Ondansetron Usage Before and After Sedation Appointment

A DOCS Education member asks:

Hi, my patient is a 24 year old woman who I have successfully treated with diazepam 10 mg HS and triazolam 0.5 mg prior to arrival and additional triazolam 0.25mg upon arrival. She has however experienced nausea in the past. We had to cancel one sedation appointment because she was not able to take additional medicine when she arrived.

She is only on birth control pills. She has a petite frame with little body fat. She is 5'5'' and probably 110 lbs.

At her last visit, we were able to accomplish endo on #30 and #12 DO restoration. The patient tolerated the procedure well from a clinical standpoint. At her post- op call, she said that she was more aware than she had been in the past. When asked if she felt she needed more medicine she said no because she was nauseous enough to ask her physician (without consult with me) to prescribe Ondansetron. She felt that that helped.

My questions are:

1 Would it be wise to prescribe the Ondansetron or some other anti-emetic PRIOR to treatment and if so at what dosage and when in relation to the Diazepam and or Triazolam dose?

1 a. The precautions listed with this medicine says that there is a contra-indication with epi. Should epi be avoided entirely if it is taken prior to treatment?

2. Should I plan of this patient using it after treatment?

Any other suggestions?


DOCS Education faculty member, Dr. Jerome Wellbrock, responds:

You mention your patient weighs approximately 110lbs. You need to know her exact weight so you can calculate her Top Dose of Triazolam. If she weighs 110 lbs then her Top Dose for triazolam would be 1.0 mg. You used 0.75 mg so you are nearing Top Dose. You may want to consider using hydroxyzine along with your triazolam protocol. It will help with the PONV. If you are going to use Ondansetron then it can be oral or IV. If you are using IV then I would administer towards the end of the sedation perhaps around 30 minutes prior to end of treatment. The IV dose would be 4 mg. If you are doing Oral Sedation only then I would dose the Ondansetron 1 hour prior to sedation as there is around a 30 minute onset time. The Oral Dose for Ondansetron can be up to 16mg. Ondansetron is supplied in either 4mg or 8 mg tablets. Zofran is expensive so definitely look for generic Ondansetron which should be available.

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