Palonasentron (Aloxi) and (Ondanstetron) Zofran are drugs of the same class and are essentially interchangeable.In regard to the dosing of ondansetron, different statements are given by the NCCN than by the MASCC and ASCO. NCCN guidelines recommend ondansetron at a dose of 16–24 mg orally and 8–12 mg (maximum, 32 mg) i.v., whereas the MASCC and ASCO guidelines recommend ondansetron at a dose of 24 mg orally (MASCC, 16 mg orally for moderately emetogenic chemotherapy) and 8 mg or 0.15 mg/kg i.v. In a recently published meta-analysis comparing low-dose ondansetron (8 mg) with high-dose ondansetron (24 or 32 mg), in a subanalysis in cisplatin-based chemotherapy, high-dose ondansetron appeared to be more effective (p = .012)’
All three guidelines recommend palonosetron at a dose of 0.25 mg i.v. Palonosetron has a significantly longer half-life and a higher binding activity than the other 5-HT3RAs. The actual role of palonosetron in comparison with the other available 5-HT3RAs is discussed controversially in the guidelines. However, none of the three guidelines designates a preferred 5-HT3RA, although palonosetron outperformed ondansetron and dolasetron in some secondary endpoints in one study. NCCN MS-5 now says that palonasetron is preferred based on a meta-analysis. However, it still lists other options as well.
There is no reason to prefer one drug over another. However, in a situation where one drug appears to perform better, an exception to that charcterization is reasonable.
FDA notified healthcare professionals in 2011 that a contraindication is being added to the prescribing information advising that the injection form of Anzemet (dolasetron mesylate) should no longer be used to prevent nausea and vomiting associated with cancer chemotherapy (CINV) in pediatric and adult patients. New data demonstrate that Anzemet injection can increase the risk of developing torsade de pointes, an abnormal heart rhythm, which in some cases can be fatal. Patients at particular risk are those with underlying heart conditions or those who have existing heart rate or rhythm problems. Anzemet causes a dose-dependant prolongation in the QT, PR, and QRS intervals on an electrocardiogram.
Karin Jordan, Christoph Sippel, Hans-Joachim Schmoll Guidelines for Antiemetic Treatment of Chemotherapy-Induced Nausea and Vomiting: Past, Present, and Future Recommendations The Oncologist, Vol. 12, No. 9, 1143-1150, September 2007;
Hesketh PJ, Grunberg SM, Gralla RJ et al. The oral neurokinin-1 antagonist aprepitant for the prevention of chemotherapy-induced nausea and vomiting: A multinational, randomized, double-blind, placebo-controlled trial in patients receiving high-dose cisplatin—the Aprepitant Protocol 052 Study Group. J Clin Oncol 2003;21:4112–4119.
Schmoll HJ, Aapro MS, Poli-Bigelli S et al. Comparison of an aprepitant regimen with a multiple-day ondansetron regimen, both with dexamethasone, for antiemetic efficacy in high-dose cisplatin treatment. Ann Oncol 2006;17:1000–1006
Hauser JM, Kasi A. Antiemetic Medications. [Updated 2018 Nov 14]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019 Jan-.Available from: https://www.ncbi.nlm.nih.gov/books/NBK532303/