Do cough syrups cure a cough? No, they don’t, simply because a cough is not a disease. It’s a symptom of an underlying disorder, a reflex response to irritation of the airways because of triggers such as throat and lung infection, excess secretions in the airways and lung, allergens or environmental irritants such as dust and smoke, among others.
Yet millions swallow several spoonfuls of cough and cold formulations each day in the misplaced belief that it will make them better, making cough syrups among the top five medicines sold in India.
Using cough suppressants can do more harm than good because it does not cure the underlying disease. “Suppressing or controlling cough is clinically irrational without first determining and then treating the disorder. Much like fever and diarrhoea, a cough is an early sign to draw attention to an underlying disease,” said drug expert Dr Chandra M. Gulhati, editor, Monthly Index of Medical Specialties.
For those convinced cough medicines work, there’s a huge variety to choose from. Over-the-counter cough products include decongestants, expectorants, antihistamines, and antitussives (cough suppressants) to suppress cough, that may be “wet” when you need to expel extra mucous (phlegm) produced in the airways and lungs because of infection, or a dry cough that occurs when no extra mucus is produced.
Most cough medicines contain an antitussive, such as dextromethorphan, that suppresses coughing by blocking the body’s cough reflex. It may be combined with other ingredients, such as expectorants thin mucous to make it easier to cough it out; decongestants to open airways by narrowing blood vessels; and antihistamines (anti-allergy medicines) to reduce swelling in the nose and throat that restricts breathing.
Do cough syrups help?
There is no evidence that over-the-counter cough and cold medicines – both expectorants that promote expulsion of bronchial secretions and suppressants that prevent coughing -- suppress or stop coughing better than a placebo.
According to the British National Formulary, “the drawback of administering cough suppressants is rarely outweighed by the benefits... in fact, cough suppressants can cause sputum retention which is harmful in patients of chronic bronchitis and bronchiectasis. Opioid cough suppressants such as codeine are seldom sufficiently potent to be effective in severe cough.”
Cough suppressants contain soothing substances such as syrup or glycerol to relieve symptoms of a dry, irritating cough, but their use rarely outweigh the benefits. “Cough suppressants cause sputum retention, which harms people with chronic bronchitis and bronchiectasis,” says Dr Guhlati. At best, suppressants make you drowsy and help you sleep better.
Can cough remedies hurt?
Non-prescription cough and cold medicines contain multiple ingredients that can lead to accidental overdosing when more than one product containing the same active ingredient is used and must never be given to children under 4 years.
Codeine, a morphine derivative, is the most dangerous ingredient in many cough remedies. The US Food and Drug Administration has warned of deaths in children given codeine. In the UK, medicines with codeine are banned for use in children less than 18 years.
Codeine gets rapidly converted to morphine in the body, with conversion being accelerated in people with the CYP2D6 gene. This can lead to respiratory depression and death, which has resulted in its being banned for use in children below the age of 12 years and among breast-feeding women in several developed countries such as US, Britain, Canada, EU, Australia and New Zealand.
Since morphine is excreted in breast milk, the USFDA advisory warns against giving codeine-containing products must not be given to nursing mothers who are ultra-rapid metabolisers of codeine. Signs of morphine toxicity in babies include drowsiness, breathing difficulties and difficulty feeding.
Home remedies work best to relieve cold and cough symptoms. Steam inhalation helps clear airway and chest of excess mucous, while using a cool mist humidifier or taking a steamy shower helps nasal passages shrink to make breathing easier. Do not use warm mist humidifiers as they cause nasal passages to swell and restrict difficult.
Saline nose drops and sprays help keep nasal passages moist and make your nose feel less stuffy. Sucking on cough drops or just a hard candy relives a dry cough, as does adding lemon or honey in hot water or tea. That apart, all you need to do is drink plenty of liquids to stay hydrated and use paracetamol or ibuprofen to reduce fever, aches and pains.
A cough that persists for two weeks or more could be a symptom on an underlying disease, such as tuberculosis or chronic bronchitis, so you must get the disorder diagnosed and treated.