Ondansetron (Zofran) is Superior to Metoclopramide (Reglan) for Preventing Chemotherapy-Induced Nausea and Vomiting in Older Patients
For older patients undergoing chemotherapy, ondansetron (Zofran) is more effective than metoclopramide (Reglan) for preventing chemotherapy-induced nausea and vomiting, with a better safety profile and fewer side effects.
Efficacy Comparison
5-HT3 receptor antagonists like ondansetron have demonstrated superior efficacy compared to dopamine receptor antagonists like metoclopramide in controlling chemotherapy-induced nausea and vomiting, particularly for moderate to highly emetogenic chemotherapy regimens 1
Ondansetron has been shown to be more effective than metoclopramide in patients receiving both high-dose and low-dose cisplatin treatment, as well as in non-cisplatin chemotherapy-induced emesis 2
In randomized trials, ondansetron was superior to metoclopramide and droperidol for prevention of chemotherapy-induced nausea and vomiting 1
Special Considerations for Older Patients
Elderly patients are especially sensitive to the extrapyramidal side effects and sedation that can occur with metoclopramide, making ondansetron a safer choice 3
Ondansetron has a more favorable side effect profile in older patients, with headache and constipation being the most common adverse events, compared to the more serious neurological side effects possible with metoclopramide 2
For elderly or over-sedated patients receiving ondansetron, a lower dose (5 mg) may be considered to minimize side effects while maintaining efficacy 1
Antiemetic Regimen Recommendations
For highly emetogenic chemotherapy in older patients, the NCCN guidelines recommend a 5-HT3 receptor antagonist (such as ondansetron) plus dexamethasone as the most efficacious and least toxic antiemetic therapy 1
For moderately emetogenic chemotherapy, a 5-HT3 receptor antagonist is indicated for patients who are refractory to corticosteroids or in those who cannot use them 4
For optimal control of both acute and delayed nausea and vomiting, ondansetron may be combined with dexamethasone, which has been shown to be significantly more effective than ondansetron monotherapy 2
Risk Factors and Monitoring
Being female, age less than 60 years, and receiving highly or moderately emetogenic chemotherapy are significant risk factors for chemotherapy-induced nausea and vomiting 5
Although older patients (>60 years) generally experience less nausea than younger patients, monitoring is still important, especially for delayed nausea which is often more severe and resistant to treatment 1
For patients with breakthrough emesis despite prophylaxis with ondansetron, consider adding other agents such as olanzapine, which acts on multiple receptor sites (dopaminergic, serotonergic, muscarinic, and histaminic) 1
Practical Administration Guidelines
For prevention of acute emesis, ondansetron should be administered before chemotherapy 1
In patients receiving multiday chemotherapy, ondansetron can be administered each day before the first dose of moderately or highly emetogenic chemotherapy 3
For anticipatory nausea and vomiting related to chemotherapy, consider combining ondansetron with benzodiazepines such as lorazepam or alprazolam 3, 1
Cautions and Contraindications
Perform a baseline ECG before initiating ondansetron treatment in older patients with cardiac risk factors due to potential QT prolongation 3
There is an increased risk of QT prolongation when ondansetron is administered with tyrosine kinase inhibitors, doxorubicin, serotonin reuptake inhibitors, and hydroxychloroquine 3
If ondansetron is not effective, DEX-sparing regimens incorporating palonosetron or multiple-day metoclopramide have been shown to be safe and at least as effective as standard treatment with a 3-day dexamethasone regimen with ondansetron 6