5-HT3 Receptor Antagonists include-
Alosetron, Dolasetron, Ondansetron, Palonosetron, Granisetron, Hydrolastron

Refer - 5-HT3 Receptor Antogonists

Dexamethasone enhances the effect of the drug.
Cisplatin, 5FU,carboplatin, etoposide, cyclophosphamide, ceftazidine, doxorubicin & dexamethasone
can be administered via the Y-site of infusion set. Dilution with normal saline,5% glucose
10% manitol I.V.infusion. Ringers I.V.infusion,potassium chloride 3% w/v with normal saline can also
 be done.

Prevention of nausea and vomiting associated with  cancer therapy.

INFORMATION UP DATE-

ONDANSETRON- RISKY IN QT PROLONGATION, CCF-

The antinausea drug ondansetron should not be used in patients with long QT syndome,
as they are at particular risk for developing Torsade de Pointes while taking the drug,
according to U.S. Food Drug Administration.

Also at risk are patients with congestive heart failure  or bradyarrhythmias, those predisposed
to  low potassium and magnesium levels, and those taking other drugs that can lead to
QT prologation.

Accodingly ECG monitoring is now recommended for such patients using ondanseteron. ( MIMS )  

Adverse reactions-

Ondansetron -Oral-

CNS -       Extrpyrimidal symptoms ( rare )

Hepatic -    AST  1%,   ALT 2%     ( exceed twice the upper limit )

Miscellaneous-  rash 1%,  anaphylaxis , angina, bronchospasm, ECG alterations,
                            grand mal seizures, hypokalemia,  vascular ocular events ( rare )

Dermatologic -   urticaria

Ophthalmic-      cases of transcient blindness, predominently administration reported

Ondansetron- Injection-

Cardiovascular -   angina ( chest pain ) ECG alterations, hypotension, tachcardia ( rare )

GI -                      Constipation 10%

Miscellaneous -  Rash 1%   hypkalemia ( rare )

5-HT3 Receptor Antagonists include-
Alosetron, Dolasetron, Ondansetron, Palonosetron, Granisetron, Hydrolastron

Refer - 5-HT3 Receptor Antogonists

Date of Approval-   February 1994

Indications:

Prevention of Nausea and vomiting associated with  cancer therapy.

Dosage: Injection
Recommended IV dose is  0.15mg/kg .The first dose is infused over  15 minutes
beginning 30 minutes before the start of the therapy. Subsequent doses are administered
4 and 8 hours after the first dose. Dilute in 50ml of  5% dextrose  injection or  0.9%
sodium chloride solution.

Dosage- Oral-
8mg orally 3 times a day
8mg orally administered 1 to 2 hours before radiotherapy, with subsequent doses every 8 hours
after the first dose for each day radiotherapy is given

Pharmacology:

Ondansteron is a selective 5-HT3 receptor antagonist, serotonin receptors are present both peripherally on the vagal nerve terminals and centrally in the CTZ of the area posterma. Ondansteron blocks serotonin 5-HT 3 receptors with little or no effect on dopamine receptors.

Unlike metoclopramide, ondansetron does not affect GI motility or lower esophageal sphincter tone.

Pharmacokinetics:

Following an oral dose of ondansetron peak plasma concentrations are acheived in approximately 1 - 1.5 hrs. Oral bioavailability in healthy volunteers has been reported as 59%.

The plasma clearance averages to 0.45 1/h/kg systemic clearance is markedly reduced with prolonged elimination half-life in patients with severe hepatic impairment.

Ondansetron is extensively metabolised with approximately 5% of a radiolabelled dose recovered as the parent compound from urine. The plasma protein binding is 470- 76% and the volume of distribution is 1.8 L/kg.

5-HT3 Receptor Antagonists include-
Alosetron, Dolasetron, Ondansetron, Palonosetron, Granisetron, Hydrolastron

Refer - 5-HT3 Receptor Antagonists

5-HT3 Receptor Antagonists include-
Alosetron, Dolasetron, Ondansetron, Palonosetron, Granisetron, Hydrolastron

Refer - 5-HT3 Receptor Antagonists