Cough

Coughing is a protective reflex action caused when the airway is being
irritated or obstructed. Its purpose is to clear the airway so that
breathing can continue normally. The majority of coughs presenting
in the pharmacy will be caused by a viral URTI. They will often
be associated with other symptoms of a cold. The evidence to support
the use of cough suppressants and expectorants is not strong but some
patients report finding them helpful.
What you need to know
Age (approximate)
Baby, child, adult
Duration
Nature
Dry or productive
Associated symptoms
Cold, sore throat, fever
Sputum production
Chest pain
Shortness of breath
Wheeze
Previous history
Chronic bronchitis
Asthma
Diabetes
Heart disease
Gastro-oesophageal reflux
Smoking habit
Present medication
Significance of questions and answers
Age
Establishing who the patient is – child or adult – will influence the
choice of treatment and whether referral is necessary.
COUGH 29
Duration
Most coughs are self-limiting and will be better within a few days with
or without treatment. In general, a cough of longer than 2 weeks’
duration that is not improving should be referred to the doctor for
further investigation.
Patients are often concerned when a cough has lasted for, what
seems to them to be, a long time. They may be worried that because
the cough has not resolved, it may have a serious cause.
Nature of cough
Unproductive (dry, tickly or tight)
In an unproductive cough no sputum is produced. These coughs are
usually caused by viral infection and are self-limiting.
Productive (chesty or loose)
Sputum is normally produced. It is an oversecretion of sputum that
leads to coughing. Oversecretion may be caused by irritation of the
airways due to infection, allergy, etc. or when the cilia are not working
properly (e.g. in smokers). Non-coloured (clear or whitish) sputum is
uninfected and known as mucoid.
Coloured sputum may sometimes indicate a bacterial chest infection
such as bronchitis or pneumonia and require referral. In these
situations the sputum is described as green, yellow or rust-coloured
thick mucus and the patient is more unwell usually with a raised
temperature, shivers and sweats. Sometimes blood may be present in
the sputum (haemoptysis), with a colour ranging from pink to deep
red. Blood may be an indication of a relatively minor problem such as
a burst capillary following a bout of violent coughing during an acute
infection, but may be a warning of more serious problems. Haemoptysis
is an indication for referral.
Antibacterials/antibiotics are not usually indicated for previously
healthy people with acute bronchitis. Most cases of acute bronchitis
are caused by viral infections, so antibacterials will not help. Two
systematic reviews of antibacterials for acute bronchitis found only
slight benefit, possibly reducing the duration of illness by about half a
day. Some people who have a tendency towards asthma develop a
wheezy bronchitis with a respiratory viral infection. They may benefit
from inhalation treatment used in asthma.
If a person has had repeated episodes of bronchitis over the years
they might have chronic bronchitis (defined as a chronic cough and/or
mucus production for at least 3 months in at least 2 consecutive years
when other causes of chronic cough have been excluded). So careful
questioning is important to determine this.
30 RESPIRATORY PROBLEMS
There is general consensus that antibacterials should be considered
if the person is elderly, has reduced resistance to infection, has
co-morbidity (such as diabetes or heart failure) or is deteriorating
clinically.
In heart failure and mitral stenosis the sputum is sometimes described
as pink and frothy or can be bright red. Confirming symptoms would
be breathlessness (especially in bed during the night) and swollen
ankles.
Tuberculosis (TB)
Until recently thought of as a disease of the past, the number of TB
cases has been rising in the UK and there is increasing concern about
resistant strains. Chronic cough with haemoptysis associated with
chronic fever and night sweats are classical symptoms. TB is largely
a disease of poverty and more likely to present in disadvantaged
communities. In the UK most cases of respiratory TB are seen in ethnic
minority groups, especially Indian and Africans. Human immunodeficiency
virus (HIV) infection is a significant risk factor for the development
of respiratory TB.
Croup (acute laryngotracheitis)
Croup usually occurs in infants. The cough has a harsh barking
quality. It develops 1 day or so after the onset of coldlike symptoms.
It is often associated with difficulty in breathing and an inspiratory
stridor (noise in throat on breathing in). Referral is necessary.
