Ondansetron - Zofran®

The authors make no claims of the accuracy of the information contained herein; and these suggested doses and/or guidelines are not a substitute for clinical judgment. Neither GlobalRPh Inc. nor any other party involved in the preparation of this document shall be liable for any special, consequential, or exemplary damages resulting in whole or part from any user's use of or reliance upon this material. PLEASE READ THE DISCLAIMER CAREFULLY BEFORE ACCESSING OR USING THIS SITE. BY ACCESSING OR USING THIS SITE, YOU AGREE TO BE BOUND BY THE TERMS AND CONDITIONS SET FORTH IN THE DISCLAIMER.

Usual Diluents

D5W, NS

Dilution Data

[All doses] [50 ml] [15 min]

Recent Update:
FDA Drug Safety Communication: New information regarding QT prolongation with ondansetron (Zofran):
https://www.fda.gov/Drugs/DrugSafety/ucm310190.htm

Safety Announcement

[06-29-2012] The U.S. Food and Drug Administration (FDA) is informing healthcare professionals and the public that preliminary results from a recently completed clinical study suggest that a 32 mg single intravenous dose of ondansetron (Zofran, ondansetron hydrochloride, and generics) may affect the electrical activity of the heart (QT interval prolongation), which could pre-dispose patients to develop an abnormal and potentially fatal heart rhythm known as Torsades de Pointes.

GlaxoSmithKline (GSK) has announced changes to the Zofran drug label to remove the 32 mg single intravenous dose. The updated label will state that ondansetron can continue to be used in adults and children with chemotherapy-induced nausea and vomiting at the lower intravenous dose recommended in the drug label, a dose of 0.15 mg/kg administered every 4 hours for three doses; however, no single intravenous dose should exceed 16 mg. Information from the new clinical study will be included in the updated drug label.

FDA will evaluate the final study results when available, and will work with GSK to explore an alternative single dose regimen that is both safe and effective for the prevention of chemotherapy-induced nausea and vomiting in adults.

The new information on QT prolongation does not change any of the recommended oral dosing regimens for ondansetron. It also does not change the recommended lower dose intravenous dosing of ondansetron to prevent post-operative nausea and vomiting.

As part of the ongoing safety review of ondansetron, FDA continues to assess data about the risk of QT prolongation and will update the public when more information becomes available. FDA previously issued a DSC about the ongoing safety review of ondansetron in September 2011.

----------------------------
Prevention of Nausea and Vomiting Associated with Initial and Repeat Courses of Emetogenic Chemotherapy
ZOFRAN Injection should be diluted in 50 mL of 5% Dextrose Injection or 0.9% Sodium Chloride Injection before administration.
Adults: The recommended adult intravenous dosage of ZOFRAN is three 0.15-mg/kg doses up to a maximum of 16 mg per dose. The first dose is infused over 15 minutes beginning 30 minutes before the start of emetogenic chemotherapy. Subsequent doses (0.15 mg/kg up to a maximum of 16 mg per dose) are administered 4 and 8 hours after the first dose of ZOFRAN.

Prevention of Postoperative Nausea and Vomiting
ZOFRAN Injection should not be mixed with solutions for which physical and chemical compatibility have not been established. In particular, this applies to alkaline solutions as a precipitate may form.

Adults: The recommended adult intravenous dosage of ZOFRAN is 4 mg undiluted administered intravenously in not less than 30 seconds, preferably over 2 to 5 minutes, immediately before induction of anesthesia, or postoperatively if the patient did not receive prophylactic antiemetics and experiences nausea and/or vomiting occurring within 2 hours after surgery. Alternatively, 4 mg undiluted may be administered intramuscularly as a single injection for adults. While recommended as a fixed dose for patients weighing more than 40 kg, few patients above 80 kg have been studied. In patients who do not achieve adequate control of postoperative nausea and vomiting following a single, prophylactic, preinduction, intravenous dose of ondansetron 4 mg, administration of a second intravenous dose of 4 mg ondansetron postoperatively does not provide additional control of nausea and vomiting.

