Transcript
Page 1: Bronchial asthma pharmacology
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Objectives What is bronchial asthma?

Etiology

Pathophysiology of Asthma

Approaches to treatment

Phamacotherapy

Treatment plan

Drug delivery

Status Asthmaticus

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Bronchial Asthma

300 million people

Adult 10-12 %

Children 15%

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Bronchial Asthma

Definition: It is a syndrome

characterised by inflammation

and hyperresponsiveness of

tracheobronchial tree resulting

in reversible narrowing of air

tubes, mucosal oedema and

mucus plugging.

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Etiology

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Pathophysiology

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Pathophysiology

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Signs & Symptoms Dyspnoea

Wheezing

Cough

Limitation of activity

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Approaches To TreatmentPrevention of Ag : Ab reaction

Neutralisation of IgE

Suppression of inflammation and hyperreactivity

Prevention of release of mediators

Antagonism of released mediators

Blockade of constrictor neurotransmittor

Mimicking dilator neurotransmittor

Directly acting bronchodilators

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Drugs used in Asthma

Bronchodilators

• β2 agonists

• Methylxanthines

• Anticholinergics

Anti-inflammatory

agents

• Corticosteroids

• Chromones

• Lukasts

• 5-LOX inhibitor

• Antihistaminics

• 5-HT antagonists

Miscellaneous

• Mucolytics

• Antibiotics

• Monoclonal antibodies

• Desensitization

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Bronchodilators

β2

agonistsSABA:

• Salbutamol

• Terbutaline

LABA:

• Salmeterol

• Formeterol

Methylxanthines

Theophylline

Anticholinergics

Tiotropiumbromide

Ipratropiumbromide

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β2 sympathomimeticsACTIONS:

Bronchodilatation

Inhibits mediator release

Increase mucus clearance

β2 receptor stimulation

Increased cAMP

Relaxation of bronchial muscle

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β2 Agonists

SABA

• Salbutamol, Terbutaline

• Maximum effect in 30 min

• Duration of action 4-6 hrs

• Used on ‘as needed’ basis

LABA

• Salmeterol, Formoterol

• Duration of action 12 hrs

• Used regularly

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β2 agonists

ADRs

Muscle tremors

Palpitation,restlessness

Ankle edema

Throat irritation

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MethylxanthinesTheophylline

Bronchodilatation

release of mediators

Narrow margin of safety

Ideal for night time symptoms

OTHER USES

COPD

Apnoea in premature infants

Mechanism of Action

adenylylcyclase

ATP

cAMP

5 AMP

Phosphodiesterase

Theophylline

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Adverse effectsGastric pain, vomiting

Tremors, palpitation

Hypotension

Convulsions

Insomnia

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Drug Interactions agents inducing metabolism

smoking

phenytoin

rifampicin

agents inhibiting metabolism erythromycin

OCPs

ciprofloxacin

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AnticholinergicsIpratropium bromide, Tiotropium bromideACTIONS:

Relaxes bronchial smooth muscle

may increase mucociliary clearance

act in larger airways

less effective than sympathomimetics

suitable for prophylactic use

combination is useful

very few side effects - safe

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Mechanism of Action

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Anti-inflammatory Agents

Corticosteroids

Inhalational:

• Beclomethasone

• Flunisolide

• Budesonide

Systemic:

• Hydrocortisone

• Prednisolone

• Methyl prednisolone

Chromones

Cromolyn sodium

( MDI )

Nedocromil

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Anti-inflammatory Agents (cont..)5-HT inhibitors & Antihistaminic

Ketotifen

(Oral )

Pizotifen

Lukasts ( Oral )

Zafirlukast

Montelukast

Pranlukast

Acolade

5-LOX inhibitors

Zileuton

(oral)

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CorticosteroidsPrednisolone, BeclomethasoneADVANTAGES

more complete and sustained relief

improve airflow

Influence airway remodeling

retard progression of disease

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Mechanism of Action

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Inhaled v/s Systemic corticosteroidsINHALED SYSTEMIC

Beclomethasone, BudesonideTargeted drug delivery

Systemic side effects are less

Used as a prophylactic drug

Cannot be withdrawn abruptly – bronchial hyperreactivity

Prednisolone, HydrocortisoneSystemic side effects are marked

Used in chronic severe asthma

Can be tapered rapidly

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Inhibits degranulation of mast cells

Restricted release of mediators

Inhibition of chemotaxis

CHROMONESSod cromoglycate, Nedocromil

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Chromones contd…

Long term treatment - cellular inflammatory response

Ineffective during an attack

USES

prophylaxis in asthma

allergic rhinitis

allergic conjunctivitis

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CHROMONES

Bronchospasm

Cough

Nasal congestion

Arthralgia

Rashes

ADRs

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Leukotriene AntagonistsMontelukast and Zafirlukast

Prophylaxis of mild to moderate asthma

Alternatives to inhaled Glucocorticoids

Acceptable in children

Effective in aspirin induced asthma

Safe drugs

Mode of action

AntagoniseLTs

Inhibit receptors

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Mechanism of Action

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Anti IgE AntibodyOmalizumab

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• Inhalational• Oral• Parenteral

Drug Delivery

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Inhalational Drug Delivery SystemsMDI Dischalers Spacer

Rotahalers Nebulizer

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Green[Salmeterol]

Orange[Fluticasone]

Blue[SABA]

Brown [budesonide]

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Status AsthmaticusAcute severe life threatening form of asthma.

TREATMENT:

Hydrocortisone 100mg iv stat

Nebulized Salbutamol 2.5-5mg +Ipratropium bromide 0.5 mg

High flow O2 inhalation

Salbutamol/ Terbutaline 0.4mg im/sc

Intubation and mechanical ventilation

Antibiotics

Saline + sod. bicarbonate

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