Whooping cough (pertussis)
Whooping cough starts with catarrhal symptoms. The characteristic
whoop is not present in the early stages of infection. The whoop is the
sound produced when breathing in after a paroxysm of coughing.
The bouts of coughing prevent normal breathing and the whoop
represents the desperate attempt to get a breath. Referral is necessary.
Associated symptoms
Cold, sore throat and catarrh may be associated with a cough. Often
there may be a temperature and generalised muscular aches present.
This would be in keeping with a viral infection and be self-limiting.
Chest pain, shortness of breath or wheezing are all indications for
referral (see p. 59).
Postnasal drip
Postnasal drip is a common cause of coughing and may be due to
sinusitis (see p. 199).
COUGH 31
Previous history
Certain cough remedies are best avoided in diabetics and anyone with
heart disease or hypertension (see pp. 36–7).
Chronic bronchitis
Questioning may reveal a history of chronic bronchitis, which is being
treated by the doctor with antibiotics. In this situation further treatment
may be possible with an appropriate cough medicine.
Asthma
A recurrent night-time cough can indicate asthma, especially in
children, and should be referred. Asthma may sometimes present as
a chronic cough without wheezing. A family history of eczema, hay
fever and asthma is worth asking about. Patients with such a family
history appear to be more prone to extended episodes of coughing
following a simple URTI.
Cardiovascular
Coughing can be a symptom of heart failure (see p. 60). If there is
a history of heart disease, especially with a persisting cough, then
referral is advisable.
Gastro-oesophageal
Gastro-oesophageal reflux can cause coughing. Sometimes such reflux
is asymptomatic apart from coughing. Some patients are aware of acid
coming up into their throat at night when they are in bed.
Smoking habit (see also ‘Smoking cessation’)
Smoking will exacerbate a cough and can cause coughing since it is
irritating to the lungs. One in three long-term smokers develop a
chronic cough. If coughing is recurrent and persistent, the pharmacist
is in a good position to offer health education advice about the
benefits of stopping smoking, suggesting NRT where appropriate.
However, on stopping, the cough may initially become worse as the
cleaning action of the cilia is re-established during the first few days
and it is worth mentioning this. Smokers may assume their cough is
harmless, and it is always important to ask about any change in the
nature of the cough that might suggest a serious cause.
Present medication
It is always essential to establish which medicines are currently being
taken. This includes those prescribed by a doctor and any bought
OTC, borrowed from a friend or neighbour or rediscovered in the
32 RESPIRATORY PROBLEMS
family medicine chest. It is important to remember the possibility of
interactions with cough medicine.
It is also useful to know which cough medicines have been
tried already. The pharmacist may decide that an inappropriate
preparation has been taken, e.g. a cough suppressant for a productive
cough. If one or more appropriate remedies have been tried
for an appropriate length of time without success, then referral is
advisable.
Angiotensin-converting enzyme (ACE) inhibitors
Chronic coughing may occur in patients, particularly women,
taking ACE inhibitors such as enalapril, captopril, lisinopril and
ramipril. Patients may develop the cough within days of starting
treatment or after a period of a few weeks or even months. The
exact incidence of the reaction is not known and estimates vary
from 2% to 10% of patients taking ACE inhibitors. ACE inhibitors
control the breakdown of bradykinin and other kinins in the
lungs, which can trigger a cough. Typically the cough is irritating,
non-productive and persistent. Any ACE inhibitor may induce
coughing and there seems to be little advantage to be gained
in changing from one to another. The cough may resolve or may
persist; in some patients the cough is so troublesome and distressing
that ACE inhibitor therapy may have to be discontinued. Any patients
in whom medication is suspected as the cause of a cough should be
referred to their doctor. Angiotensin 2 receptor antagonists, which
have similar properties to ACE inhibitors and which do not affect
bradykinin, can be used as an alternative preparation if cough is
a problem.
When to refer
Cough lasting 2 weeks or more and not improving
Sputum (yellow, green, rusty or blood-stained) (for further details, see p. 61)
Chest pain
Shortness of breath
Wheezing
Whooping cough or croup
Recurrent nocturnal cough
Suspected adverse drug reaction
Failed medication
After a series of questions the pharmacist should be in a position to
decide whether treatment or referral is the best option.
