Throat lozengers

Relief or rip-off?
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  • Updated:3 May 2007



What’s in them?

Throat lozenges generally contain at least one of the following ingredients:

  • Anaesthetics: benzocaine, lignocaine hydrochloride. Benzydamine hydrochloride, see Painkillers (below) and hexylresorcinol, see Antibacterials (below) also have local anaesthetic properties. Local anaesthetics numb the area they’re in contact with and provide temporary relief from soreness. Lignocaine hydrochloride and benzocaine are used widely in medical and dental practice for locally numbing the mouth and throat for minor surgical procedures or when a tube must be inserted into the windpipe.
  • Painkillers: benzydamine hydrochloride, flurbiprofen. These painkillers belong to the group known as NSAIDs (non-steroidal anti-inflammatory drugs) that help reduce swelling. A number of good-quality studies have shown that flurbiprofen lozenges and benzydamine hydrochloride given as a spray or gargle provide effective relief of sore throat symptoms, including difficulty in swallowing.
  • Antibacterials: amylmetacresol, cetylpyridinium chloride, dichlorobenzyl alcohol, hexylresorcinol. As the name implies, antibacterials help fight against bacteria. But the majority of sore throats are caused by viral, not bacterial, infections (see Sore throats: the causes). So for the most part, antibacterials in lozenges aren’t going to help. Lemsip even concedes this on its LEMSIP Max Sore Throat Anaesthetic Antibacterial Lozenges packaging: “The presence of the antibacterial agent in this product has not been shown to have beneficial effect on the severity or duration of a sore throat.”
  • Antitussives (cough suppressants): pholcodine, dextromethorphan hydrobromide. Antitussives are intended to help suppress dry, unproductive coughs, which can contribute to making your throat sore. A Cochrane review of trials testing antitussives (mainly dextromethorphan), however, found that they appeared no more effective than a placebo for treating coughs in most cases. And a much higher concentration of dextromethorphan was used in the trials than is found in throat lozenges.
  • Menthol/peppermint. Menthol is made synthetically or obtained from mint oils — it’s the component of peppermint oil that’s thought to be responsible for most of its therapeutic properties. It gives a cooling and soothing sensation when you inhale or eat it due to its ability to chemically trigger cold-sensitive receptors in the skin. But the sensation of nasal decongestion from menthol is a subjective perception — studies show that although people feel decongested after inhaling menthol vapour, there’s no actual improvement in the nasal airway when airflow is measured.
  • Eucalyptus. Just like menthol, eucalyptus is thought to act as a nasal decongestant. However there’s a lack of controlled, clinical studies.
  • Pectin. It’s commonly used as a thickening agent in foods like jam and jelly. In throat lozenges it’s used to coat the throat, and in doing so has a soothing effect in much the same way as a teaspoon of honey.

    The tables lists throat lozenge products and their ingredients.

Please note: this information was current as of May 2007 but is still a useful guide today.

Can they help your cold?

Many throat lozenges claim to have effects that extend beyond soothing a sore throat to the relief of cold and flu symptoms generally. They all have one or more of the following ingredients in common:

Echinacea. It’s thought to help boost the immune system and alleviate symptoms of the common cold. Its preparations can differ greatly depending on the type and parts of the plant used and the manufacturing methods, however, and the overwhelming majority of products haven’t been tested in clinical trials. A Cochrane review of trials investigating the effectiveness of echinacea for preventing and treating common colds found that some preparations might be effective for the early treatment of colds in adults, but results aren’t consistent. Beneficial effects of other preparations might exist but haven’t been shown in good-quality trials.

Vitamin C (ascorbic acid) appears in throat lozenges in various forms, including sodium ascorbate and calcium ascorbate dihydrate. It’s thought that it can help reduce the duration of the common cold. But a Cochrane review of vitamin C found that the trials in which it was introduced at the onset of colds as therapy didn’t show any benefit in doses up to 4 g daily. The dose of vitamin C in individual throat lozenges in our sample ranged from just 10 mg to as much as 100 mg.

Zinc. It’s thought to reduce symptoms of the common cold, including a sore throat. A 1999 Cochrane review concluded that evidence was inconclusive as to whether zinc lozenges were an effective treatment for symptoms of the common cold. Since then several new studies have shown that treatment with zinc lozenges significantly decreased cold duration. It’s likely that the results are conflicting because the dose and formulation of the zinc used has an influence over effectiveness, and these things differed between trials. Zinc in the lozenges in our sample is from zinc gluconate at a dose of up to 3.2 mg per lozenge. The dosage of zinc (from zinc gluconate) used in the trials, effective or not, ranged from 13.3 to 23 mg.

Throat therapy

Taking paracetamol or aspirin (for adults) is an effective way to relieve the pain and discomfort of a sore throat. But if you’d rather not take any medication, the following might also help:

  • Drink warm liquids. Hot water with honey and lemon is a time-tested remedy.
  • Gargle with warm salt water (half a teaspoon of salt in one cup of water).
  • Suck on ice.
  • Use your air humidifier, if you have one.

A sore throat usually resolves itself within three to four days, and it’s unusual for one to last beyond a week. If it persists, or your symptoms include severe difficulty swallowing or breathing, a fever or tender or swollen lymph glands in the neck, see your doctor.

Sore throat: the causes

  • Most sore throats are caused by viruses, and cold and flu viruses are the main culprits. If your sore throat is a minor part of a typical cold (with a runny nose, blocked ears, cough and similar symptoms), it’s likely to be caused by a viral infection. Viral sore throats are contagious and you can pass them on to someone by coughing and sneezing.
  • Sore throats can also be caused by infection by bacteria, most commonly streptococcus (this infection is referred to as ‘strep throat’). Because strep throat can occasionally lead to rheumatic fever it’s best treated with antibiotics, but it needs a lab test to accurately diagnose it. Viral sore throats, on the other hand, won’t respond to antibiotics.
  • Not all sore throats are caused by infection. Hay fever and other allergies may irritate the sinuses, causing post-nasal drip (drainage that runs down the back of your throat) and irritation, especially at night. Low humidity, smoking and air pollution can all make the throat sore. And people who breathe through their mouth at night because of nasal congestion often get a sore throat that improves as the day progresses.

What's a Cochrane review?

Cochrane reviews are systematic reviews of healthcare-related research reports on particular topics that have been published in hundreds of journals around the world. They explore the evidence for and against the effectiveness and appropriateness of treatments (medications, surgery, education, etc) in specific circumstances. They differ from other systematic reviews in that they use a predefined explicit methodology, and they’re updated regularly. They’re known internationally as sources of high-quality, reliable health information.



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