Antibiotics for sore throat

Background

Sore throat is a very common reason for people to present for medical care. Although it remits spontaneously, primary care doctors commonly prescribe antibiotics for it.

Objectives

To assess the benefits of antibiotics for sore throat.

Search strategy

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) and the Database of Abstracts of Reviews of Effects (DARE) (The Cochrane Library, 2006, issue 1) which contains the Acute Respiratory Infections Group's Specialized Register, MEDLINE (January 1966 to March 2006) and EMBASE (January 1990 to December 2005).

Selection criteria

Trials of antibiotic against control with either measures of the typical symptoms (throat soreness, headache or fever), or suppurative or non-suppurative complications of sore throat.

Data collection and analysis

Potential studies were screened independently by two authors for inclusion, with differences in opinion resolved by discussion. Data were then independently extracted from studies selected by inclusion by two authors. Researchers from three studies were contacted for additional information.

Main results

There were 27 studies with 12,835 cases of sore throat.

1. Non-suppurative complications
There was a trend for antibiotics to protect against acute glomerulonephritis, but there were insufficient cases to be sure. Several studies found antibiotics reduced acute rheumatic fever by more than two thirds (relative risk (RR) 0.22; 95% CI 0.02 to 2.08).

2. Suppurative complications
Antibiotics reduced the incidence of acute otitis media (RR 0.30; 95% CI 0.15 to 0.58); of acute sinusitis (RR 0.48; 95% CI 0.08 to 2.76); and of quinsy (peritonsillar abscess) compared to those taking placebo (RR 0.15; 95% CI 0.05 to 0.47).

3. Symptoms
Throat soreness and fever were reduced by antibiotics by about one half. The greatest difference was seen at about 3 to 4 days (when the symptoms of about 50% of untreated patients had settled). By one week about 90% of treated and untreated patients were symptom-free. The overall number need to treat to prevent one sore throat at day 3 was just under six (95% CI 4.9 to 7.0); at week 1 it was 21 (95% CI 13.2 to 47.9).

4. Subgroup analyses of symptom reduction
Analysis by: age; blind versus unblinded; or use of antipyretics, found no significant differences.
Analysis of results of throat swabs showed that antibiotics were more effective against symptoms at day 3, RR 0.58 (95% CI 0.48 to 0.71) if the swabs were positive for Streptococcus, compared to RR 0.78 (95% CI 0.63 to 0.97) if negative. Similarly at week 1, RRs 0.29 (95% CI 0.12 to 0.70) for positive, and 0.73 (95% CI 0.50 to 1.07) for negative swabs.

Authors' 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.