COUGH 33
Treatment timescale
Depending on the length of time the patient has had the cough and
once the pharmacist has recommended an appropriate treatment,
patients should see their doctor 2 weeks after the cough started if it
has not improved.
Management
Pharmacists are well aware of the debate about the clinical efficacy of
the cough remedies available OTC. In particular, the lack of scientific
evidence that expectorants have any effect and the use of combinations
with apparently contradictory ingredients have been cited.
However, many people who visit the pharmacy for advice do so
because they want some relief from their symptoms and, while the
effectiveness of cough remedies remains unproven, they can have a
useful placebo effect.
The choice of treatment depends on the type of cough. Suppressants
(e.g. pholcodine) are used to treat unproductive coughs, while expectorants
such as guaifenesin (guaiphenesin) are used in the treatment of
productive coughs. The pharmacist should check that the preparation
contains an appropriate dose, since some products contain subtherapeutic
amounts. Demulcents like Simple Linctus that soothe the throat
are particularly useful in children and pregnant women as they contain
no active ingredients.
The BNF gives the following guidance.
Expectorants: A simple expectorant mixture may serve a useful
placebo function and is inexpensive.
Suppressants: Where there is no identifiable cause (underlying disorder),
cough suppressants may be useful; e.g. if sleep is disturbed.
Demulcents: Preparations such as simple linctus have the advantage
of being harmless and inexpensive. Paediatric simple linctus is particularly
useful in children, and sugar-free versions are available.
Productive coughs should not be treated with cough suppressants
because the result is pooling and retention of mucus in the lungs and a
higher chance of infection, especially in chronic bronchitis.
There is no logic in using expectorants (which promote coughing)
and suppressants (which reduce coughing) together as they have opposing
effects. Therefore, products that contain both are not therapeutically
sound.
Cough suppressants
Controlled trials have not confirmed any significant effect of cough
suppressants over placebo in symptom reduction.
34 RESPIRATORY PROBLEMS
Codeine/pholcodine
Pholcodine has several advantages over codeine in that it produces
fewer side-effects (even at OTC doses codeine can cause constipation
and, at high doses, respiratory depression) and pholcodine is less liable
to be abused. For these reasons, codeine is best avoided in the treatment
of children’s coughs and should never be used in children under
1 year. Both pholcodine and codeine can induce drowsiness, although
in practice this does not appear to be a problem. Nevertheless, it is
sensible to give an appropriate warning. Codeine is well known as a
drug of abuse and many pharmacists choose not to recommend it.
Sales often have to be refused because of knowledge or likelihood of
abuse. Pholcodine can be given at a dose of 5 mg to children over
2 years of age (5 mg of pholcodine is contained in 5 ml of pholcodine
linctus BP). Adults may take doses of up to 15 mg three or four times
daily. The drug has a long half-life and may be more appropriately
given as a twice-daily dose.
Dextromethorphan
Dextromethorphan is less potent than pholcodine and codeine. It is
generally non-sedating and has few side-effects. Occasionally, drowsiness
had been reported but, as for pholcodine, this does not seem to be
a problem in practice. Dextromethorphan can be given to children
of 2 years and over. Dextromethorphan was generally thought to have
a low potential for abuse. However, there have been rare reports of
mania following abuse and consumption of very large quantities,
and pharmacists should be aware of this possibility if regular purchases
are made.
Demulcents
Preparations such as glycerin, lemon and honey or Simple Linctus are
popular remedies and are useful for their soothing effect. They do not
contain any active ingredient and are considered to be safe in children
and pregnant women. Their pleasant taste makes them particularly
suitable for children but their high syrup content should be noted.
Expectorants
Two mechanisms have been proposed for expectorants. They may act
directly by stimulating bronchial mucus secretion, leading to increased
liquefying of sputum, making it easier to cough up. Alternatively, they
may act indirectly via irritation of the gastrointestinal (GI) tract,
which has a subsequent action on the respiratory system resulting
in increased mucus secretion. This latter theory has less convincing
evidence than the former to support it.
