You see a patient who is diaphoretic, vomiting, and in obvious agony. STEMI? Dissection? Some other type of vascular catastrophe in progress? It very well could be, but if your clinical experience has been anything like mine, this kind of patient is much more likely to be passing a kidney stone. A good history and less than two minutes with a bedside ultrasound are usually all we need to confirm this diagnosis. Special thanks to Rebecca Smith-Bindman, MD, for driving this practice change. (N Engl J Med 2014;371:1100.)
Now the biggest question we face: How do we take this patient from miserable to manageable in the safest, shortest amount of time?
The good news is unlike many of the clinical questions we face on a daily basis (where we are forced to rely on anecdotal evidence and the signs read in sheep livers and chicken entrails), kidney stones are something that we have actually studied quite a bit. The bad news is these studies chose treatment agents we don't use anymore, with variations in dosage and how the medications were administered.
Let's start with our trusted friends at the Cochrane Review, who tackled the issue of opioids vs. NSAIDs in a review last updated in 2010. (Cochrane Database Syst Rev 2005;:CD004137.) They ended up analyzing 29 trials of 1,613 patients. The analysis was complicated by heterogeneity, but the results were clear: NSAIDs provided pain relief that was as good as if not slightly better than opioids with no difference in time to pain relief. Patients on NSAIDs also needed less rescue medication compared with opioids, and opioids caused significantly more vomiting.
Not convinced yet? Fair enough, but adding some weight to the Cochrane conclusions is a more recent systematic review by Pathan, et al. (Eur Urol 2017. doi: 10.1016/j.eururo.2017.11.001.) These analytic agitators examined 36 trials and 4,887 subjects, and included some trials that threw paracetamol into the mix. Once again, NSAIDs were found to provide pain relief that was at least equal to narcotics or acetaminophen, and they caused less vomiting (NNT=5). Those who took NSAIDs needed less rescue medication (NNT=11) than patients treated with opioids. (NSAIDs were also superior because those who took them needed fewer rescue meds when compared with those who took paracetamol. Unsurprisingly, there was no difference in the rates of vomiting between those two classes of medications.)
A word of caution about drawing conclusions from these systematic reviews: The opioid of choice in most studies was pethidine (better known as meperidine or the demon Demerol, use of which may have brought us duty-hour restrictions), and we don't use that medication much (read at all) anymore. Meperidine was known to cause more vomiting than your average opioid, but we all know that this is a common side effect of this medication class. The adverse event rate for current practice therefore might not be quite as dramatic as it was calculated to be in the Pathan review.
Setting Therapeutic Ceilings
So we have two reasonable (though not perfect) systematic reviews telling us to use NSAIDs before we move onto morphine, but what about the new kid on the block who is lighting up people's mentions and slipping into their DMs? I'm talking, of course, about IV lidocaine for renal colic, the best evidence for which comes from a 2012 paper by Soleimanpour, et al. (BMC Urol 2012;12:13. doi: 10.1186/1471-2490-12-13.)
They didn't bother to include our buddy ketorolac in this RCT of 240 patients. The too-long-didn't-read version holds that the data are underwhelming. Unless you believe anecdotes equal data, you might want to keep your powder dry on this one. An excellent deep dive on this topic from Rachel Littlefield, MD, and Tony Seupaul, MD, is in The Skeptics' Guide to Emergency Medicine. (Jan. 9, 2018; http://bit.ly/2CCG6m3.)
A word of apology concerning ketorolac dosing: We dosed Toradol in 30 mg and 60 mg aliquots during my residency days. It was a simpler time, when doctors just doctored, and if a few kidneys imploded along the way, well, that was just the price of doing business. We now live in an age where doctors try not to commit medical malpractice or don't want to cause harm by using unnecessarily high, ineffective medication doses.
Let's turn to the expert. The good Sergey Motov, MD, and company looked at optimal ketorolac dosing, and the take-home point was 10 mg of IV ketorolac gets the job done. (Ann Emerg Med 2017;70:177.)
Go big or go home is my mantra in the ED (and on Xbox Live), but it's probably bad medicine in this case. We have a nicely established therapeutic ceiling, and we should respect it, lest we nuke the kidney while treating the kidney stone.