PHRM 111 Lecture Notes - Lecture 3: Hives, Orthostatic Hypotension, H1 Antagonist
Document Summary
Adrenergic receptor antagonist effects (inhibit baroreceptor reflex) Side effects : sedation, urinary retention*, blurred vision*, orthostatic hypotension. Itchy, raised wheals (edema of superficial skin), edema of subcutaneous tissues. H1 antagonists (1st line) 1st gen have faster onset, but 2nd gen is preferred. Chronic urticaria: daily dosing of 2nd gen h1s (less sedation), oral corticosteroid. Doxylamine and diphenhydramine are safe for pregnancy. Diphenhydramine is found in many otc sleep aids. Blockade of histamine and muscarinic receptors promotes sws (non-rem) But blockade of muscarinic receptors also inhibits rem sleep (anticholinergic) Local anesthesia diphenhydramine potent local anesthetic (more than procaine) Efficacy varies and can be diminished with continued use (switch types) Uses: allergic conditions (hay fever, allergic rhinitis, chronic urticaria) Recall: activation of h2 receptor on parietal cells promotes gastric acid release. Block direct stimulation of parietal cell by histamine. Use for treatment of duodenal and gastric ulcers (before ppis were developed) Block h3 receptors increase histamine levels in cns.
