Histamine and Inflammation drugs Flashcards
H1 receptor antagonist
Class: ___
Mech: H1 receptor antagonist; rapidly absorbed orally, widely distributed, rapidly metabolized via liver microsomes
Thera: Allergic reactions (rhinitis, urticaria, conjunctivitis), motion sickness, nausea and vomiting in pregnancy, sleep aids
Important SE’s: Sedation, anti-muscarinic action, poisoning (especially children) with convulsions, allergy, local anesthesia (has actions not ascribable to H1 blockade because of muscarinic cholinoceptor, a-adrenoceptor, serotonin, local anesthetic receptor sites)
Misc: Older agents cross CNS to cause central effects
Diphenhydramine (Benadryl)
Class: Ether/ethanolamine derivitive
Mech: H1 receptor antagonist
Important SE’s: Anti-muscarinic, sedating
Tripelennamine (Pyribenzamine)
Class: Ethylenediamine derivitive
Mech: H1 receptor antagonist
Thera: OTC sleep aid; moderate sedation
Meclizine (Marezine)
Class: Piperazine derivative
Mech: H1 receptor antagonist
Thera: Motion sickness
Promethazine (Phenergan)
Class: Phenothiazine derivative
Mech: H1 receptor antagonist
Thera: Antiemetic
Important SE’s: Anti-muscarinic, sedating (because of cholinergic receptors, dry mouth, urinary retention, sinus tachy; because of alpha-adre, hypotension, dizziness, reflex tachy)
Chlorpheniramine (Chlor-Trimeton)
Class: Alkylamine derivitive
Mech: H1 receptor antagonist
Thera: Component of “cold” medications
Important SE’s: Less sedating
Loratadine (Claritin)
Class: Piperidine derivitive
Mech: 2nd generation H1 receptor antagonist
Thera: Allergic rhinitis
Important SE’s: No sedation
Other SE’s: Cardiovascular effects (rare, with high doses)
Misc: Poorly crosses BBB, so fewer central and side effects; once daily dosing
Fexofenadine (Allegra)
Class: Piperidine derivitive
Mech: 2nd generation H1 receptor antagonist
Thera: Allergic rhinitis
Important SE’s: No sedation
Other SE’s: Cardiovascular effects (rare, with high doses)
Misc: Poorly crosses BBB, so fewer central and side effects; once daily dosing
Azelastine (Astelin)
Mech: 2nd generation H1 receptor antagonist
Thera: Allergic rhinitis (intranasal spray), allergic conjunctivitis (ophthalmic solution)
Important SE’s: No sedation
Misc: Poorly crosses BBB, so fewer central and side effects
Cetirizine (Zyrtec)
Mech: 2nd generation H1 receptor antagonist
Thera: Allergic rhinitis
Important SE’s: No sedation
Misc: Poorly crosses BBB, so fewer central and side effects
Cimetidine (Tagamet)
Mech: H2 receptor antagonist; blocks gastric acid secretion (more so with nocturnal acid secretion than meal secretion)
Thera: Dyspepsia, duodenal and gastric ulcers, hypersecretory conditions
Important SE’s: Antiandrogen (causing impotence and gynecomastia), inhibition of P450 enzymes
Other SE’s: CNS dysfunction possible
Misc: Most side effects of H2-blocker class
Ranitidine (Zantac): how different from cimetidine?
Important SE’s: Liver toxicity
Famotidine (Pepcid): how different from cimetidine?
No Important SE’s or misc
Nizatidine (Axid): how different from cimetidine?
Misc: Least side effects of H2-blocker class
Cyproheptadine (Periactin)
Mech: Antihistaminic and antiserotinergic
Thera: Skin allergies (urticaria, anti-5HT1), diarrhea of carcinoid syndrome (anti-5HT2)
Other SE’s: Sedation, antimuscarinic
Ketanserin
Mech: Selective 5HT2A,2C receptor antagonist, as well as α1 and H1 receptor antagonist
Thera: Antihypertensive (relaxes vascular and tracheal smooth muscle), antiplatelet aggregation
Odansetron (Zofran)
Mech: 5HT3 receptor antagonist
Thera: Nausea and vomiting in chemotherapy
Ergot alkaloids
Mech: Agonist and antagonist actions at 5HT and α-adrenergic receptors
Important SE’s: Powerful hallucinations, smooth muscle contraction (vascular and uterine, latter leading to abortion)
Ergotamine (Ergomar)
Class: Ergot alkaloid
Mech: Nonspecific partial agonist at all 5HT1,2 receptors; partial agonist at α-adrenergic receptors
Thera: Prodrome of migraines
Other SE’s: N/V, cumulative and prolonged vasoconstriction
Methysergide (Cycloset)
Class: Ergot alkaloid
Mech: Partial agonist at all 5HT1 receptors, antagonist at 5HT2
Thera: Prophylaxis of migraines
Other SE’s: GI disturbances, inflammatory fibrosis (chronic use), hallucinations
Misc: Withdrawn from U.S. market
Ergonovine
Class: Ergot alkaloid
Thera: Postpartum hemorrhage (Oxytocic)