PRODUCT SYNOPSIS

Ondansetron, sold under the brand name TravelSet® Oral Spray, is an anti-emetic drug, belonging to the first-generation serotonin (5-hydroxytryptamine or 5-HT) receptor antagonist class.

PHARMACOLOGICAL ACTION

Ondansetron exhibits anti-emetic action by antagonising vomiting signals in the afferent pathway from the stomach or small intestine and solitary tract nucleus (a crucial brainstem region responsible for processing sensory information related to taste, visceral sensations, and certain autonomic functions, located in the medulla oblongata).²

Additional Pharmacological Effect: Ondansetron, being a selective serotonin 5-HT3 receptor antagonist, is effective in treating certain types of pruritus involving serotonin-related mechanisms, including uremic pruritus (since serotonin plays a role as a mediator of itching)._⁵

MECHANISM OF ACTION

• Ondansetron is a specific antagonist of serotonin type-3 receptors.
• To stop nausea and vomiting, Ondansetron works;
  1. centrally in the chemoreceptor trigger zone (postrema/NTS area) (near the medulla oblongata) and,
  2. peripherally at the vagal nerve terminals
• Ondansetron’s absence of antagonist activity on dopamine and other non-5-HT3 receptors indicates that, unlike other anti-emetics like metoclopramide, it doesn’t cause extrapyramidal or other dose-limiting side effects.³

BENEFITS

INDICATIONS

1. Nausea and vomiting induced by cancer chemotherapy, or anaesthesia and surgery.
2. Nausea/ vomiting associated with overdosage/poisoning of theophylline, paracetamol, colchicine or baclofen.
3. Gastrointestinal motility disorders (e.g., carcinoid syndrome, irritable bowel syndrome, diarrhea linked to diabetes or cryptosporidiosis, and chronic refractory diarrhea)
4. Vomitation sensation caused by specific pain or central nervous system disorders (e.g., alcohol (ethanol) dependence, opiate withdrawal, vertigo, cerebellar tremor, and psychosis related to Parkinson’s disease treatment).²
5. Seasickness (Typically experienced during boat or ship travel)⁴

CONTRAINDICATIONS

Not usually advised for children with gastroenteritis whose primary symptom is moderate to severe diarrhea because ondansetron’s most frequent adverse effect is diarrhea.⁶

Not recommended for cardiac patients due to the risk of QT prolongation (cardiac electrophysiological disorder).

SIDE EEFFECTS/ ADVERSE REACTIONS

Diarrhea, headache, fever, drowsiness, constipation, rash, blurred vision, and muscle spasm. Ondansetron is linked to lower sedation incidence compared to conventional antiemetics.

DRUG INTERACTIONS

No prominent drug interactions reported.

RECOMMENDED DOSAGE

The recommended dose of oral Ondansetron for Postoperative nausea and vomiting (PONV) prophylaxis is 4 or 8 mg. Meta-analysis suggests 8 mg as the optimal dose.
IV ondansetron 4 mg is generally used due to the lower body mass in Indian patients compared to their Western counterparts.³

ADMINISTRATION

Oral sprays of Ondansetron are administered by spraying directly into the mouth, which targets local or systemic absorption.

CONCLUDING REMARKS

Ondansetron is U.S. FDA-approved for preventing postoperative, chemotherapy-induced, and radiotherapy-induced nausea and vomiting.

Due to its higher efficacy and relatively lower adverse effect profile as compared to conventional antiemetic agents, this 5-HT3 receptor antagonist has become one of the agents of choice for controlling emesis. ¹

Travel Set Ondansetron Spray offers convenience in certain situations.

REFERENCES

1. Israili, Z. H. (2001). Clinical pharmacology of serotonin receptor type 3 (5-HT3) antagonists. Current Medicinal Chemistry – Central Nervous System Agents, 1(2), 171-199.
2. Pain Res Manag. 2006 Winter; 11(4): 245–247.
3. Eur J Cancer Clin Oncol. 1989:25 Suppl 1:S15-9.
4. Ondansetron. Drugs 52, 773–794 (1996).
5. Pain Res Manag. 2006 Winter; 11(4): 245–247.
6. Paediatr Child Health. 2011 Mar; 16(3): 177–179.

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