Antihistamines & Corticosteroids, and NSAIDs

Question 1

Carbinoxamine, Dimenhydrinate, Diphenhydramine

Answer 1

• Ethanolamine antihistamines that have anticholinergic properties alone with H1 antagonism
• Cause sedation, carbinoxamine=slight-moderate, dimenhydrinate and diphenhydramine=marked sedation and anti motion sickness activity
• Tox-urinary retention, blurred vision. nonallergic rhinnorea
• Diphenhydramine can be used as an antiparkinsonism drug and as local anesthetic w/promethiazine

Question 2

MOA of antihistamines

Answer 2

All are H1 antagonists, so their effects are mediated via H2 receptors

Question 3

Hydroxyzine, cyclizine, meclizine

Answer 3

• Piperazine antihistamines
• cause sedation
• cyclizine is the best antihistamine for motion sickness
• meclizine is long acting

Question 4

Brompheniramine, chlorpheiramine

Answer 4

-alkylamine antihistamines that cause slight sedation

Question 5

promethazine

Answer 5

• H1 blocker with less anti-motion sickness action and more sedative and autonomic effects
• has an alpha blocking effect that makes it useful as a local anesthetic and antiemetic

Question 6

cyproheptadine

Answer 6

• H1 antagonist and serotonin 5-ht2 antagonist
• used in carcinoid tumor
• Useful in limiting serotonin effects of bronchospasm and cold induced urticaria

Question 7

Second generation antihistamines-fexofenadine, loratadine, cetirizine

Answer 7

• less distribution into the CNS–>less sedation than 1st generation antihistamines
• metabolized by cyp3a4-c
• used for allergic rhinitis and chronic urticaria

Question 8

Bradykinin, kallidin

Answer 8

• ↑ IP3, DAG, cAMP, NO. Dilates arterioles, increases capillary permeability, stimulates sensory nerve endings
• kallidin is a precursor to bradykinin

Question 9

Short acting Glucocorticoids-hydrocortisone, prednisone, methylprednisolone

Answer 9

-Inhibition of phospholipase A2, reduces expression of
cyclooxygenase
-Treatment of severe refractory chronic asthma
-Oral, Duration: 12–24 h

Question 10

Intermediate-acting glucocorticoids-triamcinolone, betamethasone, dexamethasone

Answer 10

-Inhibition of phospholipase A2, reduces expression of
cyclooxygenase
-Give betamethasone to mother if delivery is expected before 34 weeks because it has increased transger across placenta as compared to cortisol

Question 11

Glucocorticoids available as an aerosol-beclomethasone, bedesonide, flunisolide, fluticasone

Answer 11

-MOA-Inhibition of phospholipase A2, reduces expression of cyclooxygenase
-Uses-Prophylaxis of asthma: drugs of choice
-Inhalation, Duration: 10–12 h
-Tox-Pharyngeal candidiasis, minimal systemic steroid
toxicity (eg, adrenal suppression)

Question 12

Mast cell degranulation inhibitors-cromolyn, nedocromil

Answer 12

-mainly for exercise induced asthma, chronic use may slightly reduce bronchial reactivity, NO effect on smooth muscle tone-do not reverse asthmatic bronchospasm, only for prophylactic use, can give to those w/ steroid phobia
-Reduce release of inflammatory and bronchoconstrictor mediators from sensitized mast cells
-Uses-Rarely used prophylaxis of asthma;
-cromolyn also used for ophthalmic, nasopharyngeal, and
gastrointestinal allergy
-Inhaled aerosol for asthma, cromolyn local application
for other applications, Duration: 3–6 h
-Tox-Cough

Question 13

Leukotriene pathway drugs-zileuton, montelukast, zafirlukast

Answer 13

• Principal advantage is that they’re taken orally and are therefore great for kids that poorly comply/no need to worry about growth restriction from steroids
• Pharmacologic antagonists at LTD4 receptors Inhibitor of lipoxygenase, reduces synthesis of leukotrienes
• Prophylaxis of asthma
• Oral Duration: 12–24 h
• Tox-Elevation of liver enzymes

Question 14

Omalizumab

Answer 14

-Binds IgE antibodies on mast cells; reduces reaction to
inhaled antigen
-Uses-Prophylaxis of severe, refractory asthma not
responsive to all other drugs
-Parenteral, administered as several courses of injections, Extremely expensive
-long-term toxicity not yet
well documented