Cough

Introduction

Cough is the most common respiratory symptom and is usually self-limiting (will resolve in 3-4 weeks without the need for antibiotics).

  • Coughing is the body's defence mechanism to clear the airways of foreign bodies and particulate matter.



Questions to Ask the Patient

Some important information to be gathered include

Duration of the cough
  • Duration longer than 2-3 weeks with no improvement or is getting worse suggests non-acute cause of cough and requires further investigation, such as tuberculosis.
Chest pain, haemoptysis (coughing up blood) or shortness of breath
  • Suggest possible sinister pathology or severe cases of simple viral infection, and requires further investigation.
Age
  • Children or adult? If children, how many years old?
Persistent nocturnal cough in children
  • Suggests possible asthma, especially those with family history.

Nature of cough

  • Coughs can be described as productive (chesty) or non-productive (dry, tight, tickly). However, many patients will say that they are not producing sputum, although they may go onto say that they 'can feel it on their chest'. In these cases, the cough is probably productive in nature and should be treated as such.
Smoking
  • Patients who smoke are more prone to chronic and recurrent cough. Over time, this might develop into chronic bronchitis and COPD.

NOTE: Post-nasal drip can sometimes cause a cough. “Post-nasal drip” is when mucus from your nose or sinuses drips down the back of your throat.



Medications

Depending on the nature of cough, the OTC medication differs.

  • Productive (chesty)
    • Expectorants, e.g. guaifenesin, ammonium chloride, ipecacuanha
    • Mucolytics, e.g. bromhexine, ambroxol (metabolite of bromhexine), acetylcysteine, carbocisteine, cyclidrol
  • Non-productive (dry, tight, tickly)
    • Cough suppressants (antitussives), e.g. pholcodine, dextromethorphan, cloperastine

Antihistamines have been included in cough remedies for decades.

  • Their mechanism of action is thought to be through the anticholinergic-like drying action on the mucous membranes and not via histamine.
  • Citric acid-induced cough studies have demonstrated significant antitussive activity compared with placebo, and results from chronic cough trials support an antitussive activity for diphenhydramine. However, trials that showed a significant reduction in cough frequency suffered from having small patient numbers, thus limiting their usefulness.
  • In practice, diphenhydramine also induces drowsiness.

NOTE: All active ingredients to treat cough were brought to the market many years ago when clinical trials suffered from flaws in study design compared with today's standard.



Paediatric

Due to growing evidence of the potential harm that cough and cold medications can pose to young children, either due to adverse effects or from accidental inappropriate dosing,

At Malaysia, we are still practicing giving cough and cold mixtures for patients aged above 2 years old.



Combination Products

Cough, cold, sore throat and rhinitis often coexist. Hence, many OTC cough preparations are combinations of agents. Some of these include ingredients, such as decongestants, that target other aspects of the common cold.

It should be noted that some combination products contain sub-therapeutic doses of the active ingredients, while a few contain illogical combinations such as cough suppressants with an expectorant, or an antihistamine with an expectorant. If possible, these should be avoided.



Herbal Products

A number of herbal ingredients are included in cough medicines; for example, Pelargonium sidoides (geranium), echinacea, Andrographis paniculata (green chiretta), ivy, primrose and thyme.

  • In Wagner’s review, very low-quality evidence was found that ivy, primrose or thyme significantly reduced cough compared with placebo in people with acute cough.



Medicine-induced Cough

A 50-year-old female customer walked into your pharmacy to have her usual medication filled; a box of Glucophage XR 750 mg and a bottle of Coversyl 5 mg. She was then complaining that she has been having a cough, with very little phlegm for quite some time. She is wondering on how long a cough usually last and what remedy that will really soothe her cough.

In the conversation,

  • You explained to the customer that cough is usually self-limiting in nature
  • You realized that the customer has been having the cough for 3 months and tried some remedies but all did not really work.

Well, this could be a typical case presentation of patient experiencing dry cough as a side effect of ACE inhibitor. Does it ring a bell now?

You decide to investigate further. The customer replied that the cough started after she started taking Coversyl 5 mg for high blood pressure. You explained to the customer on your concern and refer her back to her family doctor to review her blood pressure medication.

Remember, when you are practicing as pharmacist, NEVER FORGET what you have learned at university.

  • In examination, we know there is a problem existed in the question, so we try to be extra careful.
  • In real life, it is where we should be 200% more careful, because we never know where and when the problem is.



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