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

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) Beta 2 Specific agonists – Short acting –Albuterol (Ventolin, Proventil) 2.5 mg in 3 mL NS –Metaproterenol (Alupent) –Terbutaline (Brethine)

16. Bronchodilators, cont. Inhaled Beta 2 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 Alpha 1 agonist –Phenylephrine –Pseudoephedrine –Phenylpropanolamine Administered as mist or drops Side Effects – rebound congestion (use greater than 7 days)

31. Antihistamines Blocks histamine receptors Common 1 st generation – cause sedation –Chlor-Trimeton –Benadryl –Phenergan Common 2 nd 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 beta 1 and beta 2 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 O 2 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