Respiratory Flashcards
Beta2 Receptor Agonists: Albuterol
(Proair, Ventolin, Proventil)
Selective beta2 agonists with minor beta1 activity
Short-acting
Beta2 Receptor Agonists: Salmeterol
(Serevent)
Long-acting
More selective for beta2 receptors compared with albuterol and have minor beta1 activity
12 hour half life
Beta2 Receptor Agonists: Precautions and Contraindications
- Cardiac arrhythmias
- Diabetes: potential drug-induced hyperglycemia
- Long-acting beta agonists:
- —Black box warning: the risks of salmeterol and formoterol (foradil) outweigh the benefits & should not be used singly in asthma for all ages
- —Twofold increase in catastrophic events (asthma-related intubations & death)
- Terbutaline pregnancy category B (Others category C)
- Children
- —Albuterol safe for children of all ages
- — Salmeterol should not be used in children younger than age 4 years and never singly
Beta Agonsits: ADRs
Usually transient
Tachycardia and palpitations
Some central nervous system (CNS) excitation effects
- Tremors, dizziness, shakiness, nervousness, and restlessness
Headaches
Salmeterol and other long-acting B2RAs increase risk of exacerbation of severe asthma symptoms if patient is deteriorating
Beta Agonists: Drug Interactions
Digitalis glycosides: increased risk of dysrhythmia
Beta adrenergic blocking agents: direct competition for beta sites resulting in mutual inhibition of therapeutic effects
- Including beta blocker eye drops
Tricyclic antidepressants (TCAs) & monoamine oxidase inhibitors (MAOIs) potentiate effects of beta agonist on vascular system
Beta Agonists: Clinical Use
Bronchodilators are used primarily in the treatment of bronchospasm associated with asthma, bronchitis (acute or chronic), and COPD
Albuterol metered dose inhaler (MDI) dose is 2 puffs every 4-6 hours
- Dose via nebulizer is 2.5 mg/dose
- May be repeated twice after 5-10 minutes
- May be combined with ipratropium
Levalbuterol via nebulizer every 4-6 hours
Salmeterol DISKUS: 1 puff twice a day– do not use alone for persistent asthma; combine with an inhaled corticosteroid
Exercise induced bronchospasm (EIB)
- Albuterol 2 puffs 15 minutes before exercise
- Salmeterol 2 puffs 30-60 minutes before exercise— do not use if already on daily dose
- Leukotriene modifiers taken daily may decrease EIB symptoms in 50% of patients but patient will still need to use albuterol before exercise
Beta Agonists: Rational Drug Selection
The Expert Panel 3 says ay short-acting beta agonist can be used in adults
Age
- Only albuterol and metaproterenol are approved for use in children younger than 4 years of age.
- Albuterol is the safest to use in infants
Cost
- Albuterol is the least expensive
Beta Agonists: Patient Education
Metered-dose inhaler (MDI) use
- Demonstrate and have patient do return demonstration
- Check correct inhaler use if patient says the inhaler is not working
- Use a spacer with all patients
Breath-actuated inhalers require inspiratory drive to deliver medication to lungs
Xanthine Derivatives: Theophylline and Caffeine Pharmacodynamics
- Bronchial smooth muscle relaxation
- CNS Stimulation
- Cardiovascular effects
- Increased Gastric acid production
- Stimulation of skeletal muscle
- Increased renal blood flow and glomerular filtration rate
Xanthine Derivatives- Theophylline: Pharmacokinetics
Absorbed rapidly and completely from GI tract
Distributed widely
- Volume of distribution altered in: premature neonates, older patients, cirrhosis, pregnant women (third trimester), and critically ill patients, probably because of altered protein-binding
Metabolized extensively in liver via CYP450 into caffeine
- Disease states and CYP inducers can influence metabolism of theophylline
Eliminated renally
Xanthine Derivatives- Theophylline: Precautions & Contraindications
Monitor patients with HTN, ischemic, heart disease, coronary insufficiency, CHF, or a hx of stroke and cardiac arrhythmias
Monitor for theophylline toxicity
Prolonged clearance and half-life in neonates and older adults
Pregnancy Category C
Xanthine Derivatives- Theophylline: ADRs
- Toxicity with levels greater than 20 mcg/mL
- Some patients have seizures at 15-20 mcg/mL
- CNS effects: irritability, restlessness, seizures, insomnia
- GI effects: reflux, worsening heartburn
- Cardiac effects: palpitations, tachycardia, hypotension, life-threatening arrhythmias
- Toxicity (greater than 20 mcg/mL): N/V, diarrhea, HA, insomnia, & irritability
