription Pricing Authorities for providing the prescriptions and the NHS National Primary Dental Care Research and Development Programme for funding this study.


    Notes
 
* Corresponding author. Tel: +44-151-924-1934; Fax: +44-1704-872514; E-mail: NikolausPalmer{at}compuserve.com Back


    References
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
1 . Anonymous. (1997). Monitoring and management of bacterial resistance to antimicrobial agents: a World Health Organization symposium, Geneva, Switzerland, 29 November–2 December 1995. Clinical Infectious Diseases 24, Suppl. 1, S1–176.[ISI][Medline]

2 . The Royal Pharmaceutical Society of Great Britain and The British Medical Association. (1998). Dental Practitioners Formulary 1998. In British National Formulary No. 36. The Royal Pharmaceutical Society of Great Britain and the British Medical Association, London.

3 . Standing Medical Advisory Committee Sub-Group on Antimicrobial Resistance. (1998). The Path of Least Resistance. Department of Health, London.

4 . Lewis, M. A., Parkhurst, C. L., Douglas, C. W., Martin, M. V., Absi, E. G., Bishop, P. A. et al. (1995). Prevalence of penicillin resistant bacteria in acute suppurative oral infection. Journal of Antimicrobial Chemotherapy 35, 785–91.[Abstract]

5 . Quayle, A. A., Russell, C. & Hearn, B. (1987). Organisms isolated from severe odontogenic soft tissue infections: their sensitivities to cefotetan and seven other antibiotics, and implications for therapy and prophylaxis. British Journal of Oral and Maxillofacial Surgery 25, 34–44.

6 . Martin, M. V., Longman, L. P., Hill, J. B. & Hardy, P. (1997). Acute dentoalveolar infections: an investigation of the duration of antibiotic therapy. British Dental Journal 183, 135–7.[ISI][Medline]

7 . Longman, L. P. & Martin, M. V. (1991). The use of antibiotics in the prevention of post-operative infection: a re-appraisal. British Dental Journal 170, 257–62.[ISI][Medline]

8 . Lewis, M. A., McGowan, D. A. & MacFarlane, T. W. (1986). Short-course high-dosage amoxycillin in the treatment of acute dento-alveolar abscess. British Dental Journal 161, 299–302.[ISI][Medline]

9 . Royal College of Surgeons of England, Faculty of General Dental Practitioners (UK). (2000). Adult Antimicrobial Prescribing in Primary Care for General Dental Practitioners. Royal College of Surgeons of England, London.

Received 5 June 2000; returned 3 August 2000; revised 30 August 2000; accepted 12 September 2000