In this episode, I’ll discuss the discrepancy between the labeled dose and the analgesic ceiling dose of IV ketorolac.
Shout out to “Pharmacy Kelsey” for inspiring this episode!
If ketorolac is 100% bioavailable, why is the oral maximum daily dose 40 mg while the IV maximum daily dose is 120 mg?
How this came to be is a mystery to me.
The analgesic ceiling dose of ketorolac is 10 mg, and this was well-established in several articles over 20 years ago.
In 1989, a study in the Journal of Clinical Pharmacology compared 10, 30, and 90 mg of IM ketorolac with placebo in 126 patients with cancer pain. While all doses were more effective than placebo, there was no difference in effectiveness between 10, 30, or 90 mg of IM ketorolac.
In 1990, a study in Pharmacotherapy compared 2 or 4 mg IV morphine with 10 or 30 mg IV ketorolac in 122 patients who had undergone major surgery. Both doses of ketorolac were as effective as 4 mg morphine and more effective than 2 mg morphine in providing pain control. There was no difference in efficacy between 10 and 30 mg of ketorolac.
More recently, a trial by Sergey Motov confirmed this data by demonstrating IV ketorolac has an analgesic ceiling dose of 10 mg in ED patients with moderate to severe acute pain.
This data, together with the dose-related risk of GI bleeding from ketorolac documented in the prescribing information, has caused me to abandon using the 30 and 60 mg doses of ketorolac in my practice.
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