- Toxicity (greater than 35 mcg/mL): hyperglycemia, hypotension, cardiac arrhythmias, tachycardia, seizures, brain damage, death
Xanthine Derivatives- Caffeine: ADRs
Cardiac arrhythmias Tachycardia Insomnia Agitation Irritability HA N/V Gastric Irritation
Xanthine Derivatives- Theophylline: Drug-Food Interactions
- Many drug interactions are caused by metabolism via CYP450 isoenzyme CYP1A2, CYP2E1, and CYP3A3/4
- Smoking tobacco increases clearance
- Benzodiazepines are antagonized by theophylline
- Beta agonists may cause additive toxicity
- Lithium levels are reduced
- Low-carb/high-protein diet increases clearance
- Charcoal-broiled foods accelerate the hepatic metabolism of theophylline
Xanthine Derivatives- Caffeine: Drug Interactions
Caffeine metabolized via CYP450 isoenzyme CYP1A2, CYP2E1, and CYP3A3/4
Impaired caffeine metabolism: cimetadine, ketoconazole, fluconazole, mexiletine, and phenylpropanolamine
Caffeine elimination may be increased by co-administration of phenobarbitol and phenytoin
Xanthine Derivatives- Theophylline: Clinical Use & Dosing
Second- or third-line drug for asthma and COPD
Adults started on 6 mg/kg/24 hours and dose increased by 25% every 3 days until serum theophylline levels are 10-20 mcg/mL
Maximum dose in adults is 13 mg/kg/day
Children age 5 years or older: 16 mg/kg/day, max 400 mg/day
- 1 to 9 years: max dose 24 mg/kg/day
- 9 to 12 years: max dose 20 mg/kg/day
- 12 to 16 years: max dose 18 mg/kg/day
Apnea of Prematurity: Treatment
Caffeine citrate 10-20 mg/kg
- Maintenance dose of 5 mg/kg per day
Theophylline dose
- Loading dose of 4 mg/kg per dose
- Maintenance dose of 4 mg/kg per day in the premature infant or newborn up to age 6 weeks
Xanthine Derivatives- Theophylline: Rational Drug Selection
Cost and Convenience
Immediate release
- Use at beginning of therapy to determine daily dose
- Once stabilized on immediate release, transition to extended release once the total 24-hour dose has been determined
Timed release
- Taken daily at the same time
Xanthine Derivatives- Theophylline: Monitoring
Monitor for signs of toxicity
Draw frequent levels when dose is being titrated
After steady state, draw levels every 6 to 12 months
Draw levels whenever any new drug is added or deleted from regimen
Xanthine Derivatives- Theophylline: Patient Education
Take medication exactly as prescribed
Discuss signs & symptoms of toxicity
- N/V, insomnia, jitteriness, HA, rash, severe GI pain, restlessness, convulsions, or irregular heartbeat
Avoid large amounts of caffeine containing beverages
Explain that theophylline elimination is influenced by diet
Inhaled Anticholinergics
Ipratropium bromide (Atrovent) - Blocks muscarinic cholinergic receptors
Tiotropium bromide (Spiriva) and Aclidinium bromide (Tudorza Pressair) - Inhibits muscarinic M3 receptors in lungs
All cause bronchial smooth muscle relaxation
Anticholinergics: Precautions and Contraindication
Known hypersensitivity
Not used for acute bronchospasm
Ipratropium bromide is pregnancy category B and tiotropium is pregnancy category C
Not approved for use in children younger than age 12 years
- Expert Panel 3 guidelines state ipratropium may be used in children as an adjunct to beta agonist (albuterol) therapy in acute exacerbations of asthma
Inhaled Anticholinergics: ADRs
Cough is most common
Dry mouth
Mild anticholinergic effects in a few patients
- Constipation
- Urinary retention (less than 2%)
Rare allergic reaction
- Allergy to soybeans, legumes, or soy lecithin appears to be correlated with hypersensitivity to ipratropium bromide
Inhaled Anticholinergics: Clinical Use & Dosing for COPD
- Ipratropium: 2 puffs (36 mcg) 4 times/day (max 12 puffs/day)
- Ipratropium: 1 unit dose via nebulizer 3-4 times/day, may be mixed with albuterol
- Ipratropium-albuterol combination (combivent): 2 puffs 4 times/day
- Tiotropium (spiriva): 2 puffs of a single capsule once/day
- Aclidinium bromide (Tudorza Pressair): 1 puff twice/day
Inhaled Anticholinergics: Clinical Use & Dosing for Asthma
Ipratropium for asthma maintenance is 2-3 puffs 4 times/day for adults
- Children age less than 12 years: 1-2 puffs every 6 hours
Ipratropium-albuterol combination (Combivent) is a second-line quick relief medication in treatment of asthma
Tiotropium and aclidinium are not indicated for the treatment of asthma
Inhaled Anticholinergic: Cost and Patient Education
Cost
- Combined albuterol-ipratropium products are cheaper than the two individual drugs
