Drugs used in cough

useful for UG MBBS students

1. DRUGS USED IN COUGH Dr.SUMITHA.A MBBS.,MD ASSISTANT PROFESSOR PHAMACOLOGY

2. Cough is a protective reflex. Due to stimulation of mechano or chemoreceptors in throat,respiratory passages Stretch receptors in lungs.

3. Mechanism of cough

4. Etiology of Cough • • • • The most common causes of cough Acute cough (<3 weeks): URTIs (especially the common cold, acute bacterial sinusitis, and pertussis), pneumonia, pulmonary embolus, and congestive heart failure. Sub-acute cough (3-8 weeks): post-infectious Chronic cough (>8 weeks): In a smoker: chronic obstructive lung disease or bronchogenic carcinoma. In a nonsmoker: postnasal drip ,GERD

5. Types of Cough • Non-productive (dry): No useful purpose, increases discomfort to the patient  needs suppression • Productive (tenacious): Presence of excessive sputum  suppression not desired  needs coughing/clearing out of the sputum

6. Pharyngeal demulcents • Sooth the throat and reduce afferent impulses from the inflamed/irritated pharyngeal mucosa. • E.g: Lozenges, cough drops, linctuses containing syrup, Glycerine, Liquorice

7. Antitussives (Cough center supressants ) • • • • • • • These act in CNS to raise the threshold of cough center peripherally in Respiratory tract to reduce tussal impulse Should be used only for dry unproductive cough E.g : Opioids: Codein, Pholcodein Non-opioids: Noscapine, Dextromethorpha n Antihistaminics: Chlorpheniramine, Diphenhydramine, Promethazine

8.  Semi synthetic opioid analgesic  Less potent than morphine  More selective for cough centre  Potent cough suppressant action at low dose :15 mgtablet ;15mg/5ml linctus Anti tussive action –blocked by Naloxone S/E  Constipation ,Drowsiness, Respiratory depression OPIOIDS Codeine

9. Pholcodeine  Antitussive efficacy similar to codeine  No analgesic/addictive effect  Longer acting  Dose 10-15mg .

10. NON- OPIOIDS Dextromethorphan D-isomer of methorphan  Raise threshold for cough centre M.O.A  NMDA receptor antagonist  Least addiction and constipation Ascoril –D: dextromethorphan,CPM,phenylephrine Uses Use along with antihistamine and bronchodilator as suppressant S/E Nausea, vomiting, ataxia Dose- 10mg TDS

11. Noscapine  Opium alkaloids belongs to benzyl isoquinoline group  No addictive, analgesic & constipating properties  Do not interfere with mucocilliary movement  Release histamine – produce bronchoconstiction in asthmatics. S/E  Nausea,headache,tremor Dose 15 mg -30 mg

12. PRENOXDIAZINE - desensitises pulmonary stretch receptors and reduces tussal impulses originating in the lungs. It has moderate antitussive action Orally 100-200mg TDS Anti histamines: Chlorpheniramine -2 to 5 mg,Promethazine 25 mg Sedative,anticholinergic property Peripherally acting antitussives

13. Bronchial secretion enhancers Ammonium chloride, Sodium citrate or potassium citrate , Guaiphenesin,vasaka and Tolu balsam stimulate the flow of respiratory tract secretions by stimulating the bronchial secretory cells (to increase the volume) and ciliary movements (to facilitate their removal) Expectorants

14. Sodium & potassium citrate M.O.A  Increase Bronchial secretion by salt action Guaifenesin  Expectorant drug M.O.A  Increase airway secretion and mucocilliary activity  Dose 100-200mg BD Ammonium chloride,Ipecac  Reflexly increase respiratory secretion  Gastric irritant

15. Bromhexine  Synthetic derivative of vasicine (Vasaka) M.O.A  Depolymerization of muco polysaccharide  Increasing lysosomal enzyme activity  ↑ volume & ↓ viscosity of sputum S/E  GIT upset, rhinorrhea,lacrimation Dose 8 mg TDS MUCOLYTICS

16. Ambroxol  Metabolite of bromhexine  Similar properties  Dose 15-30 mg TDS MUCOLITE 30 MG TAB Dornase alfa  Human recombinant DNAse  Cleaves DNA  Useful in Cystic fibrosis  Given by inhalation  Dose 2.5mg OD

17. Acetyl cysteine M.O.A  Reduce viscosity of sputum by opening disulfide bond of mucoprotein S/E  Nausea,vomiting,stomatitis,bronchospasm,rhinorrhea  Dose 200mg  Administer directly to respiratory tract

18. Treatment approach

19. Drugs in Market • • • • • ASCORIL-C : Codeine, Chlorpheniramine . Ascoril –LS: levosalbutamol,Ambroxol , Guaiphenesin Ascoril –D: dextromethorphan,CPM,phenylephrine B ENADRYL : Diphenhydramine, Ammonium chloride, Sodium citrate, Menthol . .

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