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Dimenhydrinate in Elderly

Question# 730

Once Zonfran have been given to someone who is over 65 and it is not relieving the N/V after 30 mins, would it be appropriate to give 25mg of Gravol at this point even though they are over the age of 65? I understand why we do not want to give it right away. Thank you, I look forward to hearing from you soon.


Hello and thank you for your MedicASK regarding the administration of Dimenhydrinate post Ondansetron, in the elderly population.

As you are aware, the ALS PCS nausea/vomiting medical directive does state, "If a patient has received Ondansetron and has no relief of their nausea & vomiting symptoms after 30 minutes, Dimenhydrinate may be considered (or vice versa)."

However, as your question is specific to those greater or equal to 65 years of age, and the administration of Dimenhydrinate is a contraindication (unless Ondansetron is not available), a patch is required as it is a deviation from the medical directive.

You are also correct in that a dose of 25mg of Dimenhydrinate would be more appropriate due to its side effects on this patient population.

Hope this helps. Please reach out should you have any additional questions or concerns!


ALS PCS nausea/vomiting medical directive

Medical Directive Category



30 August 2023

ALSPCS Version




Please reference the MOST RECENT ALS PCS for updates and changes to these directives.