Drug Used for the Treatment of Cough_Dr.anila
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Transcript of Drug Used for the Treatment of Cough_Dr.anila
LEARNING OBJECTIVES• Classification of drugs used for the non
specific treatment of cough• Define the term Expectorant and
mucolytic• Describe the mechanism of action,
adverse effects and clinical uses of • Expectorants• Antitussives
Classification of drugs used for non specific treatment of cough
1. Cough suppressants• Centrally acting Antitussives• Peripheral Antitussives2. Cough expectorants3. Antihistamines4. Bronchodilators
1) COUGH SUPPRESSANTS (Anti-tussives)
1- Centrally acting Antitussives Narcotic antitussive Opiates Codeine Pholcodine Hydrocodone Non narcotic antitussives Opiates Dextromethorphan Levopropozyphene Noscapine
2- Peripheral Antitussives1 Demulcents
LinctusLozengesLiquorice
2 InhalationWater aerosol inhalationBenzoinMenthol
3 Local anaestheticsBenzonatateLignocaine (only in special circumstances)
2) Cough Expectorants 1 Drugs acting Reflexly
IpecacuanhaAmmonium chloridePotassium Iodide
2 Drugs Acting DirectlyPotassium IodideGuaiphenesin
Definition of Mucolytic and Expectorant
• Mucolytic• A mucolytic is a drug that breaks down thick
mucus, making it thinner and easier to cough out.
• Expectorant An expectorant is a drug which makes the cough
more productive by loosening and liquefying bronchial secretions.
Also known as Mucokinetics
AntitussivesAntitussives are substances that specifically inhibit or suppress the action of cough
1) Depression of medullary centre or associated higher centers.
2) Increases threshold of the cough centre.3) Interruption of tussal impulses peripherally in
the respiratory tract.4) Inhibition of conduction along the motor
pathways.
Narcotic AntitussivesCodeine and Pholcodeine An opium alkaloid similar to morphine less potent then morphine as analgesic and
respiratory depressant. 60% effective orally then parentrally as an
analgesic and respiratory depressant. A standard antitussive A small fraction of administered codeine is
metabolized to morphine which is responsible for analgesic effects of codeine.
MOA of Codeine:• Directly suppresses cough centre by binding to
distinct receptors in Medulla. • Suppresses cough for about 6 hrs. Dosage: 15 mg Adverse effects of Codeine:• In therapeutic doses minimum side effects
– Sedations, nausea, constipation• At higher doses respiratory depression and
drowsiness can occur.• Contraindicated in asthmatic patients and
patients with diminished respiratory reserves.
• Pholcodeine has similar efficacy as codeine with longer duration of action of 12hrs
• It has no analgesic or addiction property
Non Narcotic AntitussivesDextromethorphan Hydrobromide A synthetic compound. It is a dextrorotatory sterioisomer of a methylated
derivative of levorphenol. Strong and partial µ agonist. As effective antitussive as codeine. MOA:1. Controls cough spasm by depressing cough
centre in medulla2. Increase the threshold for coughing
Advantages of Dextromethorphan
– No effect on ciliary activity– No CNS depression– No addiction potential– No constipationDosage: 15- 30mg three or four times daily.
Toxicity:Toxic doses may cause.Stupor, ataxia, respiratory depression, convulsion in children and death with abuse of its purified powder.
• Contraindicated in children below 6 yrs of age and also in patients taking Monoamine oxidase inhibittors.
• Levopropoxyphene• It is a sterioisomer of weak opioid agonist
dextropropoxyphene. • It is devoid of opioid effects• Sedation is the only adverse effect• Dosage: 50-100mg 4hrly
Noscapine• An opium alkaloid• No narcotic, analgesic or dependance
inducing properties. • Equally effective antitussive as codeine• Useful for spasmodic cough.• Headache and nausea are usual side
effects• Contraindicated in asthamatic patients.
Benzonatate Chemically related to tetracaine. MOA:
Reduces the cough reflex by anesthetizing the stretch receptors in the respiratory passages, Lungs and Pleura.
It has some central effects also.Adverse effects:Headache, Dizziness, PruritusNasal Congestion, burning of eyes & tightness in chest.
EXPECTORANTSThese are the drugs which make the cough
more productive by loosening and liquefying bronchial secretions.
Also known as Mucokinetics.
Guaiphenesin It is a derivative of Guaiacol Obtained from wood or synthetically preparedMOA. Decrease sputum viscosity and increase
sputum volume thereby decreasing difficulty in expectoration
only FDA Approved expectorant . Adverse effects. Nausea, gastric disturbances
drowsiness and rash.
IPECACUANHA Source: Natural alkaloid obtained from
roots of cephaelis acuminata contains: – Cephaeline – Emetine
MOA. Loosening & liquefying mucosa soothing irritated bronchial mucosa. It also has emetic & amoebicidal properties.
• Uses. Mainly used for emesis in accidental poisoning.
• Contraindications Semiconscious, Unconscious or
convulsing person Corrosive poisoning or kerosine poisoning.
MucolyticsMOA of Mucolytics: Mucolytics open disulphide bonds in the
mucoproteins present in the sputum making it less viscid.
Bromhexine: MOA: It depolymerizes the
polysaccharides directly as well as by liberating lysosomal enzymes which breaks down the fiber network in the tenacious sputum.
Particularly useful for mucous plugs. Adverse effects: Rhinorrhoea, lacrimation, and gastric
irritation.
Antihistamines• Chlorphenaramine 2-5mg• Diphenhydramine 5-25mg• Promethazine 15-25mg• Anti histamines provides relief in cough due to
sedative and anticholinergic action.• They lack selectivity for cough centres • They have been promoted for treatment of
cough in allergic states.• No efficacy in Asthma
Bronchodilators• Bronchodilators by clearing secretions
through increase in surface velocity of airflow during cough relieves .
• Should be used only when element of bronchoconstriction is present and not routinely
• Fixed dose combination of bronchodilators with anti tussives not preferred .
Special conditions Cough may be useful or useless. No role of Antitussives Asthma young infants Congestive cardiac failure Bronchiactasis, COPD, Tuberculosis.
Antitussives may be prescribed For dry unproductive cough that is
hazardous or is disturbing sleep. ( hernias, piles, after surgical procedures
esp cataract surgery). Pholcodeine along with diphenhydramine
is useful. In whooping cough or in pertusis. Bronchodilator along with
Diphenhydramine is useful.