Drugs that Affect the Respiratory System

1. Drugs that Affect the Respiratory System P. Andrews Chemeketa Community College Paramedic Program Fall 07

2. When do we consider respiratory medications? • Asthma • Decreases pulmonary function • May limit daily activity • Presents with • SOB • Wheezing • Coughing

3. Or, perhaps…… • SOB, unknown etiology • Allergic reaction • Pneumonia • Congestive heart failure • Emphysema • Others…..?

4. Asthma, cont. • Has numerous components! • Bronchoconstriction • Inflammation • Edema • Mucus hypersecretion • And others…. • Usually an allergic reaction

5. Bronchodilators Beta2 specific agonists (short-acting) Beta2 specific agonists (long-acting) Methylxanthines Anticholinergics Glucocorticoids Leukotriene antagonists Mast-cell membrane stabilizer Categories of respiratory meds

6. Advantages of Nebulized Meds. • Smaller doses • Onset Rapid • Targeted delivery • Less side effects

7. Disadvantages of Inhaled Meds • Variables in delivery • Usage variables • User • Caregiver • Requires delivery to lungs • Not always adequate depth of respiration

8. Remember This? • Absorption • Distribution • Metabolism • Elimination

9. Absorption and Distribution • Absorption • Ionized drugs (Ipratropium) • Absorb poorly • Won’t distribute well to body • Mostly local effect • Used for AEROSOL • Non-Ionized drugs (Atropine) • Absorb well • Distribute well • Systemic Effect • Poor Aerosol Drug

10. Quick Review of Receptors • Sympathetic • Adrenergic • Epinephrine or Nor-epinephrine • Primary neurotransmitters • Parasympathetic • Cholinergic • Acetylcholine • Primary neurotransmitter

11. Muscarinic • A drug that stimulates Acetylcholine at Parasympathetic nerve endings. • When drugs refer to muscarinic or antimuscarinic action, • It ONLY acts on Parasympathetic sites!

12. Adrenergic Stimulation • Alpha 1 • Vasoconstriction • Increase Blood Pressure • Beta 1 • Increase Heart Rate • Increase Force of Heartbeat • Beta 2 • Bronchial Smooth Muscle Dilation

13. Adrenergic Bronchodilators • Indication • Obstructive Airway Disease • Asthma, Bronchitis, Emphysema • Mode of Action • Adrenergic Receptors • Alpha 1…vasoconstriction • Beta 1…Increase HR • Beta 2…Bronchodilate (Yeah!)

14. Adrenergic Bronchodilators • Adverse Effects • Dizziness, • Nausea, • Tolerance, • Hypokalemia, • Tremors • H/A

15. Adrenergic Bronchodilators • Nonspecific agonists • Epinephrine (rarely used) • Beta2 Specific agonists – Short acting • Albuterol(Ventolin, Proventil) • 2.5 mg in 3 mL NS • Metaproterenol (Alupent) • Terbutaline (Brethine)

16. Bronchodilators, cont. • Inhaled Beta2 selective (long-acting) • Salmeterol (Serevent)

17. Anticholinergic Bronchodilators • Indication • Bronchoconstriction • Mainly in COPD • Mode of Action • Competes at Muscarinic receptors • Blocks Acetylcholine at smooth muscle • Reduces Mucus Production

18. Anticholinergic Bronchodilators • Adverse Effects • Watch for Cholinergic side effects • More with nebulized form than MDI • Examples • Atrovent (ipratropium) • 0.5 mg in 2.5 mL NS • Combivent (mixed w/ Albuterol) • 0.5 mg Atrovent & 2.5 mg Albuterol in 3 ml NS) • Atropine • 0.5 – 1 mg in 2 – 3 mL of NS • Robinul • Peak effects in 1 – 2 hrs

19. Mucus Controlling Agents • Indication • Excessive , thick secretions • As in COPD and TB • Action • Lower viscosity of mucus

20. Mucus Controlling Agents • Side effects • Irritation of Airway • Bronchospasm • Pharyngitis, voice change, laryngitis • Chest pain • Rash • Considerations • Have suction ready • Anticipate cough

21. Mucus Controlling Agents • Examples • Mucomyst (Acetylcysteine) • COPD, TB • Acetaminophen OD • Pulmozyme • Cystic Fibrosis • Nebulized Saline • Simple yet effective!

