When Should Veterinarians Suppress Cough?

Cough suppression plays a specific role in managing respiratory diseases in dogs and cats. The aim is not to eliminate a protective reflex indiscriminately, but to reduce excessive coughing when it is no longer serving a useful purpose or contributing to airway irritation and patient distress^[1]. 

When Cough Becomes Part of the Problem 

Persistent nonproductive coughing can damage the airway mucosa and contribute to a cycle of airway irritation and further coughing^[1]. 

Antitussive therapy may therefore be considered when coughing is: 

• Nonproductive and persistent 
• Affecting quality of life 
• Disrupting sleep 
• Associated with syncope 
• Severe enough to cause significant distress 
• Continuing despite appropriate treatment of the underlying disease^[1],[2] 

This approach can be relevant in chronic airway conditions such as tracheal collapse and chronic bronchitis, as well as coughing associated with external airway compression^[1],[2]. 

The objective is to reduce the severity and frequency of excessive coughing while maintaining the airway's ability to clear material when that clearance is necessary. 

Productive Cough Requires Caution 

Not every persistent cough should be suppressed. 

A productive cough helps remove mucus and cellular debris from the respiratory tract. Suppressing this reflex can interfere with airway clearance, particularly when substantial respiratory secretions are present. 

This is why antitussives are generally contraindicated in bacterial pneumonia. Retention of mucus and debris can impair clearance of respiratory material^[3]. 

The underlying disease therefore remains central to the treatment decision. A frequent cough is not, by itself, an indication for an antitussive. 

Emergency Situations Can Be Different 

Severe coughing associated with airway obstruction can create an acute cycle of stress and respiratory compromise. In dogs with conditions such as laryngeal paralysis or tracheal collapse, cough suppression combined with sedation may be required when hypoxia, exhaustion, or severe distress develops^[1]. 

Sedation must be carefully monitored because a sedated animal with an unprotected airway can deteriorate or develop respiratory arrest. 

Selecting an Antitussive 

Opioids reduce responsiveness of the cough centre and can also decrease peripheral airway irritation^[1],[4]. 

Hydrocodone is commonly used in veterinary patients and is more potent and less sedating than codeine. Cophenotrope has also been reported to be fairly effective^[1],[4]. 

Dextromethorphan is generally not sedating but is considerably less effective than hydrocodone, with reported efficacy of 50–100% of codeine. Its effectiveness can be intermittent in dogs with chronic bronchitis and infectious tracheobronchitis. It is considered the safest antitussive for cats^[1]. 

Opioids can cause sedation, constipation, respiratory depression, excitement, and muscular spasms, with adverse effects particularly relevant in cats. Treatment should be titrated to the lowest effective dose and frequency^[1]. 

Break the Cycle Without Blocking Clearance 

For dogs and cats with excessive, nonproductive chronic cough, appropriate suppression can reduce airway irritation and improve comfort. But when coughing is helping clear respiratory secretions, suppressing it may interfere with an important protective mechanism. 

The clinical goal is therefore controlled cough, not simply less cough.

References:

1. Hsieh BM, Beets AK. Coughing in small animal patients. Frontiers in Veterinary Science. 2020 Jan 21;6:513. https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2019.00513/pdf
2. Martin M, Pereira YM. Approach to the coughing dog. In Practice. 2013 Oct;35(9):503-17. https://www.researchgate.net/profile/Mike-Martin-7/publication/275001097
3. Dear JD. Bacterial pneumonia in dogs and cats. The Veterinary Clinics of North America. Small Animal Practice. 2013 Nov 21;44(1):143. https://pmc.ncbi.nlm.nih.gov/articles/PMC7114586/pdf/main.pdf
4. Boothe DM. Drugs affecting the respiratory system. Veterinary Clinics of North America: Exotic Animal Practice. 2000 May 1;3(2):371-94. https://www.academia.edu/download/112717671/S1094-919428172930077-420240324-1-5ql4k3.pdf