Early in my career, I encountered a patient with severe renal colic who also had a history of opioid use disorder, now with several years of sobriety. Our initial treatment options with the usual non-narcotic medications and IV fluids had offered some initial relief, but his pain had returned with a vengeance. His battle with opioids had been hard fought, and he was adamant that he would only resort to opioids if we had exhausted every other reasonable option.
As I scoured the literature along with my attending, looking for other viable options to get my patient some lasting relief, we found an interesting article about the use of IV lidocaine for the treatment of renal colic.
While there has yet to be a large multicenter RCT evaluating the efficacy of IV lidocaine specifically for renal colic, smaller retrospective studies have shown promise for this novel treatment option.
One single-center trial evaluated the effectiveness of IV lidocaine as an adjuvant to IV morphine, while another evaluated the effectiveness of IV lidocaine alone vs IV morphine. Both studies found statistically significant reductions in pain for patients with renal colic who received IV lidocaine, with the vast majority of patients reporting minimal or no side effects with no reported major adverse outcomes.
While the initial data for this treatment are promising in terms of safety and efficacy, not every patient with renal colic is a candidate for IV lidocaine. Contraindications to IV lidocaine include:
Allergies to lidocaine
Pregnancy
History of renal, hepatic, or cardiac disease
Age <18 or >65
In most studies, the usual dosage was 1.5 mg/kg infused via an IV pump over 10-30 minutes, with a maximum dosage of 200 mg. Patients were monitored for signs of CNS symptoms such as dizziness or confusion, as well as any adverse cardiac symptoms such as bradycardia, hypotension, or arrhythmias.
Pain relief was usually noted within 15-30 minutes of starting the infusion, and in some cases, patients remained pain-free for up to 24 hours after the infusion. Most studies did note that, given the limited data supporting the use of IV lidocaine, it should not be used as a first-line treatment for pain when other modalities such as NSAIDS or opioids are readily available and not contraindicated.
While IV Lidocaine may be a promising treatment option for renal colic, it is also a resource-intensive intervention. It is going to tie up a nurse and needs a monitored bed along with an infusion pump. This might not make it an ideal therapy in certain settings, like fast-tracks or triage-based treatment areas.
10 minutes into the infusion, my patient began to feel some relief. At 20 minutes, he was pain-free and remained that way until discharge. While IV lidocaine isn’t going to be an option for every patient presenting with renal colic, in the right patient population, it can be a great back-up option when other pain modalities just aren’t getting the job done.