Antiemetic Drugs

• Particularly useful for patients undergoing these procedures, with a history of nausea, vomiting or motion sickness, or obese patients:  opthalmological surgery, laproscopic surgery or gynecologic procedures

• If not desirable for preanesthetic medication, drugs may be administered IV at the conclusion of surgery.

Some drug options

• Droperidol

  • Low doses; administered usually IV and prevents postoperative nausea/vomiting

  • Some reports: droperidol better than either metoclopramide or domperidone

  • Droperidol reported useful as antiemetic for patients having cesarean section using spinal anesthesia

  •  Low doses: not always effective but higher doses (at the end of surgery) may cause excessive recovery room sedation

•  Metoclopramide (Reglan)

  • Inconsistent, controversial for preoperative use

•  Ondansetron: (Zofran)

  • 5-HT₃ receptor antagonist (serotonin antagonist)

  • Administration: IV, 4-8 mg (adult) before induction: highly efficacious in preventing postoperative nausea/vomiting

  • Should be used selectively

  • Ondansetron 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 Dosage: 4-8 mg IV (administered over 2-5 minutes just before anesthesia induction) Highly effective in reducing postoperative nausea/vomiting incidents -- 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: effective both for prophylaxis and treatment of postoperative nausea/vomiting Decreases incidence and intensity of postoperative nausea and 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 for induction and maintenance of anesthesia may be as effective as ondansetron 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 Tropisetron: 5-HT3 receptor blocker Effective in managing symptoms induced by carcinoid syndrome-- also some gastrokinetic characteristics Effective in preventing chemotherapy/radiotherapy-induced emesis Effective in preventing postoperative nausea/vomiting when administered before general anesthetic induction Granisetron 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:  could limit clinical use Dolasetron: 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. Stoelting, R.K., "Renin, Plasma Kinins, and Serotonin", in Pharmacology and Physiology in Anesthetic Practice, Lippincott-Raven Publishers, 1999, pp 398-407

• Other drugs

  • Phenothiazines (e.g.,prochlorperazine); hydroxyzine;diphenidol