Drugs for asthma

Assist.Professor Obs. And Gynae um Jhalawar Nursing College, Jhalawar (Raj)
6. Jun 2020

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Drugs for asthma

  2. TREATMENT APPROCHES 1. Prevention of antigen and antibody reaction. 2. Neutralization of IgE. 3. Suppression of inflammation and bronchial hypereactivity. 4. Blockage of constrictor neurotransmitter by giving anti- cholinergics. 5. Prevention of release of inflammatory mediators. 6. Dilatation of bronchiols.
  4. BRONCHODILATORS 1) Sympathomimetics or β-Adrenergic Agonists a) Non- selective- β-agonists Epinephrine, ephedrine, isoprotenerol b). Selective β-agonists - Salbutamol, terbutaline, metaproterenol, salmeterol, formaterol etc. 2) Methylxanthine- Theophylline, Aminophylline, Hydroxy ethyl, theophylline,doxophylline.
  5. Sympathomimetics or β-Adrenergic Agonists M.O.A- 1. Relax smooth muscles by stimulate β-receptors. 2. Inhibit release of inflammatory mediator or broncho constricting substances from mast cells. 3. Increase mucociliary transport
  6. a) Non-selective β- agonists • Cause more cardiac stimulation ,they should be reserved for special situation.  Epinephrine: – very effective, rapidly acting especially preferable for the relief of acute attack of bronchial asthma. – Administered by inhalation or subcutaneously.  Ephedrine: • Compared to epinephrine, it has longer duration of action but more pronounced central effect • It can be given orally.
  7. b) Selective β2- selective agonists  Largely replaced non – selective β2- agonists, are effective after inhaled or oral administration and have got longer duration of action.  Most widely used sympathomimetics.  Commonly used drugs both by oral and inhalation are Salbutamol, terbutaline, metaproterenol, pirbuterol and bitolterol.  Salmeterol and formeterol are new generation, long acting β2- selective agonists (with duration of action 12 hrs or more).  Through inhalation results in the greatest local effect on airway smooth muscle.
  8. DRUG DOSES & EXAMPLES (SYMPATHOMIMETICS) S.N DRUGS DOSE 1. Salbutamol 2-4 mg oral 2. Terbutaline 5 mg oral 3. Formoterol 80 mcg oral 4. Albuterol 200-400 mcg inhaled every 6 hr.
  9. Side effects • Tremors, anxiety, insomnia, tachycardia, headache, nervousness, tachycardia, hypertension and etc. Contraindications: • Hypersensitivity to the drugs • arrhythmias Precautions: • Used cautiously in patients with hypertension, cardiac dysfunction, hyperthyroidism, glaucoma, diabetes, pregnancy.
  10. METHYLXANTHINES • The theophylline preparations most commonly used for therapeutic purposes is aminophylline. Mechanism of Action-  Inhibit the release of histamines and leukotriens from the mast cells , the theophylline is most selective in its smooth muscle effect.  They competitively inhibit the action of adenosine on adenosine (A1 and A2) receptors (adenosine has been shown to cause contraction of airway smooth muscle and to provoke histamine release from airway mast cells.
  11. DRUG DOSES & EXAMPLES (METHYLXANTHINES) S.N DRUGS DOSE 1. Theophylline 200-400 mg TDS oral 2. Etophylline 250 mgTDS IV/ IM 3. Aminophylline 250-500 mgTDS IV slow
  12. MUSCRANIC RECEPTOR ANTAGONISTS (Anticholinergics) Mechanism of Action • They inhibit or block effect of acetylcholine neurotransmitter, acetylcholine cause bronchoconstriction. Adverse effects  As a result of rapid absorption include urinary retention, tachycardia, agitation and local effects like excessive dryness of mouth. ( limits the quantity of atropine used).
  13. IPRATROPIUM BROMIDE  The antimuscarinic agents appear to be more effective in chronic obstructive pulmonary diseases - more than asthma.  Antimuscranic antagonist drugs appear to be slightly less effective than β- agonists agents in reversing asthmatic bronchospasm,  They are useful as alternative therapies for patients intolerant of β – agonists.
