ATC codes: A04AA01
Nausea or vomiting ICD11 code: MG10
Medicine type
Chemical agent
List type
Parenteral > General injections > IV: 2 mg per mL in 2 mL ampoule (ondansetron base, as hydrochloride)
Oral > Liquid: 4 mg per 5 mL (ondansetron base)
Oral > Solid: 4 mg (ondansetron base) ; 8 mg (ondansetron base) ; 24 mg (ondansetron base) (EML)
EML status history
First added in 2009 (TRS 958)
Changed in 2019 (TRS 1021)
Also recommended for children
Age restriction
> 1 month
Therapeutic alternatives
Medicines within the same pharmacological class can be used
Patent information
Patents have expired in most jurisdictions
Expert Committee recommendation
The Committee recommended the addition of a square box to the listing of ondansetron on the EML and EMLc, noting that the original recommendation to list ondansetron in 2009 had included a square box.
Ondansetron was first included on the EML and EMLc following a review of antiemetic medicines considered by the 2009 Expert Committee (1). Listing was recommended with a square box symbol, designating ondansetron as representative of the pharmacological class of 5-HT3 receptor antagonists. However, the square box was inadvertently omitted when the lists were published. Alternative 5-HT3 receptor antagonists within the pharmacological class are shown below: A04AA01 Ondansetron A04AA02 Granisetron A04AA03 Tropisetron A04AA04 Dolasetron A04AA05 Palonosetron
Additional evidence
A 2016 systematic review of 299 studies (58 412 patients) identified during the application review process investigated the comparative safety and effectiveness of 5-HT3 receptor antagonists in patients undergoing chemotherapy. The review concluded that most 5-HT3 receptor antagonists used alone, or in combination with corticosteroids, were effective at decreasing the occurrence of nausea and/or vomiting, and were similarly safe when compared to each other (2).
Cost / cost effectiveness
The square box indicating therapeutic equivalence between alternative 5-HT3 receptor antagonists will allow tendering among available options or competition in pooled procurement mechanisms at country/local level or benchmarking for lowering prices.
WHO guidelines
None available.
The 5-HT3 receptor antagonists have wide market availability and are available in generic forms.
Other considerations
Comments on the application were received from the WHO Department of Management of NCDs, Disability, Violence and Injury Prevention. The technical unit advised that it supported the addition of a square box to the listings of ondansetron as representative of the pharmacological class of 5-HT3 receptor antagonists, stating that this class of medicines are essential medicines for the optimal management of common treatment-related adverse events associated with emetogenic chemotherapy.
1. The selection and use of essential medicines. Report of the WHO Expert Committee, 2009 (including the 16th WHO Model List of Essential Medicines and the 2nd WHO Model List of Essential Medicines for Children) (WHO Technical Report Series, No. 958). Geneva: World Health Organization; 2009. Available from https://apps.who.int/iris/bitstream/handle/10665/44287/WHO_TRS_958_eng.pdf, accessed 30 October 2019. 2. Tricco AC, Blondal E, Veroniki AA, Soobiah C, Vafaei A, Ivory J et al. Comparative safety and effectiveness of serotonin receptor antagonists in patients undergoing chemotherapy: a systematic review and network meta-analysis. BMC Med. 2016;14(1):216.