Updated: May 6
Dear friends, Welcome back to our TGIF Dr Euan blog!
Every time we frequent a petrol station or 711 store, we are often faced with an array of various lozenges/mints /clorets in a blaze of colour and decor at the payment counter. Many a time, we do buy a pack/box to try out. For me, I rather like the strong tasting "Fisherman's Friend" label.
The many varied colourful throat lozenges available to the public
But like me, have you ever wondered if these remedies actually work? Do they alleviate symptoms of sore throat? Cough? Discomfort? Or are they just sweets and candy?
Well, this week, we are going to take a closer look into this ..... read on!
Q: Do throat lozenges work?
Throat lozenges generally contain painkillers, antibacterial agents, antitussives, pectin, menthol and/or eucalyptus. Let us take a closer look at each ingredient to see how effective they are in reducing sore throat symptoms.
Benzydamine hydrochloride and flurbiprofen are painkillers that belong to the group known as NSAIDs (non-steroidal anti-inflammatory drugs) that help reduce inflammation and swelling.
A number of good-quality studies have shown that flurbiprofen lozenges and benzydamine hydrochloride is given as a spray or gargle provide effective relief from sore throat symptoms, including difficulty in swallowing.
Amylmetacresol, cetylpyridinium chloride, dichlorobenzyl alcohol and hexylresorcinol are antibacterial agents that help fight against disease-causing bacteria.
But the majority of sore throats are caused by viral infections rather than bacterial, so for the most part antibacterial agents in lozenges aren't going to help.
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 numbing the mouth and throat during minor surgical procedures, or when a tube must be inserted into the windpipe. Benzydamine hydrochloride and hexylresorcinol also have local anaesthetic properties.
Antitussives (cough suppressants)
Pholcodine and dextromethorphan hydrobromide are antitussives that are intended to help suppress dry, unproductive (non-phlegmy) coughs, which can contribute to making your throat sore. But a wide-scale review of trials testing antitussives (mainly dextromethorphan) found that they were 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 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, thanks to its ability to chemically trigger cold-sensitive receptors in the skin. But the effect of nasal decongestion from menthol is subjective – studies show that although people feel decongested after inhaling menthol vapour, there's no actual improvement in the nasal airway when airflow is measured.
Just like menthol, eucalyptus is thought to act as a nasal decongestant. However, there's a lack of controlled, clinical studies to support its effectiveness.
Pectin is 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 would.
Next, how about treating the common "cough & cold"?
Q: Can throat lozenges help cure 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.
Different cough sweets, mints and lozenges available in a convenience store
They all have one or more of the following ingredients in common:
Echinacea is 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, the overwhelming majority of products haven't been tested in clinical trials.
A Cochrane review of echinacea found that some preparations might be effective for the early treatment of colds in adults, but results do not appear to be consistent. Beneficial effects of other preparations might exist but have not been substantiated in good-quality randomised trials.
Vitamin C (ascorbic acid)
Vitamin C appears in throat lozenges in various forms, including sodium ascorbate and calcium ascorbate di-hydrate. It is thought that it can help reduce the duration of the common cold. But a Cochrane review of vitamin C found that it didn't show any benefit in doses up to 4g daily. The dose of vitamin C in individual throat lozenges sampled by CHOICE ranged from 10mg to 100mg.
Zinc is thought to reduce symptoms of the common cold, including a sore throat. A 1999 Cochrane review found that evidence was inconclusive as to whether zinc lozenges were an effective treatment for symptoms of the common cold. Since then though, several new studies have shown that treatment with zinc lozenges does significantly decrease cold duration. It's likely that the results are conflicting because the dose and formulation of the zinc used has an influence over effectiveness.
So, the next time you pay at the counter at 711 or at ESSO Cheers / Calex / SHELL gas stations, have a look at the contents/ingredients of the pack of lozenges before you buy it!
Also, if you have a persistent/chronic sore throat that does not go away, after 2 weeks, please do consult your GP or ENT Specialist to get it checked out. At our ENT clinic, we offer a thorough check-up (history and examination) with a fibre-optic naso endoscopy to have a detailed look and see if there are any hidden/more sinister causes for your persistent sore throat, including any signs of throat cancer.
Photo showing an example of a throat exam and Naso-endoscopy with camera in our clinic (courtesy of Euan's ENT Surgery & Clinic)
Here are some useful references you may want to look up for more discussion on this topic.
Have a great and relaxing weekend, folks!
1) Maheshwari R., Jain V., Ansari R., Mahajan S.C., joshi G. A Review on lozenges. British Biomedical Bulletin. 2013; 1(1): 35-43.
2) Shinde G., Kadam V., Kapse G.R., Jadhav S.B., Zameeruddin Md., Bharkad B.A:Review on lozenges. “Indo American Journal of Pharmaceutical Research. 2014; 4(1):566-571.
3) Pothu R., Rao Y. Lozenges Formulation and Evaluation. International Journal of Advances in Pharmaceutics. Research. 2014; 5(5):290 – 298.
4) Kaur R., Kaur S. Role of polymers in drug delivery. Journal of Drug Delivery and Therapeutics, 2014; 4(3):32-36. https://doi.org/10.22270/jddt.v4i3.826
5) Loyd. V. Ansel Pharmaceutical Dosage forms & Drug delivery System. Chewable Lozenge. 8thedition. New Delhi (India) Pvt. Ltd. 2007; 246.
6) Aulton E. M. Aulton pharmaceutics. Compressed lozenges. 3rdedition.Elsevier. 2007; 457.
7) Pothu R., Rao Y. Development and In-Vitro Evaluation of Nicotine Troches for Smoking Cessation. Asian Journal Pharmaceutical and Clinical Research. 2014; 7(2):68-75.
8) Modyala D., Srinivas P. Formulation, Evaluation and Characterization of Itraconazole Lozenges. International Science and Research Journal of Pharmceutical, Bioscience. 2014; 9(3):86-94.
9) Phaechamud T and Tuntarawongsa S. Clotrimazole Soft Lozenges Fabricated with Melting and Mold Technique. Research Journal of Pharmceutical, Bioscience. & Chemical. Science. 2010; 1(4):579- 587.
10) Patel M. Dasharath, Patel J. Rahul, Shah R.M., Patel N. Chhagan. Formulation and Evaluation of Diphenhydramine hydrochloride Lozenges for Treatment of Cough. World. Journal of Pharmaceutical Science. 2014; 3(5):822-835.
11) Kini R., Rathnanand M., Kamath D. Investigating the Suitability of Isomalt and liquid glucose as sugar substitute in the formulation of Salbutamol Sulfate hard candy lozenges. Journal of Chemical and Pharmaceutical Research. 2011; 3(4):69-75.
12) Nagoba S.N. Studies on candy Ketoconazole based Paedriatic tablet lozenges. International Journal of Research in Ayurveda & pharmaceutics. 2011; 2(1):239-243.
13) Rao K., Reddy V., N. Nagoba Shivappa, Ayshiya S., Zakaullah, Saran S V. Medicated lollipops for the treatment of Oral thrush in children.“International Journal of Life Science & Pharmceutics. Research. 2012; 1(1):95 -102..