Antibiotics and Common Infections (1999)


Many common infections will resolve without the need for antibiotics, so when do we need to prescribe antibiotics and which ones should we use? In 1999, children antibiotics were given for acute otitis media more often than for any other condition seen in General Practice. Sore throat was also a common reason for prescribing in adults and children, and bronchitis may have been top of the list for prescribing antibiotics in adults.

This information page will look at these conditions and examine whether antibiotics change the course of the illness.

Bacterial resistance in the population is an increasing cause for concern in the UK and worldwide, and excessive use of antibiotics is believed to be an important factor in this process. Antibiotics also carry a risk to the individual patient of immediate side effects, such as rashes, diarrhoea and thrush.

In 2006 MEREC published a set of bulletins on upper respiratory infections, including pictures generated by Visual Rx in the section on Sinusitis.

2009 UPDATE: The limited benefit of antibiotics in preventing rare but serious complications (such as quinsy and mastoiditis) was highlighted in a National Prescribing Centre bulletin.

Acute Otitis Media

The peak incidence for acute ear infections is between 6 and 15 months, and there is no consensus on the best treatment; the rate of antibiotic usage in 1999 varied from 31% in the Netherlands to 98% in the USA and Australia.

Two reviews were published in the BMJ in 1997 examining the trials that had compared an antibiotic with placebo for treatment of acute otitis media (Del Mar 1997, Froom 1997). Both reviews concluded that most children would get better without antibiotics. If 20 children are given antibiotics for acute otitis media, 18 would be free from pain after two to seven days in comparison with 17 who would have been pain-free without antibiotics in the same time period. Moreover one extra child would also suffer a rash or diarrhoea if antibiotics were used.

Very few cases of mastoiditis were reported in children in either the antibiotic treated groups or the controls.

There was no clear cut picture as to which children would be more likely to benefit from antibiotic treatment, but one study suggested that younger children and those with previous episodes or bilateral acute otitis media were less likely to get better quickly with placebo treatment. (Burke P, Bain J, Robinson D, et al. Acute red ear in children: controlled trial of non-antibiotic treatment in general practice. BMJ 303:558-562, 1991). This is now further supported by more recent studies detailed on this site in the Ear infections section.

A possible approach to prescribing for acute otitis media is to discuss the evidence with parents (see the handout that we used) and to check that the child is being given a full dose of Paracetamol for their age. In those children who are not particularly ill and who are not prone to recurrent infections many parents may be happy not to use antibiotics. If the parents are keen for a prescription it can be given with the advice to defer cashing it at the chemist for 24 to 48 hours as the child may well be better by this time.

This approach was successfully adopted in our practice and it has been possible to achieve a considerable reduction in antibiotic usage for acute otitis media as a consequence. [Cates CJ. An evidence based approach to reducing antibiotic use in children with acute otitis media: controlled before and after study. BMJ 1999;318:715-716].

The results of five years of follow-up after our change in practice are documented in the Evidence Based Medicine Journal and a pdf can be found here.

Sore Throat

Many patients who present with sore throat are suffering from viral rather than bacterial infections and the worst looking purulent tonsillitis may be due to Glandular Fever. For this reason Amoxycillin should NOT be used for throat infections as it may cause an unpleasant rash if the patients’ throat infection is due to Glandular Fever. Penicillin V is still the first choice if an antibiotic is to be used for tonsillitis, as so far the Streptococcus remains fully sensitive to penicillin.

A summary of the evidence relating to antibiotics and sore throat in 2006 (which included data from 27 randomised controlled trials) came to the following conclusions:

“Antibiotics confer relative benefits in the treatment of sore throat. However, the absolute benefits are modest. Protecting sore throat sufferers against suppurative and non-suppurative complications in modern Western society can only be achieved by treating many with antibiotics, most of whom will derive no benefit. In emerging economies (where rates of acute rheumatic fever are high, for example), the number needed to treat may be much lower for antibiotics to be considered effective. Antibiotics shorten the duration of symptoms by about sixteen hours overall.”