COUGH 35
Guaifenesin (guaiphenesin)
Guaifenesin is commonly found in cough remedies. In adults, the dose
required to produce expectoration is 100–200 mg, so in order to have
a theoretical chance of effectiveness, any product recommended
should contain a sufficiently high dose. Some OTC preparations contain
subtherapeutic doses. In the USA, the Food and Drugs Administration
(FDA, the licensing body) reviewed OTC medicines, and
evidence from studies supporting guaifenesin was sufficiently strong
for the FDA to be convinced of its efficacy.
Cough remedies: other constituents
Antihistamines
Examples used in OTC products include diphenhydramine and
promethazine. Theoretically these reduce the frequency of coughing
and have a drying effect on secretions, but in practice they also induce
drowsiness. Combinations of antihistamines with expectorants are
illogical and best avoided. A combination of an antihistamine and a
cough suppressant may be useful in that antihistamines can help to dry
up secretions and, when the combination is given as a night-time dose
if the cough is disturbing sleep, a good night’s sleep will invariably
follow. This is one of the rare occasions when a side-effect proves
useful. The non-sedating antihistamines are less effective in symptomatic
treatment of coughs and colds because of their less pronounced
anticholinergic actions.
Interactions. Traditional antihistamines should not be used by patients
who are taking phenothiazines and tricyclic antidepressants because
of additive anticholinergic and sedative effects. Increased sedation will
also occur with any drug that has a CNS depressant effect. Alcohol
should be avoided because this will also lead to increased drowsiness.
See p. 23–4 for more details of interactions, side-effects and contraindications
of antihistamines.
Sympathomimetics
Pseudoephedrine is the most commonly used oral decongestant included
in cough and cold remedies (see also p. 21) for its bronchodilatory
and decongestant actions. It has a stimulant effect that may lead
to a sleepless night if taken close to bedtime. It may be useful if the
patient has a blocked nose as well as a cough and an expectorant/
decongestant combination can be useful in productive coughs. Sympathomimetics
can cause raised blood pressure, stimulation of the
heart and alterations in diabetic control. Oral sympathomimetics
should be used with caution in patients with
36 RESPIRATORY PROBLEMS
diabetes
coronary heart disease (e.g. angina)
hypertension
hyperthyroidism
Interactions. Sympathomimetics should be avoided by patients taking
monoamine oxidase inhibitors (e.g. phenelzine)
reversible inhibitors of monoamine oxidase A (e.g. moclobemide)
beta-blockers
tricylic antidepressants (e.g. amitriptyline); a theoretical interaction
which does not seem to cause problems in practice.
Theophylline
Theophylline is sometimes included in cough remedies for its bronchodilator
effect. OTC medicines containing theophylline should
not be taken at the same time as prescribed theophylline since
toxic blood levels and side-effects may occur. The action of theophylline
can be potentiated by some drugs, e.g. cimetidine and
erythromycin.
Levels of theophylline in the blood are reduced by smoking and
drugs such as carbamazepine, phenytoin and rifampicin that induce
liver enzymes, so that the metabolism of theophylline is increased and
lower serum levels result.
Side-effects include GI irritation, nausea, palpitations, insomnia and
headaches. The adult dose is typically 120 mg three or four times daily.
It is not recommended in children. Before selling any OTC product
containing theophylline, check that the patient is not already taking
the drug on prescription.
Practical points
Diabeties
In short-term acute conditions the amount of sugar in cough medicines
is relatively unimportant. Diabetic control is often upset during infections
and the additional sugar is not now considered to be a major
problem. Nevertheless, many diabetic patients may prefer a sugar-free
product, as will many other customers who wish to reduce sugar
intake for themselves and their children, and many such products
are now available. As part of their contribution to improving dental
health, pharmacists can ensure that they stock and display a range of
sugar-free medicines.
Steam inhalations
These can be useful, particularly in productive coughs. Some clinical
trials indicate benefit and none have found any harm. The steam helps
COUGH 37
to liquefy lung secretions and patients find the warm moist air comforting.
While there is no evidence that the addition of medications to
the water produces a better clinical effect than steam alone, some may
prefer to add a preparation such as menthol and eucalyptus or a
proprietary inhalant. One teaspoonful of inhalant should be added
to a pint of hot (not boiling) water and the steam inhaled. Apart from
the risk of scalding, boiling water volatilises the constituents too
quickly. A cloth or towel can be put over the head to trap the steam.