- —–Generic ipratropium/albuterol nebulizer solution is $32 for a month’s supply
- Tiotropium (Spiriva) costs $415 per month
- Aclidinium bromide (Tudorza Pressair) costs $2360 per month
Patient Education
- Use as prescribed
- Be educated on use of inhaler or handihaler
- Rinse mouth after inhaling medication
Leukotriene Modifiers: Pharmacodynamics
- Induce numerous effects that contribute to inflammatory process
- Smooth muscle contractions
- Leukotriene-Receptor Agonists
- —Zafirlukast & Montelukast
- 5-Lipoxygenase Pathway Inhibitors
- —- Zileuton
Leukotriene Modifiers: Precautions
Do not do the following:
- Use for primary treatment of acute asthma attack
- Abruptly substitute for inhaled or oral steroids
- Prescribe for lactating women
Zafirlukast: patients with hepatic dysfunction
Leukotriene Modifiers: Contraindications
Zafirlukast and Montelukast: hypersensitivity
Chewable montelukast: patients with phenylketonuria
Zileuton: patients with active liver disease
Leukotriene Modifiers: ADRs
Most Common: HA
Less Common:
- GI upset
- Myalgias
- Fever
- Increase in respiratory infections
Leukotriene Modifiers: Clinical Use and Dosing
Zafirlukast - chronic asthma: 5 years
Montelukast
- Persistent asthma: 12+ months
- Exercise induced bronchoconstriction: 15 years
Zileuton
- Persistent asthma: 12 years
Leukotriene Modifiers: Monitoring
Worsening asthma symptoms
Bronchodilator use
Pulmonary function
New onset of neuropsychiatric symptoms
Leukotriene Modifiers: Patient Education
Take as prescribed
Do not take if pregnant or nursing
Watch for drug interactions
Watch for neuropsychiatric events
Leukotriene Modifiers: Lifestyle Management
Self-monitor respiratory status with a peak flow meter
Avoid or quit smoking
Avoid environmental triggers of asthma at home, work, and school
Corticosteroids: Benefits
Reduced severity of asthma
Increased peak flow readings
Decreased airway hyperresponsiveness
Safe and Well tolerated at recommended dosages
Inhaled Corticosteroids: Precautions
Avoid if using for:
- Relief of acute bronchospasm
- Substitute for oral corticosteroids
Avoid if patient is is/has:
- Cushing’s Syndrome
- Pregnancy
- Herpes
- TB
- Nasal trauma or ulcers
- Untreated respiratory infection
Corticosteroids: Drug Interactions
Known
- Ritonavir: increases fluticasone serum concentrations
- Ketoconazole: increases plasma concentration of fluticasone and budesonide
Unknown
- Inhaled triamcinolone, flunisolide, mometasone, beclomethasone, or ciclesonide
Corticosteroids: Clinical Use and Dosing
Asthma:
- Persistent: Inhaled corticosteroids
- Mild: low dose
- Moderate: daily low- to medium-dose inhaled combined with long-acting beta agonist
- Severe: daily high-dose and long-acting beta agonists
Allergic Rhinitis:
- Used to manage seasonal or perennial allergies
- Intranasal 1-2 times daily
Inhaled Corticosteroids: Monitoring
Patients using normal dose
- Adverse effects of the medication
- Effectiveness of the medication
- The asthma disease process
Patients using high dose for long time
- Blood glucose and potassium
Corticosteroids: Administration
Inhaled
- Use spacers
- Rinse mouth with water after each use
Intranasal
- Clear nasal passages of mucus
- Rinse mouth with water after each use
Corticosteroids: ADRs
Xerostomia (dry mouth) Hoarseness Tongue and mouth irritation Flushing Dysgeusia (altered taste sensation) Dysmenorrhea
Less common- oral candidiasis; cataracts; bronchospasm; hypothalamic-pituitary-adrenal axis (HPA) suppression; pulmonary infiltrates with eosinophilia; nasal irritation, itching, sneezing, dryness; bloody nasal mucus or epistaxis
Corticosteroids: Lifestyle Management
Self-monitor respiratory status
Avoid or quit smoking
Avoid environmental triggers of asthma at home, work, and school
Oxygen: Precautions and Contraindications
Avoid Smoking
Use lowest possible concentration: sudden increase in partial pressure of carbon dioxide (PaCO2) can stop respiration
Oxygen: ADRs
Dry nasal passages
- Most common; can be prevented
Toxicity
- Occurs when oxygen concentration is greater than air
- Death can occur
Oxygen: Clinical Use and Dosing
Clinical Use
- Treats hypoxia but is not curative
Dosing
- Goal: Maintain oxygen saturation above 90%
- Delivery: NC, mask, hood or tent
Oxygen: Monitoring Methods
Arterial or mixed venous blood gas sampling
- provides additional information regarding patient status that assists in treatment
Pulse oximetry
- Measures the difference in absorption of light
