by Dr. Iain Corness
Want to stop that cough?
There has been a spate of upper
respiratory tract infections recently. More commonly known by the acronym
URTI - and we doctors, as you know, love acronyms! These infections tend to
come with any change of season, and we have just gone from cold to hot, in a
matter of just a few days! And there’s another wet one waiting round the
The URTI’s are well known for the coughing spasms that come with them. That
can range from the nagging irritating cough in the back of the throat right
the way through to the full-blown wracking cough that practically turns your
lungs inside out! Would you believe that the air velocity during coughing
can reach 800 km/h, or 500 mph in the old money!
So what can you take for that cough? The first thing you should be aware of,
is that coughing is a “natural” defense mechanism to clear the airways, but
if it becomes excessive it can cause fatigue and actually impair body
function and repair.
The cough reflex is generally initiated in one of two ways. The first is by
increased sputum (the yukky stuff you cough up) irritating the bronchial
passages. The other way is an increased sensitivity of the breathing tubes
to “normal” stimuli.
The sputum is brought up from the deep, dark recesses of the lungs by minute
“hair-like” projections in the breathing tubes called “cilia”. This is one
reason why smokers have a chronic cough, because the cilia are poisoned by
the nicotine laden smoke and cannot effectively bring out the tarry muck
from the base of the lungs, where it stays and later becomes lung cancer if
Lady Luck wasn’t smiling on you!
There is, however, a third type of recurrent cough not associated with URTI
and that is the cough produced as a side effect of medication called ACE
inhibitors, not to be confused with the above types.
But back to cough mixtures. The first group is called “Antitussives”. These
are designed to suppress the non-productive cough. This can be done one of
two ways - either numb the larynx and pharynx, or depress the cough center
in the brain, and you thought that cough mixtures weren’t dangerous because
you can buy them Over The Counter (OTC - another acronym!).
Local anesthesia is not used much, other than for the intractable cough in
cancer patients, and care has to be taken to avoid interruption of the
swallowing reflex, which if stopped completely can lead to food going down
into the lungs and pneumonia results.
The compounds that will act centrally include Codeine, Dihydrocodeine,
Hydrocodeine, Dextromethorphan and Pholcodine. They will all work to a
certain degree, but the least dangerous is Pholcodine with very little side
effects other than some slight sedation with some people, but ones with
codeine can cause constipation - a rare condition in Thailand if you eat
The second group is called “Expectorants or Mucolytics”. These are supposed
to work by making the yukky, sticky mucous more liquid. This in turn makes
it easier for the little cilia to transport the mucous. The compounds used
for this include Ammonium chloride, Potassium iodide, Ipecacuanha, Squill,
Eucalyptol and Guiaphenesin. Unfortunately, there is very little clinical
evidence that any of these compounds actually work very well, but the
pharmacist will love you!
Some centers have tried a third group, known as Bronchodilators. These are
generally aerosols designed to be used by asthmatics. They work well, IF
your cough is caused by asthma - otherwise, forget it! There is one
exception to this rule - Ipratropium aerosol can help chronic persistent
cough caused by Upper Respiratory Tract Infections (URTI) and chronic
So in conclusion, if you have an irritative dry cough try some Linctus
Pholcodine. With an URTI try some Ipratropium, but I would recommend you
talk to your doctor first!
So when should you grab some antibiotics for that cough? As a rough guide,
if the sputum is purulent, that is green or yellow, then you ‘may’ need
antibiotics. However, if your infection is viral, antibiotics do nothing
other than help breed antibiotic resistant bugs.
The message here is leave prescribing to your doctor, self-medicating can be
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