Prescribing Review - Antibacterial Drugs


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Various measures that prescribers can use to reduce unnecessary use of antibiotics have been trialled. A Cochrane review concluded that using several methods together, such as educational visits for doctors, patient education and delayed prescriptions for infections for which antibiotics are not immediately indicated, is more likely to reduce the incidence of antibiotic-resistant bacteria than trying a single method on its own.⁴ A patient information leaflet “Why no antibiotic?” is available through PRODIGY.⁵ Delayed prescribing can involve either providing a prescription and asking the patient not to redeem it unless symptoms persist, or asking the patient to return to the doctor for a prescription. The latter approach has been used effectively in practice, with many patients reporting that they have not needed to take antibiotics.⁶ Guidance for the management of common infections in primary care aims to help prescribers to identify those infections which require immediate treatment with an antibiotic, infections for which it would be safe to delay prescribing, and infections for which antibiotics are of no benefit.^3,7 This guidance also identifies which antibiotics would be most appropriate to prescribe for common infections. Antibacterial drugs should not be prescribed routinely for the common cold, acute sinusitis, acute otitis media in children, sore throats and acute bronchitis in otherwise healthy, non-elderly adults.¹ One of the difficulties for prescribers is to identify the small number of patients with these conditions who would benefit from an immediate antibiotic. The presence of systemic illness or the occurrence of several severe signs and/or symptoms can help to distinguish patients who require antibiotics. For example patients with sore throat and at least 3 of the 4 Centor criteria (history of fever, purulent tonsils, cervical adenopathy, and absence of cough) may benefit more from antibiotics.³

In patients with exacerbations of chronic obstructive pulmonary disease, a history of more purulent sputum indicates that antibiotics should be prescribed.⁸ Patients with exacerbations without more purulent sputum do not need antibiotics unless a chest x-ray shows consolidation or there are clinical signs of pneumonia. A meta-analysis of trials of antibiotics in children with acute otitis media found that they were of most benefit in children younger than 2 years of age with bilateral acute otitis media, and in children with both acute otitis media and a draining ear (otorrhoea). For most other children with mild disease a policy of watchful waiting would be justified.⁹ The National Institute for Health and Clinical Excellence is preparing a guideline on assessment and initial management of feverish illness in children younger than 5 years .¹⁰ The guideline adopts a traffic light approach for healthcare professionals to use in assessing signs and symptoms in children greater than 3 months old, and will provide guidance on when to make a referral to paediatric specialist care.

Most cases of acute infective conjunctivitis are self limiting and delayed prescribing of a topical antibiotic such as chloramphenicol is probably the most appropriate management strategy .¹¹ Patients should be asked to return if a red eye does not show signs of improvement within a few days or if symptoms worsen. Before prescribing an antibiotic, more serious causes of a red eye (acute glaucoma, uveitis and keratitis) should be excluded. A full examination of the eye is necessary if any of the following are present: moderate to severe eye pain, marked redness of the eye or reduced visual acuity.¹²
The numbers of new diagnoses at genitourinary medicine clinics rose by 3% between 2004 and 2005 (from 767,785 in 2004 to 790,443 in 2005).¹³ Genital chlamydia trachomatis is the most common sexually transmitted infection in England: about 10% of women and men aged under 25 years are positive on screening.¹⁴ The National Chlamydia Screening Programme (NCSP) is being rolled out to all Primary Care Trusts in 2007. The NCSP is part of a broader sexual health strategy that will require local agencies to work together. Currently only a quarter of GPs in Phases 1 and 2 of the NSCP are participating in chlamydia screening. Doxycycline 100mg twice daily or oxytetracycline 500mg four times daily for 7 days is the first choice for chlamydia infection. Erythromycin and ciprofloxacin are less effective.³

Prescribing data
There is more prescribing of antibacterial drugs in the northern Strategic Health Authorities (SHAs) and the South (Chart 3), however over the last 3 years prescribing has decreased in these SHAs while there has been very little change in prescribing in the South. Public campaigns to reduce demand for unnecessary antibacterial prescribing are likely to be beneficial in all SHAs, although it is difficult to demonstrate the impact of such educational campaigns.

