Dry or Chesty Cough: What to Take for Each

Before choosing a syrup, ask yourself one question: does this cough bring anything up? If mucus comes up with each cough, you have a productive cough and a cough suppressant is contraindicated, not simply discouraged. If the cough is dry and tickly, the kind that scratches and produces nothing, then a cough suppressant makes sense for a few days. It is the only fork in the road that matters, and almost nobody takes it at the pharmacy shelf.

First, how long have you been coughing?

Duration changes the approach more than the type of cough. The usual classification is simple:

• Acute cough: under 3 weeks. It usually starts suddenly and almost always comes from a cold, flu or sinusitis. It clears up on its own.
• Subacute cough: 3 to 8 weeks.
• Chronic cough: over 8 weeks. At this point self-medicating is no longer the answer; finding the cause is.

Pharmacy syrups are designed for the first category and for short courses. When a cough drags on, the problem is rarely solved by the product that silences it.

Dry cough: what a cough suppressant does

Dextromethorphan is the most widely used over-the-counter cough suppressant in Spain. It acts centrally: it dampens the cough centre in the brainstem and raises the threshold at which the reflex is triggered. Its product information indicates it for the symptomatic treatment of unproductive cough (irritative, nervous) in adults and adolescents aged 12 and over. The effect starts after 15 to 30 minutes and lasts about 6 hours.

The interesting part is the list of contraindications, because it describes exactly who should not take it: productive cough, asthmatic cough, COPD, respiratory failure or pneumonia. The logic is the same in every case: if you have secretions to clear or your airway is already compromised, switching off the reflex that expels them makes things worse.

Two warnings worth keeping in mind:

• Serious psychiatric interactions. It is contraindicated with MAOIs, SSRIs, bupropion, linezolid, procarbazine or selegiline, or if you have taken any of them in the previous two weeks, because of the risk of serotonin syndrome. If you take an antidepressant, ask before buying any cough syrup.
• No alcohol, grapefruit or bitter orange during treatment: both juices inhibit the enzymes that break it down and raise its levels in the blood.

And a clear time limit: if the cough gets worse, lasts more than 7 days or comes with a high fever, a rash or a persistent headache, stop relying on the syrup and get advice.

Codeine is a separate case. Since 2015 the AEMPS, Spain’s medicines agency, has restricted its use as a cough suppressant: it must not be used in children under 12, in CYP2D6 ultra-rapid metabolisers, or while breastfeeding.

Chesty cough: mucolytics and expectorants

Here the goal is the opposite: to help the mucus come up more easily, not to make the cough disappear. Acetylcysteine, the most common mucolytic, breaks the disulphide bridges in mucoproteins, lowers the viscosity of secretions and makes it easier for the cilia lining the airways to move them. Its authorised indication is respiratory conditions associated with thick, sticky mucus hypersecretion in adults, with a typical dose of one 600 mg effervescent tablet a day.

Three practical details that are often overlooked:

• It is not forever. It should not be taken for more than 14 days without medical advice, and if you are not better, or are worse, after 4 to 5 days, get advice.
• Never in children under 2. Mucolytics can block babies’ airways, because their ability to cough up mucus is limited.
• Keep oral antibiotics at least 2 hours apart. And if you have asthma, be careful: it can cause bronchospasm, in which case it must be stopped immediately.

On ambroxol and bromhexine, two other best-selling expectorants: after a European review, the EMA concluded that the risk of severe allergic reactions is small but real, and includes anaphylactic reactions and severe skin reactions such as erythema multiforme or Stevens-Johnson syndrome. Their product information was updated to warn that treatment must be stopped immediately if lesions appear on the skin or mucous membranes.

The table that settles it

	Dry / tickly cough	Productive / chesty cough
What it does	Suppresses the cough reflex	Thins mucus so it can be cleared
Typical example	Dextromethorphan	Acetylcysteine, ambroxol, guaifenesin
Usual minimum age	12 years (depending on product)	2 years
Use without advice	7 days at most	No better after 4 to 5 days → get advice
Contraindicated if	Mucus, asthma, COPD, pneumonia	Under 2 years old
Never together with	Mucolytics, MAOIs/SSRIs, alcohol	Cough suppressants

The most common mistake: taking both at once

It seems reasonable (one loosens the mucus, the other calms the cough) and it is exactly what both sets of product information explicitly advise against. The one for dextromethorphan warns that, combined with expectorants or mucolytics, suppressing the cough reflex can lead to lung obstruction by increasing the volume and fluidity of bronchial secretions. The one for acetylcysteine says it from the other side: together with a cough suppressant it can cause dangerous secretion build-up.

In plain terms: you have made the mucus more plentiful and more liquid, and at the same time switched off the mechanism that clears it. It stays inside.

A related point: in older or frail people, whose cough reflex is already weaker, the product information recommends taking the mucolytic in the morning, so there is the whole day ahead to cough the mucus up.

What helps in both cases

Simple measures are still the best value, especially since an acute cough will clear up on its own anyway:

• Plenty of fluids. They thin the mucus in the throat and make it easier to cough up.
• Humidity. A vaporiser or a steamy shower soothes a dry throat. If you use a humidifier, clean it well.
• Lozenges or pastilles for a dry, tickly cough. Never in children under 3, because of the choking risk.
• Honey, for children over one year. Systematic reviews of acute cough in children found that honey reduces how often children cough compared with no treatment, and is not significantly different from dextromethorphan. Under one year it is not allowed, because of the risk of infant botulism.
• Don’t smoke, and avoid other people’s smoke, the irritant that most prolongs a cough.

With children, caution is high in general: it is best to get advice before giving over-the-counter cough suppressants to children under 6, even those labelled for children, because they probably won’t work and can have serious side effects.

When the culprit is a medicine you already take

A persistent dry cough that appeared weeks or months after starting treatment for blood pressure deserves a review: ACE inhibitors (and, less often, angiotensin receptor blockers) cause cough as a known side effect. No syrup will get rid of it while you keep taking the medicine. The solution is to talk to whoever prescribed it, not to add another product.

When to see a doctor

Call 112 if you have:

• Difficulty breathing or a feeling of choking.
• Hives or swelling of the face or throat with difficulty swallowing.
• A high-pitched, harsh sound when breathing in (stridor).

See your doctor as soon as possible if you have a cough and also:

• You are coughing up blood.
• Fever, or thick, foul-smelling, greenish-yellow phlegm.
• Unintentional weight loss and night sweats.
• Heart disease, swollen legs or a cough that gets worse when you lie down.
• You have been in contact with someone with tuberculosis.
• The cough lasts more than 10 to 14 days, or goes beyond 3 weeks without improving.
• A baby under 3 months old with a cough.
• A violent cough that starts suddenly.
• You have asthma or COPD and your cough has changed pattern.
• Lesions appear on your skin or mucous membranes while taking a mucolytic.

This article is for information only and does not replace an individual assessment by a doctor or pharmacist. Sources: AEMPS/CIMA: Summary of product characteristics, cinfatós antitusivo 15 mg (dextromethorphan), AEMPS/CIMA: Summary of product characteristics, Acetilcisteína Aurovitas 600 mg effervescent tablets, AEMPS: Codeine, new restrictions on use as a cough suppressant in children (2015), EMA: Article 31 referral on ambroxol and bromhexine, NIH MedlinePlus: Cough, Cochrane / PubMed: Honey for acute cough in children.