- Measures hemoglobin saturation and not partial pressure of oxygen (PO2)
Oxygen: Lifestyle Management
Avoid or quit smoking
Avoid exposure to viral respiratory infections
Avoid high altitudes
Consult with provider before traveling by air
Antihistamines: Uses
Reduce or prevent physiological effects of histamine at the histamine 1 (H1) receptor site
Strongly block the action of histamine
Decrease the flare-and-itch response
Antihistamines: Generations
First Generations (1940s) - Diphenhydramine: still widely used
Second Generations (1980s) - Non-sedating antihistamine: relief to allergy sufferers without drowsiness
First Generation Antihistamines: Precautions
Cautioned
- Pregnancy Category B
- Sedation and drowsiness; reduced mental alertness
Contraindicated
- Newborns and infants
Second-Generation Antihistamines: Precautions
Pregnancy
- Pregnancy categories B and C
Children
- Fexofenadine: age less than 6 years
- Loratadine: age 2+ years
- Cetirizine and desloratadine syrup: age 6+ months
First-Generation Antihistamines: ADRs
Sedation or fatigue, dizziness, HA, tinnitis, lassitude, disturbed coordination, N/V, irritability/nervousness, blurred vision, diplopia, tremors, increased/decreased appetite, epigastric distress, constipation, diarrhea, dry mouth, urinary retention, dysuria
Second-Generation Antihistamines: ADRs
Drowsiness is greatly reduced
Minimal incidence of dry mouth (5% or less)
Symptoms caused by first generation antihistamines can be alleviated by switching to second generation antihistamines
Antihistamines: Clinical Use
Respiratory allergies
Hypersensitivity reactions
Urticaria and angioedema
Nighttime sleep aid
Motion sickness/antiemetic
Antihistamines: Lifestyle Management
Avoid known allergies
Use environmental methods to control dust mites and other common allergens
Decongestants: Uses & Methods of Delivery
Uses:
- Common cold
- Allergic rhinitis
Methods of Delivery
- Liquid, tablet, capsule, nasal spray, drops
Decongestants: Contraindications
Patients on concurrent MAOI therapy
Patients with severe HTN or CAD
Oral Decongestants: ADRs
More common
- Restlessness and tremors
Less common or rare
- Transient HTN, arrhythmia, and cardiovascular collapse, with hypotension
Topical Decongestants: ADRs
- Transient stinging
- Burning
- Sneezing
- Dryness
- Local Irritation
- Rebound congestion with prolonged use
- Insomnia
- Dizziness
- Weakness
- Tremor
- Irregular heartbeat
Clinical Use for Nasal Congestion
Oral decongestant
- Temporarily relieve nasal congestion
- Promote nasal or sinus drainage
- Relieve eustachian tube congestion
Topical decongestant
- Symptomatically relive nasal congestion
- Relieve ear blockage and pressure pain
Decongestants: Short vs Long Acting
Short acting
- Better tolerated and have fewer ADRs
Long acting
- Useful for patients who require all-day or all-night relief, if patient can tolerate
Higher Dose Decongestants: ADRs
Nervousness, dizziness, or sleeplessness
Decongestants: Lifestyle Management
Maintain adequate hydration
Refrain from smoking when congested
Avoid caffeine-containing products
Antitussives: Use
Used to self-treat coughs
Exact mechanism of action poorly understood
Antitussives: Precautions
Do not use for persistent or chronic cough caused by smoking, asthma, or emphysema
Do not use if you have excessive respiratory secretions
Do not self-medicate for cough lasting longer than 7 days
Antitussives: Lifestyle Management
Increase fluid intake
Refrain from or quit smoking
Avoid respiratory irritants and people with respiratory infections
Expectorants: Guaifenesin
The only expectorant ingredient listed by the FDA panel as having scientific evidence of safety and efficacy
Aids in symptomatic treatment of cough caused by the common cold and mild upper respiratory infections
Expectorants- Gauifenesin: Precautions
Do not use for persistent cough
Do not use for cough related to heart failure or ACEI therapy
Do not use for cough with high fever or lasting longer than 7 days
Expectorants- Gauifenesin: ADRs
Most common
- GI upset, N/V
Less common
- Drowsiness, diarrhea, dizziness, rash, and HA
Expectorants- Gauifenesin: False Lab Readings
Gauifenesin may cause false readings in certain lab determinations of 5-hydroxyindoleacetic acid (5-HIAA) and vanillylmandelic acid (VMA)
Expectorants- Gauifenesin: Uses and Management
Use
- For dry, nonproductive cough with mucus in respiratory tract
Lifestyle Management
- Remain well hydrated
- Refrain from smoking