Variation Between Strategic Health Authorities in Prescribing of Antibacterial Drugs (Chart 3)

Cost for 5 Days Treatment

Penicillins are the most commonly prescribed antibiotics (18 million items, £62.2 million for year to September 2006). In the past 5 years penicillin items have decreased by 2.6% while their cost has increased by 15%. There are 10.4 million amoxicillin, 3.4 million flucloxacillin, 2.3 million phenoxymethylpenicillin and 1.7 million co-amoxiclav items. The corresponding costs were £19.4 million, £20.2 million, £7.7 million and £13.0 million. Flucloxacillin items have increased by 14% over the last 5 years while cost increased by 62%. A higher incidence of skin infections such as impetigo is unlikely and there is no obvious explanation for the increased use of flucloxacillin. Prescribing of topical antimicrobial products has remained relatively constant. Co-amoxiclav items have hardly changed (0.6% increase) while cost decreased by 23%. Items for phenoxymethylpenicillin and amoxicillin have decreased by 2.7% and 6.5% respectively, although cost has increased by 27% and 21% respectively.

Macrolides are the second most commonly prescribed group of antibiotics (4 million items, £32.5 million in the year to September 2006). Erythromycin accounted for 3 million items and £16.8 million, clarithromycin for 0.8 million items and £12.3 million and azithromycin for 0.1 million items and £3.3 million. Over the last 5 years prescribing of these drugs has fallen by 8% while cost has risen by nearly 15%. Erythromycin items have decreased by 14% while clarithromycin items have increased by nearly 12%.

Cephalosporin prescribing has risen over the last 5 years by 4% while cost increased by nearly 12% (3.2 million items, £16.7 million in the year to September 2006). The most commonly prescribed cephalosporin is cefalexin (2.3 million items) followed by cefaclor (0.4 million items). Cost is £8.6 million and £3.5 million respectively.

Tetracycline items and cost have remained little changed over the last 5 years (2.5 million items, £21.9 million, year to September 2006). Oxytetracycline and doxycycline are most often prescribed (0.9 and 0.8 million items respectively). Minocycline accounts for 0.4 million items. More is spent on minocycline (£8.3 million) than on either oxytetracycline or doxycycline (£5.4 million and £3.8 million respectively). Minocycline should not be used for acne due to the risk of rare but serious adverse effects and its high cost.¹⁵

Quinolones are prescribed less often than the other commonly used groups of antibacterial drugs (1.2 million items, £7.7 million in the year to September 2006). Items increased by 12% but cost fell by 58% over the past 5 years. Ciprofloxacin accounts for 87% of all quinolone items and 61% of cost (1.1 million items, £4.7 million in the year to September 2006).

Trimethoprim items increased by just less than 6% while cost has increased by more than 70% in the past 5 years (2.9 million items, £3.9 million year to September 2006). The prices of trimethoprim 100mg and 200mg tablets increased in April 2005 with the introduction of Category M in Part VIII of the Drug Tariff. Co-trimoxazole items have increased by over 13% in the past 5 years (53,400 items, £0.62 million year to September 2006).

Antibacterial skin preparations account for 1.6 million items and £7.5 million in the year to September 2006. The most commonly prescribed preparations contain fusidic acid (1.0 million items costing £2.8 million). These totals exclude topical corticosteroid containing antibacterial drugs for which there were 4.7 million items costing £19.8 million in the year to September 2006. 39% of all items for topical corticosteroid preparations contain antimicrobial drugs (antifungal and antibacterial agents), which suggests that there is unnecessary prescribing of antibiotics in some cases.

