Respi Flashcards
Classes of drugs for sneeze
Antihistamines, decongestants, mast cell stabillizers
Why are 2nd gen antihistamines preferred over 1st gen for cough and cold treatment? (side effects, onset)
2nd gen used for allergy, no CNS effects because increased affinity for PGP pump, does not cross BBB.
Also shorter onset (1-2h) and longer DOA (12-24h).
Antihistamines: side effect
1st gen: sedative, dry mouth
2nd gen: dry mouth
Sympathomimetic agents: Class, names, MOA, ADR
Nasal decongestants
Pseudoephedrine, phenylephrine, oxymetazoline
Sympathetic NS causes blood vessels to constrict and lessen edema, these drugs act as direct alpha adrenoreceptor agonists
Hypertension, tachycardia, anxiety
Nasal glucocorticoids: Class, names, MOA
Nasal decongestants
Fluticasone, mometasone
Anti-inflammatory effects, decrease mucus secretion
Psudoephedrine, phenylephrine: Mode of administration
Oral
Cromoglicic acid: Class, MOA, ADR
Mast cell stabilizer (mucoregulator)
Targets IgE-FceRI mast cell degranulation, increases annexin a1 (anti-inflammatory).
Used for severe symptoms like 2nd line anti-inflammatory in asthma (not normal flu).
Bitter taste, may be difficult bc it’s an inhaled drug
Ipratropium: Classes, MOA, ADR
SAMA, mucoregulator
M3 receptor blocker. Used to treat mucus hypersecretion
Cough reflex pathway
Stimulation at mechano, chemoreceptors in larynx, trachea, bronchi
Carried by afferent C fibres in vagus nerve
Cough centre in medulla
Efferent fibres in vagus nerve
Respiratory muscles
Opioids: Class, name, MOA, ADR, contraindications
Antitussive (dry cough)
Codeine
Target opioid receptors in CNS cough centre to suppress cough, depress CNS by acting as agonists.
Sedation, constipation, urinary reten
Risk of substance abuse at high doses
Cannot take with alcohol (CNS depressant)
Cannot use in pts with respi insufficiency, head injury, pregnant women, children bc of underdeveloped respi centres
Non-opioids: Class, name, MOA, ADR
Antitussive (dry cough)
Dextromethorphan
Target CNS by blocking N-methyl-D-aspartate receptors to suppress cough
Risk of substance abuse at high doses (not as risky as codeine)
Nausea, drowsiness, dizziness
Types of mucoactives
Mucolytics, mucokinetics, mucoregulators, expectorants
Mucolytics: Class, name, MOA, ADR, contraindications
Mucoactives (productive cough)
-cysteines
Prodrugs. Mucus-thinning, breaks up mucus for easier expulsion
ADR: Bronchospasm, cannot use in asthmatics
Mucokinetics: Class, name, MOA, contraindications
Mucoactives (productive cough)
Bromhexine -> Ambroxol
Targets ciliary escalator, increases ciliary beat frequency to increase transportability
Contraindications: Asthmatics, caution in <6yo, cannot use <2yo
Guaifenesin: Class, MOA, ADR, contraindications
Expectorant (Productive cough)
Increase water content of phlegm by producing more respiratory liquids, promote expulsion of mucus
ADR: kidney stones
Contraindications: caution in <6yo
Pathogenesis of 2 types of asthma
Type 1 (allergic): IL-4, IL-13 produced by T helper cells stimulate B cells for more antibody production. IgE-FceRI crosslinking of mast cells lead to histamine production
Type 2 (eosinophilic): IL-5 by T helper cells stimulate eosinophil infiltration in lungs
Pathogenesis of asthma: early and late phase
early: bronchoconstriction and mucus secretion due to cytokines
late: epithelial damage and airway narrowing due to eosinophil recruitment which produce more cytokines
Morphological changes in chronic asthma
Airway remodelling due to repeated bouts of allergen exposure and immune reactions
Hyperplasia of smooth muscle and goblet cells, hence mucus overproduction and airway hypersensitivity
Why can’t LABAs be used alone for asthma maintenance therapy?
