Medical Pharmacology Chapter 22: Serotonin Pharmacology
Buspirone (BuSpar)-- 5-HT1A agonist, a nonbenzodiazepine anxiolytic
Relief of migraine symptoms for most patients.
Efficacy greater than or equal to other drug treatments (including parenteral agents or oral ergot alkaloids).
Multiple dosing may be required (headache lasts longer than single dose duration).
Altered sensations (tingling, warmth, etc.).
Chest pain (frequency: 5%).
In patients with ischemic heart disease.
In patients with Prinzmetal's angina (variant angina).
Blocks serotonergic and histaminergic affects on smooth muscle
No effect on histamine-stimulated gastric secretion
Significant antimuscarinic effects
Reduces smooth muscle effects of carcinoid tumor.
Reduces postgastrectomy dumping syndrome.
Blocks 5-HT1c and 5-HT2 receptors (no apparent activity on other 5 HT or H1 histamine receptors)
Blocks α1 adrenergic receptors
Blocks platelet 5-HT2 receptors (inhibits serotonin-mediated platelet aggregation).
Effective antihypertensive drug (probably acting through α1 adrenergic receptors.
Blocks 5-HT2 receptors (no alpha blocking properties).
May alter platelet function.
5-HT3 receptor blocker
Minimal effects on dopamine, histamine, adrenergic or cholinergic receptor activity
Very effective for prevention of nausea and vomiting caused by chemotherapy or surgery.
This agent has a major role in management of severe nausea and vomiting due to anticancer drugs
Dosage: 4-8 mg IV (administered over 2-5 minutes just before anesthesia induction).
Highly effective in reducing postoperative nausea/vomiting incidence -- particularly in susceptible patient groups:
Ambulatory gynecologic surgery.
Middle ear surgery.
Oral or IV reduces incidence of postoperative vomiting and preadolescent children undergoing:
Ambulatory surgery, e.g. tonsillectomy, strabismus surgery.
Ondansetron (Zofran): effective both for prophylaxis and treatment of postoperative nausea/vomiting.
Decreases incidents and intensity of postoperative nausea & vomiting -- but does not totally eliminate this problem.
Major advance: reduced side effects compared to previously used antiemetic drugs such as:
Phenothiazines, antihistamines, butyrophenones.
Propofol (Diprivan) for induction and maintenance of anesthesia may be as effective as ondansetron (Zofran) in reducing/preventing postoperative nausea and vomiting.
3% increased liver transaminase enzyme levels.
No sedation, hypotension, dysphoria, extrapyramidal reactions -- side effects associated with other antiemetic drugs.
5-HT3 receptor blocker.
Effective in managing symptoms induced by carcinoid syndrome-- also some gastrokinetic characteristics.
Effective in preventing chemotherapy/radio therapy-induced emesis.
Effective in preventing postoperative nausea/vomiting when administered before general anesthetic induction.
More selective 5-HT3 receptor blocker compared to ondansetron.
Effective in the chemotherapy-induced emesis prevention.
Effective in preventing postoperative nausea/vomiting.
Elimination half-life: nine hours, compared to about three hours for ondansetron: suggesting less frequent dosing with granisetron.
Significantly higher cost-- could limit clinical use
Highly potent/selective 5-HT3 receptor blocker.
Effective in preventing chemotherapy-induced nausea/vomiting.
Effective in reducing likelihood of postoperative nausea & vomiting.
Antiemetic effect due to long-acting, active metabolite (hydrodolasetron; elimination half-life = approximately 8 hours).
Burkhalter, A, Julius, D.J. and Katzung, B. Histamine, Serotonin and the Ergot Alkaloids (Section IV. Drugs with Important Actions on Smooth Muscle), in Basic and Clinical Pharmacology, (Katzung, B. G., ed) Appleton-Lange, 1998, pp 261-286.