Drugs that Affect the Respiratory System BROOKE BENTLEY, PHD, APRN

Transcription

1 Drugs that Affect the Respiratory System BROOKE BENTLEY, PHD, APRN Goals of Therapy Asthma Prevent symptoms COPD Reduce COPD symptoms Decrease use of SABAs Maintain normal pulm function & prevent loss of lung function Maintain QOL including attendance at school, work and physical activities Reduce the frequency & severity of exacerbations and reduce hospitalizations Improve health status Improve exercise tolerance Prevent exacerbations & minimize ED visits and/or hospitalizations Minimize the impact of the medications on other potential co-morbid conditions Provide optimal pharmacotherapy with minimal or no AEs 1

2 Goals of Drug Therapy 1. dilate the airways 2. reduce inflammation 3. stabilize mast cells Delivery Methods Correct use of Metered Dose Inhaler (MDI) inhaler: 2

3 Delivery Methods Dry-Powder Inhaler (DPI) Dry, micronized powder delivered directly to the lung Breathe in quickly & deeply Dose lost if patient exhales through the device Avoid moister in the device 3

4 Delivery Methods DPI: Spiriva: Single-dose capsules must be inserted into the inhaler prior to use 4

5 Nebulizer Delivery Route Converts a drug solution to a mist Mist is inhaled through a face mask or mouthpiece Face mask must have snug fit Good for children or patients unable to coordinate use of MDIs or DPIs Good for home setting Less portable when leaving home Adrenergics (Sympathomimetics) MOA: Stimulates beta 2 receptors causing the formation of camp (cyclic adenosine monophosphate) in the airway tissue which results in bronchodilation AE: (incidence & severity will depend on the receptor selectivity (beta 2 in bronchial smooth muscle = bronchodilation; beta 1 in heart = increased HR & contractility) of the drug as well as the mode of administration (oral vs. inhaled) Cardiac: Tachycardia/arrhythmias/palpitations Worsening of angina symptoms CNS: Nervousness/anxiety/insomnia Tremor 5

6 Adrenergics (Sympathomimetics) Special Considerations: Use beta 2 selective agents whenever possible to minimize side effects Use inhaled drug if possible to avoid systemic effects Avoid excessive use to avoid tolerance and possible increases in mortality rate Use with caution in patients with angina, hypertension, diabetes mellitus, or hyperthyroidism Adrenergics (Sympathomimetics) Short-Acting Beta Agonist (SABA) Rescue inhalers SABA agents should always be available for episodes of shortness of breath Not generally meant for regularly scheduled use: May increase AEs Decrease effectiveness Increase airway hyper-responsiveness 6

7 Adrenergics (Sympathomimetics) Short-Acting Beta Agonist (SABA) Asthma: if using more than 2 days/wk for symptom relief (excluding exerciseinduced bronchospasm), then poor asthma control and change in therapy is needed Using more than 2 canisters/month is dangerous (risk for death in asthma pts) Exercise-induced asthma: School age child: Rx - dispense 2?; school form (triggers, self-administer, nurseadminister, S/S distress) COPD: SABA agents may help decrease symptoms, but long acting therapy is more beneficial Adrenergics (Sympathomimetics) Common Drugs: Short-Acting Beta Agonist (SABA) albuterol Brand names: Proventil HFA, Ventolin HFA, ProAir HFA onset 5 min & duration 4 hrs PRN use for acute attacks Available forms: MDI, nebulizer Writing for refills? ***HFA = hydrofluroalkane (propellant) (chloroflurocarbon (CFC) propellant removed from market by FDA in 2008) 7

8 Adrenergics (Sympathomimetics) Common Drugs: Short-Acting Beta Agonist (SABA) levoalbuterol (Xopenex) Less cardiac side effects Longer duration = 8 hrs More expensive Available forms: Nebulizer Metered Dose Inhaler (MDI) Adrenergics (Sympathomimetics) Long-Acting Beta Agonist (LABA) Maintenance inhalers (maintain symptom relief) Help decrease exacerbations and related hospitalizations NEVER used as monotherapy with asthma patients If patient on inhaled LABA & corticosteroid, then use combo product to increase adherence 8

