Nursing Pharmacology Chapter 22: Serotonin Pharmacology
Buspirone (BuSpar): 5-HT1A agonist, a nonbenzodiazepine anxiolytic
Sumatriptan (Imitrex): 5-HT1D agonist: acute migraine and cluster headache.
Sumatriptan: (Imitrex)
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)
Generally mild
Altered sensations (tingling, warmth, etc.)
Dizziness
Muscle weakness
Neck pain
Chest pain (frequency: 5%)
In patients with ischemic heart disease
In patients with Prinzmetal's angina (variant angina)
Cyproheptadine (Periactin)
Ondansetron (Zofran)
Ketanserin
Granisetron (Kytril)
Ritanserin
Dolasetron
Tropisetron
Cyproheptadine (Periactin)
Overview
Blocks serotonergic and histaminergic affects on smooth muscle
No effect on histamine-stimulated gastric secretion
Significant antimuscarinic effects
Sedation
Reduces smooth muscle effects of carcinoid tumor
Reduces postgastrectomy dumping syndrome
Overview
Blocks 5-HT1c and 5-HT2 receptors (no activity another 5 HT or H1 histamine receptors
Blocks a1 adrenergic receptors
Blocks platelet 5-HT2 receptors (inhibits serotonin-mediated platelet aggregation)
Effective antihypertensive drug (probably acting through a1 adrenergic receptors
Blocks 5-HT2 receptors (no alpha blocking properties)
May alter platelet function
Ondansetron (Zofran)
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. -- major role in management of severe nausea and vomiting due to anticancer drugs
Clinical Use:
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 & 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 & vomiting
Side Effects:
Surgical patients:
3% increased liver transaminase enzyme levels
3% headache
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
Granisetron (Kytril)
More selective 5-HT3 receptor blocker compared to ondansetron
Clinical Use
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 may limit clinical use
Highly potent/selective 5-HT3 receptor blocker
Clinical Use:
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.