  14. DRUG DOSES & EXAMPLES (ANTICHOLINERGICS) S.N DRUGS DOSE 1. Atropine 0.4 – 1 mg IV 2. Ipatropium Bromide 40-80 mcg 3. Diphenhydramine 25-50 mg
  15. CORTICOSTEROIDS  Corticosteroids are mainly given for patient who need urgent treatment and those who have not improved with bronchodilator. • Commonly used are hydrocortisone, predinisolone, beclomethasone. • Route by inhalation as aerosol, oral, or an IV administration  Mechanism of action- • Anti inflammatory nature by inhibition of production of inflammatory mediators. • They also potentiate the effects of β- receptor agonists. and inhibit the airway mucosal inflammation.
  16. DRUG DOSES & EXAMPLES (CORTICOSTEROIDS) S.N DRUGS DOSE 1. Prednisolone 5-60 mg/day 2. Beclomethasone Dipropionate 100 µgm 6 hrly by aerosol inhalation 3. Budisonide 400 µgm daily 4. Fluticasone 100-250 µgm by aerosol
  17. Clinical uses in bronchial asthma - Urgent treatment of severe asthma not improved with bronchodilator - Nocturnal asthma prevention - Chronic asthma Side effects: - Suppression of the hypothalamic-pituitary-adrenal axis - Osteoporosis - Sodium retention and hypertension - Cataract - Impairment of growth in children - Susceptibility to infection like oral candidiasis, tuberculosis
  18. MAST CELL STABILIZERS Mechanism of action • They inhibit mast cell activity, thus prevent release of allergic mediators like histamine, cytokines. These chemicals are essential for inflammation and allergic reactions. • It has no role once mediator is released and is used for casual prophylaxis. Side effects – Poorly absorbed so minimal side effect – Throat irritation, cough, dryness of mouth, chest tightness.
  19. DRUG DOSES & EXAMPLES (MAST CELL STABILIZER) S.N DRUGS DOSE 1. Sodium cromoglicate 20 mg 6 hrly 2. Cromolyn sodium 20 mg 4 times a day 3. ketotifen 1-2 mg
  20. ANTIHISTAMINES M.O.A-  They blocks effects of histamine and its receptors. INDICATION-  Allergic reactions.  As hypnotics, mild sedatives/anxiolytics.  As emetics SIDE EFFECTS-  Drowsiness  Dryness mouth  Blurring vision.  Urinary retention  Constipation.
  21. DRUG DOSES & EXAMPLES (ANTIHISTAMINES) S. N DRUGS DOSE 1. Diphenhydramine 25-50 mg 2. Promethazine 25-50 mg 3. Hydroxyzine 25-50 mg 4. Chlorphenarmine 2-4 mg 5. Cyclizine 50 mg 6. Cetrizine 10 mg Highly sedative Mild sedative Non sedative
  22. TREATMENT OF STATUS ASTHMATICS  Status asthmatics • Very sever and sustained attack of asthma which fails to respond to treatment with usual measures.  Management: • Administration of oxygen • Frequent or continuous administration of aerosolized ß2 agonists like salbutamol • Systemic corticosteroid like methyl prednisolone or hydrocortisone IV • Aminophylline IV infusion • Iv fluid to avoid dehydration • Antibiotics in the presence of evidence of infection
  23. DRUG INTERACTION 1. Β-blocker antagonize the effects of β- sympathomimitic and methylxanthines. 2. Erythromycin increase toxicity risk of methylxanthines. 3. Prolong use of theophylline cause additive effects. 4. Alcohol and charcol based food decrease effectiveness of drugs.
  24. NURSING RESPONSIBILITY • Monitor vital signs closely. • Teach patients how to use inhalers. • Instructs patient to avoid respiratory irritants; smoke, duct, strong smell. • To detect toxicity monitor therapeutic serum level. • Monitor adverse reactions. • Monitor intake output. • Watch sighs of urinary retention. • Instruct to rinse mouth after using inhaled steroids. • Take bronchodilator saveral minute before glucocorticoid inhaler. • Care of inhaler properly. • Give antihistamine at bed time due to sedation efects. • Avoids sedatives , hypnotics, alcohol.