11 Drugs For Allergy and Asthma

Question 1

antihistamine MOA and use

Answer 1

• • reversible competitive antagonism of histamine at H1 receptors
• for mild allergic rxns

Question 2

why aren’t H1 antagonists effective in true anaphylaxis/asthma?

Answer 2

• don’t block CV H2 receptors

- don’t control lipid mediators (eg. LT)

Question 3

antihistamines distribution

Answer 3

• 1st gen - body, CNS

- 2nd gen - not in CNS

Question 4

antihistamines pharmacodynamics

Answer 4

• action at various receptors
• • H1
• • muscarinic cholinergic
• • alpha adrenergic
• • serotonin
• • local anesthetic receptor sites

Question 5

clinical effects of antihistamines

Answer 5

• antiallergic
• • blockade of peripheral H1 receptors
• sedation/sleep aids
• • blockade of H1 and M receptors in CNS
• antinausea/antiemetic actions
• • blockade of D2 receptors in CTZone

Question 6

adverse effects of antihistamines

Answer 6

• cholinergic receptor blockade
• • urinary retention, pupillary dilation*****, blurred vision, dry mouth, constipation, increased HR
• adrenergic receptor blockade
• • orthostatic hypotension
• local anesthesdia
• • block Na+ channels
• CNS depression
• • sedation

Question 7

antihistamine toxicity, tolerance, interactions

Answer 7

• tox
• • blurred vision
• • mouth dryness
• • urinary retnetion
• • constipation
• • CNS depression
• • potentiation of CNS depressants
• tolerance develops with chronic use
• interactions with MAO inhibitors, erythromycin/ketoconazole, CNS depressants, anticholinergics

Question 8

purpose of asthma treatments

Answer 8

• decrease bronchospasm

- anti-inflammation

Question 9

2 types of bronchodilators

Answer 9

• b2 agonists

- muscarinic antagonists

Question 10

• 3 eg. b2 agonists (aerosols) - bronchodilator
• MOA
• use

Answer 10

• eg. albuterol - short acting
• eg. salmeterol - long acting
• eg. indacaterol - ultra long lasting (24 hour)
• smooth muscle relaxation –> bronchodilation
• for acute asthma

Question 11

• 1 eg. muscarinic antagonist - bronchodilator
• MOA
• use

Answer 11

• eg. ipratropium
• targets parasympathetic nerves of bronchial smooth muscle
• blockade of muscarinic receptors –> decreases contraction of airway smooth muscle and decreases mucus secretion
• only inhibits vagal-mediated bronchoconstriction
• for unresponsive px
• COPD

Question 12

2 types of anti-inflammatory agents

Answer 12

• release inhibitors

- glucocorticoids

Question 13

• 1 eg. release inhibitor - anti-inflammatory agent
• MOA
• use
• toxicity

Answer 13

• eg. cromolyn
• decrease release of mediators
• prophylactic (prevents asthma) - for exercise-induced asthma
• no effect on smooth muscle tone or bronchospasm
• limited tox - use in children

Question 14

• glucocorticoid - anti-inflammatory agent
• MOA
• use
• toxicity

Answer 14

• lipid-soluble glucocorticoids

- blocks PLA A2
decreases AA metabolites
- decreases cytokines
- decreases chemoatraction of eosinophils
- increases sensitivity of b receptors

• used when non-responsive to bronchodilators
• inhaled
• tox
• • rare adrenal suppression
• • oral yeast infection

Question 15

• 1 LT receptor antagonist eg.

- effects

Answer 15

• eg. zafirlukast
• antagonist of LTB4, D4C4E4 receptors and blocks effects
• decreases inflammation & bronchoconstriction
• decreases astham sx and need for b2 agonists & glucocorticoids (sparing effect)
• used in combo with other rx
• few side effects