(Del Mar CB, Glasziou PP, Spinks AB. Antibiotics for sore throat. Cochrane Database of Systematic Reviews 2006, Issue 4.)

Acute Bronchitis

An article in the Drugs and Therapeutics Bulletin has suggested that patients with signs of lower respiratory tract infection should be treated aggressively with antibiotics. (Antibiotic treatment of adults with chest infection in general practice. DTB 1998;36:68-72)

Should antibiotics be given to other patients with acute bronchitis? A systematic review seeking to answer this question identified 750 patients (aged 8 to 65) included in randomised controlled trials to compare antibiotic treatment with placebo. The antibiotics used were erythromycin, co-trimoxazole and doxycycline. The benefit in terms of average duration of symptoms is about half a day less cough or sputum production if antibiotics are given, and in some studies the cough continued for more than five days whether antibiotics were given or not. On average patients given antibiotics tended to return to work 0.75 days earlier than those on placebo.

The number needed to harm with adverse effects was 15 patients which is close to the number needed to treat of 13 to avoid one case of no improvement at follow-up when assessed by the physician. (Becker L, Glazier R, McIsaac W, Smucny J. Antibiotics for Acute Bronchitis (Cochrane Review). In: The Cochrane Library, Issue 3, 1998. Oxford: Update Software.)

Similarly balanced figures were obtained from another systematic review on this subject in the BMJ this summer, with estimates of 11 for the number needed to treat and 13 for the number needed to harm with an antibiotic prescription.

(Fahey T, Stocks N, Thomas T. Quantitative systematic review of randomised controlled trials comparing antibiotic with placebo for acute cough in adults. BMJ 1998; 316: 906-910)


The available data shows that the benefit of antibiotics in many patients presenting with sore throat, earache, cough and sinus pain is very limited. This presents two challenges for us in general practice. How can we target treatment to those few patients who will benefit most from an antibiotic, and how can we reduce our prescribing for those who do not.

There is precious little evidence to help us decide which patients will benefit from antibiotic prescriptions so at present we have to continue to use clinical judgement (such as whether the patient has a high fever and looks toxic). Throat swabs are of limited use due to the background carriage rate of Streptococcus in healthy individuals and the time taken to receive the results of the test.

It is certainly worth checking what the patient is expecting, as in general we tend to assume that the patient wants an antibiotic when this may not be the case. It is also helpful to have written information explaining the limited benefits of antibiotic prescriptions and the problems of side effects and increasing antibiotic resistance that can be given to the patient.

A copy of the otitis media handout is included on this site, and you are welcome to adapt this for you own use (tailored to your practice population) and perhaps ask some of your patients to comment on the wording before putting it out for general use. The data presented in this paper may be used as a basis for handouts.

Deferred prescriptions have been found to be useful in acute otitis media which resolves quickly (often within 48 hours) as the parents can be involved in the decision as to whether the child is given the antibiotic, depending on how quickly the symptoms resolve. It is not known how successful the same strategy would be in bronchitis, since the resolution of cough if often fairly slow.

Final Points

Discuss in advance any changes that you plan to make with the whole practice; patients are very quick to exploit differences between partners.
Start with one area (such as acute otitis media in children) and see if you can demonstrate a change; the Medicines Management department at your Health Authority may be able to help with the collection and analysis of PACT data for you, or you can use your own level 3 PACT data.
In the long run not giving an antibiotic prescribing can decrease the reattendance rate, as shown by the study in Southampton. (Little P et al. Reattendance and complications in a randomised controlled trial of prescribing strategies for sore throat: the medicalising effect of prescribing antibiotics. BMJ 1997;315:350-353)
Finally don’t accept uncritically everything that drug reps tell you; their job is to persuade you to use their product and there is sometimes another side to the story!