First Aid: Pharmacology Flashcards
What are histamine-1 blockers?
What is the clinical use of their first-generation drugs?
They are reversible inhibitors of H1 histamine receptors
They are clinically used for allergies, motion sickness and for sleep aid
What are some adverse effects of first-generation histamine-1 blockers? Name two examples
Sedation, antimuscarinic, anti-alpha-adrenergic
Examples: doxylamine, diphenhydramine
What is the clinical use of second-generation Histamine-1 blockers and how do their effects compare to first-generation?
Used for allergies, they are far less sedating than the 1st generation due to decreased entry into the CNS
What is the role of Guaifenesin? What doesn’t it do?
It is an expectorant that thins the respiratory secretions (mucus) in order to promote mucus drainage! It doesn’t suppress the cough reflex
What is the normal job of a drug that is an ‘expectorant’
They promote the secretion of sputum by the air passages, used to treat coughs.
What is N-acetylcysteine’s mechanism of action and what else can it be used to treat?
It is a mucolytic; liquifies mucus in chronic bronchopulmonary diseases like COPD and CF by disrupting the disulphide bonds
It can also be used as an antidote for acetaminophen/paracetemol overdose
What is dextromethorphan? What effect does it have in excess and what can be given for overdose?
It’s an antitussive (antagonizes NMDA glutamate receptors) and relieves coughs because of cold or influenza. It has a mild opioid effect in excess and naloxone can be given if there is an overdose.
What is the mechanism and clinical use for pseudoephedrine and phenylephrine?
They are alpha-adrenergic agonists that reduce hyperemia and edema (used as nasal decongestants) that open obstructed Eustachian tubes
What does the eustachian tube do?
Connects the middle ear to the nasopharynx and controls the pressure in the middle ear (making it equal to atmospheric pressure)
What are some adverse effects of pseudoephedrine and phenylephrine?
Hypertension
Rebound congestion (constant nasal stuffiness from the overuse of nasal sprays (containing a decongestant medicine)) if used for more than 4-6 days
Can also cause CNS stimulation/anxiety (pseudoephedrine)
Name three drugs used in pulmonary hypertension
- Endothelin receptor antagonists
- PDE-5 inhibitors
- Prostacyclin analogs
Name two examples of second-generation histamine-1 blockers
Loratadine, fexofenadine
What drug can cause serotonin syndrome if combined with other serotonergic agents?
Dextromethorphan
What is the mechanism of endothelin receptor antagonists? Name one example
Mechanism: competitively antagonizes endothelin-1 receptors which decrease pulmonary vascular resistance
BosENtan
What is an important ‘clinical note’ of endothelin receptor antagonists?
They are hepatoxic and LFTs should be monitored
What is the mechanism of PDE-5 inhibitors, what else can they be used for other than treating pulmonary hypertension? Name one example.
Inhibit PDE-5 (which normally degrades cGMP) -> this leads to an increase in cGMP and a prolonged vasodilatory effect of NO and can also be used to treat ED!
Example: sildenafil
When are PDE-5 inhibitors contraindicated and why?
When taking nitroglycerin or other nitrates due to the risk of severe hypotension
What is the mechanism of prostacyclin analogs?
PGI2 (prostacyclin) has a direct vasodilatory effect on the pulmonary and systemic arterial vascular beds, it inhibits platelet aggregation
Name two side effects and two examples of prostacyclin analogs
Side effects: flushing, jaw pain
Examples: epoprostenol, iloprost
What pathways are targetted in asthma drugs?
Inflammatory process and parasympathetic tone are targetted to mediate asthmatic bronchoconstriction
Name eight examples of asthma drugs!
AAA (all antis) can better my man-crush CBMMC
- anti leukotriene
- anti-IgE monoclonal therapy
- Anti-IL-5 monoclonal therapy
- B2 agonists
- Chromones
- Inhaled corticosteroids
- Muscarinic antagonists
- Methylxanthines
Name two examples of B2 agonists? What is their individual mechanism of action? What adverse side effects can they both cause?
- Albuterol: short-acting B2 agonist that relaxes bronchial smooth muscle for acute exacerbations
- Salmeterol, (and formoterol): long-acting agents for prophylaxis
Both can cause tremor and arrhythmia `
Name two examples of inhaled corticosteroids, what is their mechanism of action?
Fluticasone and budesonide: they inhibit the synthesis of virtually all cytokines by inactivating the NF-kB transcription factor that induces the production of TNF-a and other inflammatory agents
How often are inhaled corticosteroids used to treat asthma, what should you do right after using them?
They are 1st line therapy for chronic asthma, should use a spacer or rinse mouth out after to prevent oral thrush
What is the mechanism of action for muscarinic antagonists? Name two examples
They competitively block muscarinic receptors to prevent bronchoconstriction
Examples: Tiotropium and ipratropium
What else can muscarinic antagonists be used for other than asthma?
COPD
Name three examples of antileukotrienes and their mechanisms of action
MonteLUkast and zafirLUkast: block leukotriene receptors (CysLT1)
ZiLEUton: blocks the 5-lipoxygenase pathway which blocks the conversion of arachidonic acid to leukotrienes
Which antileukotriene is hepatotoxic?
ZiLEUton
Which types of asthma are monteLUkast and zafirLUkast especially good for treating?
Aspirin or exercise-induced asthma
Name one example of an anti-IgE monoclonal therapy and describe its mechanism of action. When is it used?
Omalizumab: binds mostly to unbound serum IgE and block the binding to FC(backwards 3)RI (a high-affinity IgE receptor)
Used in allergic asthma with increased IgE level resistant to inhaled steroids and long-acting B2 agonists
Name one example of a methylxanthine drug and describe its mechanism of action, what does it block the action of?
Theophylline: likely causes bronchodilation by inhibiting phosphodiesterase, this increases cAMP levels (due to decreased cAMP hydrolysis), blocks actions of adenosine
What is adenosine and what is its role in normal function?
A neurotransmitter that promotes sleep and suppresses arousal
Why does theophylline have a limited use? How is it metabolized?
It has a narrow therapeutic index (can cause neurotoxicity and cardiotoxicity), metabolized by cytochrome P-450 enzymes
Name one example of a chromone drug and describe its mechanism of action. How often is it used?
Cromolyn; prevents mast cell degranulation to prevent acute asthma symptoms - rarely used
What is the mechanism of action of Anti-IL-5 monoclonal drugs? What are they used for?
They prevent eosinophil differentiation, maturation, activation and survival mediated by IL-5 stimulation
Used for maintenance therapy in severe eosinophilic asthma
What was IL-5 originally discovered as?
An eosinophil colony-stimulating factor
Name two examples of anti-IL-5 monoclonal drugs and what they specifically act against
Mepolizumab: against IL-5
Benralizumab: against IL-5 receptor alpha