Stability:
Ondansetron injection, USP is stable at room temperature under normal lighting conditions for 48 hours after dilution with the following I.V. fluids: 0.9% sodium chloride injection, 5 % dextrose injection, 5% dextrose and 0.9% sodium chloride injection, 5% dextrose and 0.45% sodium chloride injection, and 3% sodium chloride injection.

Although ondansetron injection, USP is chemically and physically stable when diluted as recommended, sterile precautions should be observed because diluents generally do not contain preservative. After dilution, do not use beyond 24 hours.

Precaution: Occasionally, ondansetron precipitates at the stopper/vial interface in vials stored upright. Potency and safety are not affected. If a precipitate is observed, resolubilize by shaking the vial vigorously.

STORAGE
Store vials between 20° and 25°C (68° and 77°F). Protect from light.

Stability / Miscellaneous

WARNINGS	CLINICAL PHARMACOLOGY	INDICATIONS
CONTRAINDICATIONS	DOSAGE AND ADMINISTRATION	RECONSTITUTION / DILUTION
	HOW SUPPLIED
Note: double mouse click to return to the top of the page

DESCRIPTION
The active ingredient in Ondansetron Injection, USP is the ondansetron hydrochloride (HCl), the racemic form of ondansetron and a selective blocking agent of the serotonin 5-HT3 receptor type.

The empirical formula is C18H19N3O - HCl - 2H2O, representing a molecular weight of 365.9. Ondansetron HCl is a white to off-white powder that is soluble in water and normal saline.

Sterile Injection for Intravenous (I.V.) or Intramuscular (I.M.) Administration: Each 1 mL of aqueous solution in the 2-mL single-dose vial contains 2 mg of ondansetron as the hydrochloride dihydrate; 9.0 mg of sodium chloride, USP, and 0.5 mg of citric acid monohydrate, USP and 0.25 mg of trisodium citrate dihydrate, USP as buffers in Water for Injection, USP.

Each 1 mL of aqueous solution in the 20-mL multidose vial contains 2 mg of ondansetron as the hydrochloride dihydrate; 8.3 mg of sodium chloride, USP; 0.5 mg of citric acid monohydrate, USP and 0.25 mg of trisodium citrate dihydrate, USP buffers; and 1.2 mg of methylparaben, NF and 0.15 mg of propylparaben, NF as preservatives in Water for Injection, USP.

Ondansetron Injection, USP is a clear, colorless, nonpyrogenic, sterile solution. The pH of the injection solution is 3.3 to 4.0.

CLINICAL PHARMACOLOGY

Pharmacodynamics:
Ondansetron is a selective 5-HT3 receptor antagonist. While ondansetron's mechanism of action has not been fully characterized, it is not a dopamine-receptor antagonist.

Serotonin receptors of the 5-HT3 type are present both peripherally on vagal nerve terminals and centrally in the chemoreceptor trigger zone of the area postrema. It is not certain whether ondansetron's antiemetic action in chemotherapy-induced nausea and vomiting is mediated centrally, peripherally, or in both sites. However, cytotoxic chemotherapy appears to be associated with release of serotonin from the enterochromaffin cells of the small intestine. In humans, urinary 5-HIAA (5-hydroxyindoleacetic acid) excretion increases after cisplatin administration in parallel with the onset of vomiting. The released serotonin may stimulate the vagal afferents through the 5-TH3 receptors and initiate the vomiting reflex.

In animals, the emetic response to cisplatin can be prevented by pretreatment with an inhibitor of serotonin synthesis, bilateral abdominal vagotomy and greater splanchnic nerve section, or pretreatment with a serotonin 5-HT3 receptor antagonist.

In normal volunteers, single I.V. doses of 0.15 mg/kg of ondansetron had no effect on esophageal motility, gastric motility, lower esophageal sphincter pressure, or small intestinal transit time. In another study in six normal male volunteers, a 16-mg dose infused over 5 minutes showed no effect of the drug on cardiac output, heart rate, stroke volume, blood pressure, or electrocardiogram (ECG).

Multiday administration of ondansetron has been shown to slow colonic transit in normal volunteers. Ondansetron has no effect on plasma prolactin concentrations.

In a gender-balanced pharmacodynamic study (n=56), ondansetron 4 mg administered intravenously or intramuscularly was dynamically similar in the prevention of nausea and vomiting using the ipecacuanha model of emesis.

