Page 311 - Basic _ Clinical Pharmacology ( PDFDrive )

CHAPTER 16 Histamine, Serotonin, & the Ergot Alkaloids 297

Mechanism Clinical Pharmacokinetics, Toxicities,
Subclass, Drug of Action Effects Applications Interactions
SEROTONIN BLOCKERS
5-HT 2 :
• Ketanserin (not Competitive Prevents vasoconstriction and Hypertension Oral • duration 12–24 h • Toxicity: Hypotension
available in USA) blockade at 5-HT 2 bronchospasm of carcinoid • carcinoid syndrome
receptors syndrome associated with
carcinoid tumor
5-HT 3 :
• Ondansetron, others (see Chapter 62)
ERGOT ALKALOIDS
Vasoselective:
• Ergotamine Mixed partial agonist Causes marked smooth muscle Migraine and cluster Oral, parenteral • duration 12–24 h • Toxicity:
effects at 5-HT 2 and contraction but blocks headache Prolonged vasospasm causing angina,
α adrenoceptors α-agonist vasoconstriction gangrene; uterine spasm
Uteroselective:
• Ergonovine Mixed partial agonist Same as ergotamine • some Postpartum bleeding Oral, parenteral (methylergonovine) • duration
effects at 5-HT 2 and selectivity for uterine smooth • migraine headache 2–4 h • Toxicity: Same as ergotamine
α adrenoceptors muscle

CNS selective:
• Lysergic acid Central nervous Hallucinations None • widely Oral • duration several hours • Toxicity:
diethylamide system 5-HT 2 and • psychotomimetic abused Prolonged psychotic state, flashbacks
dopamine agonist
• 5-HT 2 antagonist in
periphery
• Bromocriptine, pergolide: Ergot derivatives used in Parkinson’s disease (see Chapter 28) and prolactinoma (see Chapter 37). Pergolide used in equine
Cushing’s disease

PREP AR A TIONS A V AIL ABLE

GENERIC NAME AVAILABLE AS GENERIC NAME AVAILABLE AS
ANTIHISTAMINES (H 1 BLOCKERS) * Fexofenadine Generic, Allegra
Azelastine Generic, Astelin (nasal), Optivar
(ophthalmic) Hydroxyzine Generic, Vistaril
Brompheniramine Brovex, Dimetapp, others Ketotifen Generic, Zaditor
Buclizine Bucladin-S Softabs Levocabastine Livostin
Levocetirizine Generic, Xyzal
Carbinoxamine Generic, Histex
Loratadine Generic, Claritin
Cetirizine Generic, Zyrtec
Meclizine Generic, Antivert, Bonine
Chlorpheniramine Generic, Chlor-Trimeton
Clemastine Generic, Tavist Olopatadine Patanol, Pataday
Cyclizine Generic, Marezine Phenindamine Nolahist
Cyproheptadine Generic, Periactin Promethazine Generic, Phenergan
Desloratadine Generic, Clarinex Triprolidine Generic, Zymine, Tripohist
Dimenhydrinate † Generic, Dramamine H 2 BLOCKERS
Diphenhydramine Generic, Benadryl See Chapter 62.
Doxylamine Diclegis (combination with 5-HT AGONISTS
pyridoxine), Unisom Sleep Tabs Almotriptan Axert
Epinastine Generic, Elestat Eletriptan Relpax
(continued)