Respiratory Drugs Flashcards
Bronchodilators, Anti-inflammatory's, & Leukotriene antagonists
Which drug classes are discussed here?
Anti-inflammatories:
- Corticosteroids
- Mast-cell
- Leukotriene Antagonists
Bronchodilators:
- B-2 agonists (Short & Long)
- Cholinergic blockers
Ab:
- Anti-IgE’s
Describe the mechanism of asthma
- Allergens activate T cells & stimulate Cytokine secretion
- Cytokines elicit 2 response; Bcells & Eosinophils (major)
Major: Eosinophils:
- Cytokines induce Eosoinophil chemotaxis, & leukotriene & chemotactic factor secretion
- Leukotrienes & other proteins induce airway inflammation & bronchospasm
Secondary: Bcells
- Bcells secrete IgE, which induces Mast Cell migration
- Allergen-IgE complexes induce Histamine, Leukotriene, & Cytokine secretion release from Mast cells
- Degranulation of factors induce Airway inflammation & bronchospasm
What is the mechanism of Action of Bronchodilation & Bronchoconstriction?
Bronchodilation is promoted by increased cAMP.
- cAMP is synthesized from ATP by Adenylyl Cyclase (AC)
- Location of B-agonists action
- cAMP is degrade to AMP by PDE
- Location of PDE inhibitors (i.e. Theophylline)
Bronchoconstriction is promoted by ACh & Adenosine
- Muscarinic inhibitors block ACh & Theophylline blocks Adenosine
Prostaglandin & Leukotrienes are synthesized from Fatty acids
Where is the regulated sites of this process?
Cortisol & SAIDs block Phospholipase A2 (converts FA’s to Arachadonic acid)
NSAIDS (ibuprofen, aspirin) blocks Cyclooxygenase (COX) (converts Arachodonic acid to prostaglandings)
Antileukotrienes block LT1 receptor
What are the types of anti-inflammatories used?
Corticosteroids (Chronic severe asthma or acute exacerbations)
Cromolyn Sodium (Mild to moderate asthma, allergic conjuctivitis, etc) (few adverse effects)
PDE inhibitors (Exacerbations of chronic bronchitis w/ chronic Obstructive pulmonary disease)
Describe Corticosteroids
Corticosteroids:
- The most efficacious antiinflammatory drugs
- Usually given by inhalation on a long-term basis to prevent asthmatic attacks.
- Orally or parenterally administered steroids are used for the management of chronic severe asthma or acute exacerbations of asthma.
Describe the Bronchodilators used
Short-acting β2-adrenoceptor agonists:
- Most efficacious bronchodilators for the treatment of acute bronchospasm.
- Albuterol, pirbuterol, and terbutaline.
Long-acting β2-agonists
- Used to prevent bronchospasm.
- Salmeterol and formoterol,
Ultralong-acting β2-agonist recently approved for once-daily administration.
- Indacaterol
•Ipratropium and tiotropium are muscarinic receptor antagonists that are primarily used to treat COPD.
A 12-year-old boy is brought to his pediatrician after a recent onset of episodes of coughing, wheezing, and shortness of breath. These episodes have occurred two or three times a week while he was playing outdoors, and they gradually subsided after he came indoors and sat down to rest. The family has a history of allergies to molds and pollens, and the boy has been taking an antihistamine for allergic rhinitis. Examination shows an alert, well-developed boy of normal height and weight who is in no distress. His vital signs and breath sounds are normal except for fine wheezes during forced expiration, and there are no signs of infection. Spirometry tests show a forced expiratory volume in 1 second (FEV1) that is 85% of the predicted value, and the boy’s peak expiratory flow (PEF) variability is 20% (normal <20%). These findings are consistent with a diagnosis of mild asthma, which was probably precipitated by exposure to allergens and by exercise. After discussing treatment options with his parents, the boy is started on a daily dose of montelukast, and an albuterol inhaler will be used to control acute episodes. The patient and his parents receive further instructions and training concerning the use of the inhaler, and he is given prescriptions and scheduled for a follow-up evaluation in 3 weeks to determine the need for additional therapy.
Asthma typically manifests with wheezing, dyspnea, and coughing and is often associated with a history of respiratory allergies. The history, physical examination findings, and FEV1 usually provide most of the information needed to diagnose and manage asthma. The patient appears to have mild asthma, which may be intermittent or persistent. Because the severity of his illness is uncertain, the patient is started on a leukotriene receptor antagonist because of its convenience, safety, and demonstrated effectiveness in children. The course of asthma is highly variable. His response to treatment and the future course of his illness will be monitored in order to determine the need for additional tests and treatments.
Describe Leukotriene inhibitors
Leukotriene inhibitors:
- Have Anti-inflammatory and bronchodilating activity and offer convenient oral therapy for the prevention of asthmatic attacks.
- Montelukast and zafirlukast are leukotriene receptor antagonists
- Zileuton is a leukotriene synthesis inhibitor.
Describe Theophylline
- Theophylline has Anti-inflammatory and bronchodilating activity and is useful for the treatment of asthma and COPD.
- The metabolism of theophylline is affected by smoking and by the concurrent administration of drugs that inhibit cytochrome P450.
- Children metabolize theophylline more rapidly than do adults.
- Theophylline levels should be monitored to ensure efficacy and prevent toxicity. Adverse effects include gastrointestinal, central nervous system, and cardiac toxicity.
What are Antitussives?
Antitussives:
- Used to suppress dry, nonproductive coughing.
- Dextromethorphan is available without a prescription, whereas codeine and hydrocodone are contained in many prescription cough preparations.
What is Allergic Rhinitis managed?
Allergic rhinitis is managed with antiinflammatory drugs (corticosteroids and cromolyn compounds), antihistamines, and decongestants.
Anti-Inflammatory drugs
Fluticasone (Flovent)
Cromolyn Sodium
Roflumilast (PDE5 inhibitor)
Bronchodilator Drugs
B-agonists: Albuterol & Salmeterol
