Anti-tussive agents. Drugs affecting bronchial secretions and Mucolytic agents

Question 1

Classification?

Answer 1

1. Drugs for the treatment of “DRY COUGH” :
   - Drugs with central action (causing dependence and not causing dependence)
   - Drugs with peripheral action.
2. Drugs used for the treatment of “PRODUCTIVE COUGH”
   - Expectorants (emoliants, liquescent expectorants, purgantive expectorants and bronchoantiseptics.)
   - Mucolytic agents
3. Combined anti-cough medications.

Question 2

Explain the pharmacokinetics of these drugs?

Answer 2

1. Anti tussive (Cause dependence, central effects) - good oral absorption with BBB and BPB distribution. Metabolism of the anti tussive drugs into morphine takes place.
2. Butamirate (Doesn’t cause dependency)- oral administration, high distribution and urinary excretion.
3. “Mucolytics” - can be administered orally, IM and IV too. Metabolism of the “BROMHEXINE” into “AMBROXOL” (active metabolite).

Question 3

Explain the pharmacodynamics of the centrally acting and peripherally acting cough treatments?

Answer 3

1. Anti tussives for dry coughs (cause dependence, central effects) function to :
   - Suppress coughing centre.
   - Reduce peripheral cough impulses.
   - Acts as “Opioid analgesic” (selective suppressor for the cough centre)
   - “Noscarpine” causes cough depression.
2. Butamirate (No dependence) = moderate bronchodilation, anti-inflammatory effects.
3. Drugs with peripheral action “PRENOXIDIAZINE” = peripheral cough depressant.

Question 4

Pharmacodynamics of the Expectorants to treat “Productive cough”.

Answer 4

1. Expectorants : Their main action is to act peripherally to increase mucus section and aid clearance of mucus from the respiratory tract. There are 4 types of the Expectorates.
2. Liquiscent expectorants use salts/substances to achieve its effects.
   - Iodine salts : Cause irritation of the bronchial mucosa secretory cells, causing a increased bronchial secretion.
   - Ammonium salts: Same effect as iodine salts, with gastric irritation.
   - Guaiphenesin: Increases the quantity of secretion in the trachea/bronchi and reduces its viscosity.
   - Hypertonic saline : Increased secretion volume, reduced viscosity.
   - Sodium Bicarbonate: Used as inhalation, addition of alkaline PH causes H+ bond breakage in secretion.
3. Emollient: Reduce respiratory mucosa irritability and reduce the cough reflex.
4. Purgantive: Facilitate expectoration via increased bronchial excretions, restoration of respiratory clearance mechanisms to stimulate expectoration.
5. Bronchoantiseptics: Secretolytic action, bronchodilator and anti-inflammatory effects.

Question 5

Explain pharmacodynamics of the Mucolytic drugs?

Answer 5

Increased volume and reduced viscosity of the sputum.

Question 6

Contraindications of the drugs?

Answer 6

1. Impaired thyroid function.
2. Contraindicated in infants, young children where bronchial muscles are lesser developed, can lead to issues with respiration such as worsening of the pulmonary ventilation.
3. “Liquescnet expectorate” the irritant action (Iodine salts) is not desirable if bronchial mucosa is acutely inflamed.

Question 7

Adverse effects of these drugs?

Answer 7

1. Drugs causing dependence (anti-tussive) effects are : Constipation and respiratory depression.
2. Drugs which dont cause dependence (Butamirate) = Skin rashes, GI symtpoms.
3. Mucolytics : Nausea and vomiting.