Fluid intake
Maintaining a high fluid intake helps to hydrate the lungs and
hot drinks can have a soothing effect. General advice to patients
with coughs and colds should be to increase fluid intake by around
2 L a day.
Coughs in practice
Case 1
Mrs Patel, a woman in her early twenties, asks what you can recommend
for her son’s cough. On questioning you find out that her
son, Dillip, aged 4, has had a cough on and off for a few weeks. He
gets it at night and it is disturbing his sleep although he doesn’t seem
to be troubled during the day. She took Dillip to the doctor about
3 weeks ago, and the doctor explained that antibiotics were not
needed and that the cough would get better by itself. The cough is
not productive and she has given Dillip some Tixylix before he goes
to bed but the cough is no better. Dillip is not taking any other
medicines. He has no pain on breathing or shortness of breath. He
has had a cold recently.
The pharmacist’s view
This is a 4-year-old child who has a night-time cough of several weeks’
duration. The doctor’s advice was appropriate at the time Dillip saw
him. However, referral to the doctor would be advisable because the
cough is only present during the night. A recurrent cough in a child
at night can be a symptom of asthma, even if wheezing is not present.
It is possible that the cough is occurring as a result of bronchial
irritation following his recent viral URTI. Such a cough can last for
up to 6 weeks and is more likely to occur in those who have asthma or
a family history of atopy (a predisposition to sensitivity to certain
common allergens such as house dust mite, animal dander and pollen).
Nevertheless, the cough has been present for several weeks without
improvement and medical advice is needed.
38 RESPIRATORY PROBLEMS
The doctor’s view
Asthma is an obvious possibility. It would be interesting to know if
anyone else in the family suffers from asthma, hay fever or eczema and
whether Dillip has ever had hay fever or eczema. Any of these features
would make the diagnosis more likely. Mild asthma may present in
this way without the usual symptoms of shortness of breath and
wheezing.
An alternative diagnosis could still include a viral URTI. Most
coughs are more troublesome and certainly more obvious during the
night. This can falsely give the impression that the cough is only
nocturnal. It should also be remembered that both diagnoses could
be correct, as a viral infection often initiates an asthmatic reaction.
Because the diagnosis is uncertain and inhaled oral steroids may be
appropriate, referral to the doctor is advisable.
If, after further history-taking and examination, the doctor feels
that asthma is a possibility, then treatment would be based on the
British Thoracic Society guidelines, which are summarised in the BNF.
Naturally this would only be carried out after full discussion and
agreement with the parents. Many parents are loath to have their
child labelled as an asthma sufferer. The next problem is to prescribe
a suitable inhalation device for a 4-year-old child. This may be an
inhaler with a spacer device or a breath-actuated inhaler or a drypowder
inhaler. It would be usual to try a twice-daily dosage for 2–3
weeks and then review for future management.
The parent’s view
‘I was hoping the pharmacist could recommend something but she
seemed to think Dillip should see the doctor. She didn’t really explain
why though.’
Case 2
A man aged about 25 asks if you can recommend something for his
cough. He sounds as if he has a bad cold and looks a bit pale. You find
out that he has had the cough for a few days, with a blocked nose and
a sore throat. He has no pain on breathing or shortness of breath. The
cough was chesty to begin with but he tells you it is now tickly and
irritating. He has not tried any medicines and is not taking any
medicines from the doctor.
The pharmacist’s view
This patient has the symptoms of the common cold and none of
the danger signs associated with a cough that would make referral
necessary. He is not taking any medicines, so the choice of possible
COUGH 39
treatments is wide. You could recommend something to treat his
congested nose as well as his cough, e.g. a cough suppressant and a
sympathomimetic. Simple Linctus and a systemic or topical decongestant
would also be a possible option. If a topical decongestant were
to be recommended, he should be warned to use it for no longer than
1 week to avoid the possibility of rebound congestion.
The doctor’s view
The action suggested by the pharmacist is very reasonable. It may be
worthwhile explaining that he is suffering from a viral infection that is
self-limiting and should be better within a few days. If he is a smoker it
would be an ideal time to encourage him to stop.