1. MeReC Bulletin. The management of common infections in primary care. National Prescribing Centre. December 2006
   www.npc.ppa.nhs.uk/MeReC_Bulletins/MeReC_Bulletin_Vol17_No3_Intro.htm.
   
2. Health Protection Agency. Trends in antimicrobial resistance in England and Wales, 2004-2005. December 2006.
   www.hpa.org.uk/publications/2006/antimicrobial_resistance/AMR_report_2004_2005.pdf
   
3. Health Protection Agency. Management of infection guidance for primary care for consultation and local adaptation. Amended May 2006. www.hpa.org.uk/infections/topics_az/primary_care_guidance/Antibiotic_guide_250506.pdf
   
4. Arnold SR, Strauss SE. Interventions to improve antibiotic prescribing practices in ambulatory care. Cochrane Database of Systematic Reviews 2005, Issue 4. Art. No.: CD003539. DOI: 10.1002/14651858.CD003539.pub2
   
5. Clinical Knowledge Summaries (PRODIGY Patient Information Leaflet). Why no antibiotic? NHS National Library for Health. Accessed January 2007.
   www.prodigy.nhs.uk/patient_information/pils/antibiotics_why_no_antibiotic.htm
   
6. Little P. Delayed prescribing of antibiotics for upper respiratory tract infection. BMJ 2005; 331: 301-302
   
7. Clinical Knowledge Summaries (PRODIGY guidance). NHS National Library for Health. Accessed January 2007. www.prodigy.nhs.uk/
   
8. Chronic obstructive pulmonary disease. NICE clinical guideline 12, February 2004.
   www.nice.org.uk/guidance/CG12/quickrefguide/pdf/English
   
9. Rovers MM, Glasziou P, Appelman CL et al. Antibiotics for acute otitis media: a meta-analysis with individual patient data. Lancet 2006; 368: 1429-1435
   
10. Feverish illness in children consultation. NICE guideline, November 2006.
    www.nice.org.uk/page.aspx?o=388071
    
11. Everitt HA, Little PS, Smith PWF. A randomised controlled trial of management strategies for acute infective conjunctivitis in general practice. BMJ, doi:10.1136/bmj.38891.551088.7C (published 17 July 2006)
    
12. Clinical Knowledge Summaries (PRODIGY guidance). Conjunctivitis – infective. NHS National Library for Health. Accessed January 2007. www.prodigy.nhs.uk/conjunctivitis_infective/
    
13. Health Protection Agency. 2005 STI data. Accessed January 2007.
    www.hpa.org.uk/infections/topics_az/hiv_and_sti/epidemiology/datatables2005.htm
    
14. NCSSG. New frontiers: annual report of the National Chlamydia Screening Programme in England 2005/06. Health Protection Agency 2006.
    www.hpa.org.uk/publications/2006/NCSP/NCSP_annual_report.pdf
15. McManus P, Iheanacho I. Don't use minocycline as first line oral antibiotic in acne. BMJ 2007; 334: 154
    

SUMMARY

• Resistance to antibacterial agents is a continuing public health issue. They should not be used more than necessary.
• A clear indication should be established before prescribing a quinolone, cephalosporin or co-amoxiclav. Avoid using as first-line choice for infections where standard and less expensive antibiotics remain effective.
• Where there is no immediate need for an antibiotic, a delayed prescription is an effective method for managing the patient’s expectations and reducing unnecessary use of antibiotics.
• Patient information leaflets are available for managing patients with common self limiting infections.
• In patients with acute infective conjunctivitis more serious causes of a red eye (acute glaucoma, uveitis and keratitis) should be excluded before deciding whether to prescribe an antibiotic. Most cases of acute infective conjunctivitis are self limiting.
• Prescribing of minocycline for acne should be avoided.
• The number of new diagnoses at GU clinics is increasing year on year, with genital chlamydia trachomatis the most common. About 10% of women and men aged under 25 years are positive for genital chlamydia trachomatis on screening.