Ondansetron does not alter the respiratory depressant effects produced by alfentanil or the degree of neuromuscular blockade produced by atracurium. Interactions with general or local anesthetics have not been studied.

INDICATIONS AND USAGE
1.] Prevention of nausea and vomiting associated with initial and repeat courses of emetogenic cancer chemotherapy, including high-dose cisplatin. Efficacy of the 32 mg single dose beyond 24 hours in these patients has not been established.

2.] Prevention of postoperative nausea and/or vomiting. As with other antiemetics, routine prophylaxis is not recommended for patients in whom there is little expectation that nausea and/or vomiting will occur postoperatively. In patients where nausea and/or vomiting must be avoided postoperatively, ondansetron injection, USP is recommended even where the incidence of postoperative nausea and/or vomiting is low. For patients who do not receive prophylactic ondansetron injection, USP and experience nausea and/or vomiting postoperatively, ondansetron injection, USP may be given to prevent further episodes (see PACKAGE INSERT FOR CLINICAL TRIALS).

CONTRAINDICATIONS
Ondansetron Injection, USP is contraindicated for patients known to have hypersensitivity to the drug.

WARNINGS
Hypersensitivity reactions have been reported in patients who have exhibited hypersensitivity to other selective 5-HT3 receptor antagonist.

DOSAGE AND ADMINISTRATION

Prevention of Nausea and Vomiting Associated with Initial and Repeat Courses of Emetogenic Chemotherapy
ZOFRAN Injection should be diluted in 50 mL of 5% Dextrose Injection or 0.9% Sodium Chloride Injection before administration.
Adults: The recommended adult intravenous dosage of ZOFRAN is three 0.15-mg/kg doses up to a maximum of 16 mg per dose. The first dose is infused over 15 minutes beginning 30 minutes before the start of emetogenic chemotherapy. Subsequent doses (0.15 mg/kg up to a maximum of 16 mg per dose) are administered 4 and 8 hours after the first dose of ZOFRAN.

Dosage Adjustment for Patients with Impaired Renal Function:
The dosage recommendation is the same as for the general population. There is no experience beyond the first-day administration of ondansetron.

Dosage Adjustment for Patients with Impaired Hepatic Function:
In patients with severe hepatic impairment (Child-Pugh2 score of 10 or greater), a single maximal daily dose of 8 mg to be infused over 15 minutes beginning 30 minutes before the start of the emetogenic chemotherapy is recommended. There is no experience beyond first-day administration of ondansetron.

Note: Parenteral drug products should be inspected visually for particulate matter and discoloration before administration whenever solution and container permit.

HOW SUPPLIED
ONDANSETRON INJECTION. USP, 2 mg/mL, is supplied as follows:

NDC 0143-9890-05 2-mL single-dose vials (Carton of 5)
NDC 0143-9890-01 20-mL multidose vial (Carton of 1)

STORAGE
Store between 20° and 25°C (68° and 77°F) [See USP Controlled Room Temperature]. Protect from light.

Reference(s)

[PACKAGE INSERT DATA] : ONDANSETRON (ondansetron hydrochloride) injection. WEST-WARD PHARMACEUTICAL Corp. 465 Industrial Way West. EATONTOWN NJ 07724. Rev.: Jan. 2009.

Other: Britto MR, Hussey EK, Mydlow P, et al. Effect of enzyme inducers on ondansetron (OND) metabolism in humans. Clin Pharmacol Ther. 1997;61:228. Pugh RNH, Murray-Lyon IM, Dawson JL, Pietroni MC, Williams R. Transection of the oesophagus for bleeding oesophageal varices. Brit J Surg. 1973;60:646-649. Villikka K, Kivisto KT, Neuvonen PJ. The effect of rifampin on the pharmacokinetics of oral and intravenous ondansetron. Clin Pharmacol Ther. 1999;65:377-381. De Witte JL. Schoenmaekers B, Sessler DI, et al. AnesthAnalg. 2001;92:1319-1321. Arcioni R, della Rocca M, RomanÒ R, et al. Anesth Analg. 2002;94:1553-1557