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Alan Nathan considers the effectiveness of pastilles, lozenges, sprays and gargles for sore throat

Sore throat is treated OTC using one or more of the following approaches: stimulation of saliva production (demulcents); use of antimicrobials; local anaesthesia; anti-inflammatories.

Demulcents

Saliva produced by sucking lubricates and soothes inflamed tissues and washes infecting organisms away. All lozenges and pastilles stimulate saliva release and this is responsible for demulcents’ effectiveness.

Non-medicated glycogelatin-based demulcent pastilles such as glycerine, lemon and honey pastilles can be effective for a limited period. As they contain no medicament they can be taken as often as necessary to stop the throat feeling dry..

Products containing volatile oil and constituents such as eucalyptus oil and menthol produce a sensation of clearing blocked nasal and upper respiratory passages, and can relieve symptoms of upper respiratory tract infections, which often accompany sore throat. The main disadvantage of demulcents is their high sugar content, although there are some sugar-free products.

Antimicrobials

The bactericidal 2,4-dichlorobenzyl alcohol (DCBA), amylmetacresol, benzalkonium chloride, cetylpyridinium chloride, dequalinium chloride, hexylresorcinol and tyrothricin also have varying degrees of antifungal activity and activity against lipophilic viruses. But the main rhinoviruses responsible for the common cold are hydrophilic. A sore throat complicated by a secondary bacterial infection would usually be treated with a systemic antibiotic.

Antimicrobial lozenges are licensed for adults and children aged six or older, depending on product. Dosages are usually one sucked every two or three hours, with a daily maximum of from six to 12, again dependent on product.

Gargles licensed for sore throat also mainly contain antiseptics, often the same as in throat lozenges. Their main action is the mechanical removal of microbes from the pharynx, but levels of contamination are likely to be restored in a very short time.

Local anaesthetics

Benzocaine is included, together with tyrothricin, in one brand of throat lozenges. It is also the sole constituent in two brands of throat spray. Another throat spray contains 0.05 per cent lidocaine plus chlorhexidine, an antiseptic. Benzocaine sprays can be used every two or three hours up to eight doses daily in adults and children aged six and over. The brand containing lidocaine is licensed for adults and children from age 12. Anaesthetics in lozenges and sprays can cause sensitisation.

Anti-inflammatories

• Flurbiprofen The NSAID flurbiprofen is available as a lozenge formulation for the relief of sore throat, for adults and children from age 12 years. The dosage is one lozenge every three to six hours, to a maximum of five lozenges in 24 hours, for up to three days. The usual precautions for the use of NSAIDs apply.
• Benzydamine An oral rinse containing 0.15 per cent benzydamine hydrochloride is licensed for adults and children aged 12 and over. Dosage is 15ml as a rinse or gargle every one and a half to three hours for up to seven days. It has proven effective at treating some inflammatory conditions.

Effectiveness 

General

In a systematic review of controlled trials involving 22 non- antibiotic managements, their efficacy relative to placebo ranged from no effect to 93 per cent. Some of the studies reported that some non-antibiotic treatments may be more effective than antibiotics, although publication bias may have exaggerated the benefits.

Antimicrobials

A randomised controlled trial² was conducted with 310 patients to determine the analgesic properties of amylmetacresol/DCBA lozenges (Strepsils) versus placebo in the relief of acute sore throat caused by upper respiratory tract infections. Lozenges were taken as required for up to three days. Strepsils reduced soreness at five minutes after the first dose, persisting for two hours and were significantly superior to non-medicated lozenges at all assessment time points for the study duration.

A multicentre, randomised, double-blind, parallel group, placebo-controlled study³ involving 190 patients was conducted to determine the analgesic efficacy of two lozenges, one containing amylmetacresol/DCBA plus lidocaine, one containing hexylresorcinol and a placebo, in patients with acute sore throat due to upper respiratory tract infection. Subjective ratings of throat soreness, difficulty swallowing, swollen throat, numbing and sore throat relief were obtained up to two hours post dose. Both lozenges provided rapid and effective sore throat relief and were superior to placebo.

Benocaine

In a trial of 165 volunteers with acute, uncomplicated sore throat, participants received randomly and double-blinded either a benzocaine 8mg or a placebo lozenge4. Pain was assessed on a numerical visual rating scale, the primary outcome measure being the sum of the pain intensity differences over two hours. Significantly more patients in the benzocaine group achieved worthwhile pain relief than with placebo, although the number of patients with complete pain relief was very small. No adverse events were observed. The authors concluded that benzocaine lozenges were superior to placebo lozenges and a useful, well-tolerated treatment option to reduce painful pharyngeal discomfort.

Flurbiprofen

Several clinical trials^5,6,7,8 have concluded that flurbiprofen lozenges provide an effective and well-tolerated treatment for sore throat.

Benzydamine

A small trial⁹ concluded that benzydamine gargle was a safe and effective therapy for the symptoms of sore throat.

References available on request.