9 Adrenergics (Sympathomimetics) Common Drugs: Long-Acting Beta Agonist (LABA) salmeterol (Serevent Diskus) formoterol (Foradil Aerolizer) Inhaled: onset 20 min & duration 12 hrs Maintenance inhaler NOT for acute attacks BLACK BOX WARNING: LABA increase risk of asthma-related deaths Anticholinergics MOA: Inhibits the effect of acetylcholine in bronchial smooth muscle when given by inhalation which results in bronchodilation NOT indicated for rescue treatment Maintenance therapy = SCHEDULED medication Primary use = COPD AEs: (systemic effects rare) Dry mouth/bad taste in mouth Blurred vision/exacerbation of narrow-angle glaucoma Urinary hesitancy/retention Cough Dizziness Sinusitis 9

10 Anticholinergics Common Drugs: ipratropium (Atrovent) Maintenance medication NOT for rescue Onset = 5-15 min Duration = 4-6 hrs Available forms: inhaler & nebulizer Combo: albuterol/ipratropium (Combivent Respimat) inhaler DuoNeb nebulizer NOT for PRN use Anticholinergics Common Drugs: tiotropium (Spiriva HandiHaler) Maintenance medication Onset = 30 min Peak = hrs Duration = 24 hrs Available forms: dry-powder inhaler QD dosing aclindinium (Tudorza Pressair) Maintenance medication Slightly faster onset of action Available forms: dry-powder inhaler BID dosing Advantage: may have less dry mouth & urinary retention; more efficacy at night 10

11 Mast Cell Stabilizers MOA: stabilize mast cells & prevent the release of bronchoconstrictive & inflammatory substances when mast cells are confronted with allergens & other stimuli Primary use: Prophylaxis tx for asthma (may take 3 wks to see full clinical effect) AEs: Hoarseness, coughing Unpleasant taste Common drugs: cromolyn inhaled nebulizer Use for asthma: QID Use for exercise induced asthma: give min prior to exercise Leukotriene Inhibitor Leukotrienes = strong chemical mediators of bronchoconstriction & inflammation; increase mucous secretion & mucosal edema MOA: selectively binds to leukotriene receptors Primary use: asthma AEs: Nausea Headache CNS: may cause aggressive behavior, hallucinations, depression, suicidality Common drugs: montelukast (Singulair) peds: may use at 6 mo of age (granule pkt) zileutin (Zyflo) common drug interactions zafirlukast (Accolate) common drug interactions 11

12 Corticosteroids MOA: anti-inflammatory effect; decreases airway edema & hyperreactivity Primary use: Asthma & COPD Available forms: MDI, DPI, nebulizer, PO (tablet & liquid), IM, IV Must be scheduled administration; NOT for PRN use Inhaled route often preferred (safe, effective, less systemic effects) Inhaled route: rinse mouth after use with water to minimize oral candidiasis Corticosteroids Available forms: MDI, DPI, nebulizer, PO, IM, parenteral PO: short-term use: burst therapy = same dose every day for a few days (ie, Prednisone 60 mg QD X 5 days) dose pack = start high dose & taper every day to lower doses Medrol dose pack (methylprednisolone)(24 mg day 1 then taper by 4 mg qd over 6 days) Dex pack (dexamethasone) (6 day, 10 day or 13 day taper) longer, individualized wean/taper (Prednisone 2-4 wks) WHY TAPER? 12

