Drugs Used for Cough

Cough is the physiological response to a foreign object in the throat. This response can also be pathologic when certain pathological organisms are involved. Cough is an important topic for all young doctors who will soon start their internships in an emergency or OPD-based style. Cough is one of the most basic complaints of a patient arriving at the emergency department. 

Thus, cough becomes important not only for competitive exams but also when dealing with patients on a day-to-day basis. Let us read about this in detail, starting with the classification.

Classification of Cough

Cough for easy diagnosis is divided into two groups, which have specific symptoms we need to know to make an effective treatment plan.

1. Dry cough—This type of cough produces no sputum. It is very uncomfortable and must be suppressed. The person will experience a dry cough with little to no radiographical changes in the chest.
2. Productive cough—This type of cough produces sputum. The sputum must be let out, as it can lead to further problems, like chest congestion.

In this blog, we will discuss the treatment of dry and productive coughs. This chapter of pharmacology can be read in depth by signing up for the PrepLadder NEET PG course.

Drugs for Dry Cough

• Opioids: Opioids are used to suppress dry cough. These opioids are:
  • Codeine
  • Pholcodine
  • Levopropoxyphene

There are many side effects associated with the use of opioids. The adverse effects of opioids are:

• Sedation
• Constipation
• Possible abuse
• Higher doses can cause respiratory depression and thus aren’t used in the pediatric population.
• NMDA Antagonist: NMDA Antagonists are also used to suppress dry cough. One such drug used is Dextromethorphan. This drug has No or fewer chances of sedation, abuse, and respiratory depression. Dextromethorphan can be used in children. The combination of codeine and dextromethorphan cannot be used and is considered irrational.
• Benzonatate: This can also be used to suppress dry cough. It is a local anesthetic. It has two actions:
  • Brain - Central mechanism to suppress cough.
  • Lung - Peripheral mechanism to inhibit peripheral Lung stretch receptors

Drugs for Productive Cough

The sputum must be removed, or the infection will flare up. The following classes of drugs can be used for a productive cough.

• Expectorants 
  • They increase the expulsion of sputum from the lungs. E.g., Guaiphenesin, Ammonium chloride.
• Mucolytics
  • They will convert the thick sputum into thin and watery sputum. E.g., Ambroxol, Bromhexine. 
  • These drugs depolymerize the mucopolysaccharide in the sputum.
• Carbocysteine & Acetylcysteine
  • They break the disulfide bond in the sputum to convert thick sputum into thin sputum.
  • Acetylcysteine is also the antidote for Paracetamol (PCT) toxicity.
• Cough syrups cannot be exchanged because if productive cough syrup is used for dry cough, it tries to expel the sputum by increasing the cough, which worsens the condition.

Frequently Asked Questions:

Q: What drugs are used to convert the thick sputum to thin and watery sputum?

Answer: Mucolytics like Ambroxol are used to convert the thick sputum to thin and watery sputum.

Q: What drugs are used for the expulsion of sputum from the lungs?

Answer: Expectorants like Guaiphenesin and ammonium chloride are used for the expulsion of sputum from the lungs.

Q: What is the use of Acetylcysteine?

Answer: Acetylcysteine is used to break the disulfide bond in the sputum to convert thick sputum into thin sputum. Acetylcysteine is also the antidote for Paracetamol (PCT) toxicity.

Q: Which opioids are used to suppress opioids?

Answer: Codeine, Pholcodine and Levopropoxyphene.

Q: What are the eye changes in opioid Poisening?

Answer: Pin point pupils.

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