Lamotrigine Toxicosis Treated with Intravenous Lipid Emulsion Therapy in a Dog

Abstract

A female spayed dachshund/mixed-breed dog was evaluated following ingestion of lamotrigine tablets with subsequent rapid onset of vomiting, diarrhea, and generalized tremoring. On initial examination, the dog was moderately obtunded and nonambulatory with intermittent myoclonus and hyperesthesia. Electrocardiogram revealed sinus tachycardia with prolongation of the QT interval. Intravenous lipid emulsion (ILE) infusion was initiated, with reduction in tremoring and improved patient mentation being noted after ∼20 min of therapy. An elevated cardiac troponin I value measured at 1.02 ng/mL the day after presentation. Serum toxicological assay revealed marked reduction in serum lamotrigine levels following ILE and continued reduction during hospitalization. The dog’s clinical signs resolved, corrected QT interval returned to normal, and the patient was discharged 38 hr after presentation. Individual cases of lamotrigine toxicosis have not been fully reported in veterinary literature. This case report documents the rapid onset of clinical signs including neurologic dysfunction, cardiac arrhythmias, and transient corrected QT prolongation. Serial serum concentrations of lamotrigine showed a rapid reduction with ILE therapy and corresponded with clinical recovery, suggesting efficacy of ILE treatment in this case.

Successful management of massive lamotrigine extended‐release intoxication in a dog

“…This is a commonly encountered issue with toxin ingestion. At the time the case was being managed, we felt the benefit of IVLE administration outweighed the risk of therapeutic drug attenuation in this patient, given previous documentation of favorable outcomes 15‐19 . Further studies are needed to determine the efficacy of IVLE administration in LTG XR intoxication.…”

“…A more recent case report documented a 1‐year‐old dachshund/mixed breed dog who ingested LTG 135–162 mg/kg and displayed neurologic and cardiovascular effects that also responded well to IVLE. Additionally, IVLE therapy led to a significant decrease in measured serum lamotrigine levels 17 …”

“…While it might not have changed the treatment, evaluation of LTG presence in the serum was not available. Serum LTG may have allowed us to serially monitor response to IVLE treatment as previously described 17 …”

“…Once the intoxicant was identified as LTG XR, a more targeted therapeutic approach was performed. An infusion of intralipids has previously been shown to be successful in other cases of LTG toxicosis in both dogs and humans due to the lipid‐soluble nature of LTG 13,16‐19 26 .…”

“…Previous case reports of LTG intoxication have been reported in dogs, ranging from 26 to 278 mg/kg 15‐17 . Adverse effects documented included ventricular arrythmias, neurologic abnormalities (including nystagmus and extensor rigidity), and all 3 of the dogs returned to normal between 24 and 72 h. Infusion of intralipids have been found to be beneficial in treatment of LTG intoxication in humans and dogs due to the lipid‐soluble nature of the drug 13,16‐19 …”