13 HPA Axis (hypothalamus, anterior pituitary, adrenal gland) Based on Diurnal Rhythm: Evening: Hypothalamus detects low levels of corticosteroids; releases corticotropin releasing hormone (CRH) Increased CRH triggers anterior pituitary to release adrenocorticotropin hormone (ACTH) Increased ACTH stimulates adrenal gland to synthesize & release corticosteroids (peak release in early morning) This is a negative feedback system If take exogenous hormones (ie, prednisone) then suppress the release of CRH & ACTH and thus, the adrenal gland is no longer stimulated to produce & secrete hormones and the gland begins to atrophy Must slowly taper exogenous hormones (ie, prednisone), so HPA axis kicks back in Stopping oral corticosteroids abruptly can lead to adrenal insufficiency or adrenal crisis and death Corticosteroids Available forms: MDI, DPI, nebulizer, PO, IM, parenteral PO: Pediatrics? prednisolone (Orapred, Prelone) oral liquid long-term use: alternate day dosing to reduce adrenal suppression & AEs Parenteral route for emergency situations: Considering admission to hospital: oxygenation low, tachypneic, tri-pod position, accessory muscles Hospital IV steroids or IM Solumedrol Nebs, pulse ox, oxygen in office for a few hours Emergent hump? 13

14 Corticosteroids Inhaled Candidiasis Hoarseness Cough Headache Long-term use: increased pneumonia in COPD patients Oral Adrenal suppression Immunosuppressant effect Osteoporosis Hyperglycemia Muscle wasting Hypertension Possible PUD Integument thinned skin Hypokalemia & hypernatremia Inhaled Corticosteroids Common drugs: budesonide (Pulmicort) flexhaler DPI, respules for nebulizer Flexhaler minimum age of 6 yo Respules minimum age of 1 yo fluticasone (Flovent) MDI, DPI Minimum age of 4 yo beclomethasone (Qvar) MDI Minimum age of 5 yo 14

15 Combination Products LABA and Corticosteroid products: salmeterol/fluticasone (Advair) Minimum age 4 yo formoterol/budesonide (Symbicort) Age >12 yo formoterol/mometasone (Dulera) Age >12 yo NEVER for acute attack Remember adverse effects from both components Phosphodiesterase 4 (PDE4) Inhibitor MOA: selectively inhibits phosphodiesterase type 4 (PDE4), leading to increased intracellular camp (cyclic adenosine monophosphate) levels; thus reducing inflammation PDE4 inhibitors are NOT direct bronchodilators Primary use: Not a first line therapy; usually with COPD not well controlled on LABAs & anticholinergics AEs: GI: nausea, diarrhea, weight loss CNS: insomnia, anxiety, depression Metabolized by CYP 3A4 substrate (careful with CYP 3A4 inhibitors e-mycin, cimetidine, fluconazole) Common drug: roflumilast (Daliresp) 15

16 Methylxanthines MOA: exact MOA unknown; increases camp and leads to bronchodilation; mild anti-inflammatory & diuretic effects NOT a first line therapy AEs: CNS: nervousness, insomnia, tremors Cardiac: tachycardia GI: N/V, anorexia Narrow therapeutic index: 5-20 mcg/ml; frequent serum levels needed Numerous drug-drug interactions (CYP 1A2 substrate) Higher doses needed with cigarette smokers (b/c tobacco is CYP 1A2 inducer) Common drug: theophylline (Theo-24) Monoclonal Antibody MOA: inhibits IgE binding to mast cells & basophils; thus, decreasing the release of mediators of the allergic response Primary use: uncontrolled, severe, persistent asthma in pts over 12 yo (allergic component) Maxed out on high dose ICS & LABA Available form: SQ every 2-4 wks; (very expensive) AEs: Injection site rxns Headache Viral URI Common drug: omalizumab (Xolair) BLACK BOX WARNING: anaphylaxis can occur up to 24 hrs after any dose 16

17 Home Oxygen Guidelines for insurance/medicare/medicaid to pay for home oxygen DME (Durable Medical Equipment) Home concentrator (pull oxygen out of the air & concentrating it) Portable method depending on mobility May need conserving device: makes the tank last longer; breath actuated or gives pulses of oxygen Continuous flow or just HS Liters per minute/nasal cannula Humidification No smoking 17