22. Inhaled Corticosteroids • Indications • Asthma • Anti-Inflammatory MAINTENANCE • Require Hours to Act! Preventative drug • Mode of Action • Modifies RNA/DNA action in Cells • Complicated Stuff

23. Inhaled Corticosteroids • Adverse Effect • Small incidence with nebulized • Oral doses have high incidence • Considerations • Not valuable in Acute Care • Watch for these in Pt Drug Lists

24. Corticosteroids • Examples • Beclovent, Vanceril • Azmacort • Aerobid • Flovent • Pulmicort • Advair® • fluticasone (steroid) and salmeterol(bronchodialator)

25. Glucocorticoids • Indications • Prophylactic treatment of Asthma • Hayfever

26. Glucocorticoids (cont) • Mode of Action • Lowers release of Histamine in Mast Cells • Lowers release of Inflammatory Response • Prevents Bronchospasm, airway inflammation • Acts in allergic and non-allergic asthma • Not a bronchodilator! • Not for use in acute setting • Controllers, not relievers

27. Glucocorticoids (cont) • Adverse Effects • Include • H/A • Nausea • Diarrhea

28. Cromolyn sodium • Similar to glucocorticoids • Adverse Effects • Only coughing or wheezing

29. Anti-inflammatory Agents, cont. • Corticosteroids - Injected • Methylprednisolone (Solu-Medrol) • Children; 0.25 mg/kg (max dose 125 mg IVP) • Adults; 125 mg IVP • Dexamethasone (Decadron)

30. Nasal Decongestants • Alpha1 agonist • Phenylephrine • Pseudoephedrine • Phenylpropanolamine • Administered as mist or drops • Side Effects – rebound congestion (use greater than 7 days)

31. Antihistamines • Blocks histamine receptors • Common 1st generation – cause sedation • Chlor-Trimeton • Benadryl • Phenergan • Common 2nd generation – does not cause sedation • Seldane • Claritin • Allegra • Caution: thickens bronchial secretions – do not use in Asthma!

32. Cough Suppressants • Antitussive meds – suppress cough stimulus in CNS • Codeine, hydrocodone

33. A couple of ‘odd’ ones

34. Epinephrine Racemic Epinephrine(microNEFRIN) • Class • Bronchodilator (adrenergic agonist) • Action • Affects both beta1 and beta2 receptors sites. Bronchodilation, reduces subglottic edema • Also increases pulse rate and strength • Also Alpha effects, vasoconstriction, Increased BP

35. Epinephrine • Indications • Croup, Epiglottitise • Bronchospasm • Absorption • Absorption occurs following inhalation • Half-life • Unknown

36. Epinephrine • Contraindications • Hypersensitivity • Precautions • Watch for Rebound Worsening • Watch ECG for changes • Increases Myocardial O2 demand • Side effects • Nervousness, restlessness, tremor, arrhythmias, hypertension, tachycardia

37. Epinephrine • Interactions • Beta blockers may negate effects • Route and dosage • Inhalation • One time Only • 1 mg Epinephrine, 1:1000 in 3 mL NS • Considerations • Give ENROUTE • ONLY if patient in Extreme Distress

38. Epi, cont. • May also consider Epi SQ • Patients who can’t cope with aerosol admin. • 0.3 – 0.5 mg SQ, then Neb treatment once patient can move air • Or Infusion; • 1 mg Epinephrine 1:1000 in 250 mL NS (concentration 4 mcg/mL) infuse at 1 mcg/min, titrating to effect

39. Magnesium Sulfate • Not usually admin. in pre-hospital setting • Can be used to treat moderate to severe asthma in patients who respond poorly to beta-agonists • Don’t use in patients with heart blocks, myocardial damage, or hypertension • 2 gm in 100 mL NS, given over 2 – 5 min.

40. Status Asthmaticus