Constant use of LABA leads to tolerance, downregulation of B2 receptors over time. Dangerous because in the event of an attack, insufficient receptors for B2 agonist. ICS protects against this bc upregulates B2R expression.
Name 1 SABA, DOA
Salbutamol, 3-6h
Formoterol vs indacaterol
Both are LABAs with fast onset. Formoterol DOA is 12h but Indacaterol DOA is 24h
LABA with slow onset, lipophilic
Salmeterol
B2 Agonists: Class, names, MOA, ADR, contraindications
1st line bronchodilator for asthma
Salbuterol, Formoterol, Indacaterol, Salmeterol
Activates adenylyl cyclase, increase cAMP for smooth muscle relaxation
Tremors, peripheral vasodilation bc B2R present on blood vessels
LABAs should not be prescribed alone
Muscarinic antagonists: Class, name, MOA, ADR,
2nd line bronchodilator for asthma
Ipratroprium (SAMA), Tiotroprium bromide (LAMA)
Antagonists to M3 receptors, decrease vagus nerve-related mucus secretion and bronchoconstriction
Dry mouth, urinary retention
Methylxanthines: Class, name, MOA, ADR, contraindications
2nd line bronchodilator for asthma
Theophylline
Phosphodiesterase inhibitor, inhibits formation of AMP from cAMP. More cAMP, more smooth muscle relaxation
Cannot take with caffeine which is also a methylxanthine, will have additive effects
Narrow TI
Cysteinyl-leukotriene R antag: Class, name, MOA,
2nd line bronchodilator and anti-inflammatory for asthma
Montelukast
More anti-inflammatory as Cyst-L receptors are present on mast cells, but also a weak bronchodilator
Neurological effects, suicidal thinking
Which ICS may cause adrenal suppression?
Fluticasone
ADR of ICS
Immunosuppressant, increases risk of oral candidiasis and Cushing’s syndrome
ICS: Class, name, MOA
1st line anti-inflammatory for asthma Fluticasone, ciclesonide Decrease T cells, eosinophils, mast cells Decrease mucus secretion Decrease PLA2 Decrease COX2 (prostaglandins) Decrease 5-LOX (leukotrienes) Increase annexin A1 Increase B2R
Chemical properties of ICS (so that can be inhaled)
Low lipophilicity
Low first pass (less systemic side effects)
High receptor affinity (low dose)
5-LOX inhibitors: Class, name, MOA, ADR, contraindications
2nd line anti-inflammatory for asthma
Zileuton. 5-LOX catalyses synthesis of leukotrienes from arachidonic acid
Neurological effects, suicidal thinking
Anti-IgE monoclonal antibody: Class, name, MOA, ADR
2nd line anti-inflammatory for asthma Omalizumab Only given if pt does not respond to ICS EXPENSIVE, subq injection Potential for anaphylaxis
Anti-IL5 monoclonal antibody: Class, name, MOA, ADR
2nd line anti-inflammatory for asthma
Reslizumab
Potential for anaphylaxis
Characteristic features of COPD
Pink puffers (emphysema), blue bloaters (bronchitis) Inflammation, alveolar destruction, mucus hypersecretion
Why are muscarinic antagonists preferred over B2 agonists for COPD treatment?
Goal is to lower secretions and increase bronchodilation, by stimulating sympathetic and lowering muscarinic.
2nd line COPD drugs
ICS, methylxanthine, PDE-4 inhibitors, azithromycin
PDE-4 Inhibitors: Name, MOA, ADR
Roflumilast
Same as theophylline, but also slows down fibrosis.
Caution for hepatic impairment
Azithromycin: MOA, ADR
Has anti-fibrotic and smooth muscle relaxant properties.
Disrupts GI flora, risk of diarrhoea, nausea, vomiting, cardiac arrythmia
