Part 9-1 (Respiratory Pharmacology) Flashcards
Pulmonary Systemic delivery
Oral or Injection
Travel throughout body, not selective for respiratory tract
Can reach lungs through pulmonary circulation
Inhaled Meds
Much better at delivering drug directly to lungs
Local effects…fewer systemic side effects
Primary Inhalation Options
Metered dose inhaler
Nebulizer
Dry Powder Inhaler
Categories of Respiratory Meds
- Control of respiratory tract irritation and secretion
- Brochodilators
- Control of airway inflammation
- Other meds
Respiratory Tract Irritation and Secretion
Antitussives (Cough medicine)
Antihistamines
Decongestants
Mucolytics/Expectorants
Antitussives: Opioids
Suppress cough reflex at brainstem
Ex: Codeine, Dextromethorphane
Often combined with decongestants
Antitussives: Benzonatate
Has an anesthetic effect on vagal nerve endings in the airway
-Reduces effects of irritation that starts cough reflex
Antitussives primary problems
Sedation
Dizziness
GI Upset
Antitussives Rehab concerns
Overuse
Dependence
May limit productive cough effectiveness
Cough Meds in children
Cough medications offer no symptomatic relief for acute cough in children and is inappropriate in young children
Antihistamines
Block (Histamine) H1 receptor, decreases effects of histamine on upper respiratory tract
Used to treat histamine-mediated coughing, sneezing, irritation
Used for seasonal allergies and colds
Old versus New histamines
Old histamines caused profound sedation
New histamines don’t cause as much sedation due to inability to cross blood brain barrier
Antihistamines Primary Problems
Sedation
Fatigue
Incoordination
Blurred vision
Antihistamine Rehab Concerns
Sedative Effects
Dry out respiratory tract; limit productive cough
Decongestants
Stimulate Alpha-1 receptor agonists (Epinephrine)
Vasoconstrict nasal mucosa
Should be administered locally (Spray)
Oral administration may cause serious side effects
Decongestants Primary Problems
Headache, Nausea, Nervousness
Cardiovascular Stimulation
Mucolytics
Break up, decrease viscosity of mucous
Make it easier to raise and expel secretions
Expectorants
Increase production of a thinner, more liquid phlegm
Enhance effects of mucolytics
Primary Mucolytic
Acetylcysteine
Breaks up disulfide bonds in mucous, decreases viscosity
Question about efficacy; may get similar benefit from warm saline mist
This drug is an antidote for acetaminophen poisoning
Dornase Alfa
Serious Mucolytic
“DNA-ase” breaks up DNA that has been released from inflammatory cells
DNA makes mucous very viscous
Very helpful in cystic fibrosis
Primary Expectorants
Guaifenesin: Increases fluid content of phlegm
Found in many OTC products
Mucolytics and Expectorants Primary Problems
May have nausea, vomiting, irritation of mouth with excessive use
Mucolytics and Expectorants Rehab concerns
No major concerns
Beneficial during postural drainage, vibration, percussion
Bronchodilators
Beta-Adrenergic Agonists
Xanthine Derivatives
Anticholinergics
Beta-Adrenergic Agonists
Stimulate beta-2 receptors on smooth muscle
Increase intracellular production of cAMP
cAMP initiates smooth muscle relaxation
Types of beta-agonists
Nonselective: Activates all beta receptors (Epinephrine)
Selective: Activate beta-2 only (Albuterol)
Beta-Adrenergic Agonists problem
Can cause bronchial irritation/constriction
Cardiac stimulation
CNS stimulation
Beta-Adrenergic Agonists Rehab Concerns
Use before postural drainage
Look for signs of overuse
Xanthine Derivatives
Drugs that are chemically similar to caffeine
Common Examples
-Theophylline
-Aminophylline
Theophylline
Powerful bronchodilator Exact mechanism of action unclear -Inhibit cAMP breakdown -Block adenosine stimulation -Inhibit intracellular Calcium release -Anti-inflammatory effects
Theophylline toxicity
Toxicity begins if plasma levels >15 micrograms/mL;serious if >20 mg/ml
Therapeutic range is 10-20 micrograms/ml
Signs: Nausea, confusion, irritability, restlessness, cardiac arrhythmias, seizures
Theophylline toxicity risk factors
If metabolism is impaired
- liver disease
- congestive heart failure
- pt age >55
- Use of other drugs
Anticholinergic drugs
Acetylcholine stimulates bronchial smooth mm contraction Drugs block receptors Ex: -Ipratropium -Tiotropium
Anticholinergic drugs effects
Tolerated well at lower doses (Early stages of COPD)
High doses: Dry mouth, constipation, tachycardia, confusion