Severe lamotrigine toxicosis in a dog

Figures & data

Figure 1 Presenting electrocardiogram.

Notes: Six-lead electrocardiogram recording of a dog that was evaluated because of concern for ingestion of ~278 mg/kg (611.6 mg/lb) of lamotrigine. He was subsequently found to be neurologic with gastrointestinal signs. Note the multifocal ventricular tachycardia with a mean heart rate of 125 beats per minute. Paper speed =25 mm/s; 1 cm = 1 mV.

Table 1 Blood gas testing on day 1 and 2

Values	Day 1	Day 2	Reference values
pH	7.41	7.41	7.36–7.47
PCO2	28.6	27.4	30.0–50.0 mmHg
PO2	43.8	45.0	30.0–60.0 mmHg
HCT	42	40	40%–50%
SO2%	80.5	81.6	100%
Na^+	146.6	141.9	145.0–155.0 meq/L
K^+	3.7	4.6	3.6–4.9 meq/L
Cl^−	113.0	111.2	110.0–120.0 meq/L
Ca^++	1.36	1.37	1.15–1.35 mmol/L
Mg^++	0.5	0.4	0.1–1.5 mg/dL
Glucose	94	97	80–110 mg/dL
Lactate	0.9	1.7	0.5–2.5 mmol/L
BUN	12	10	5–30 mg/dL
Creatinine	1.1	1.3	0.7–1.8 mg/dL
TCO2	19.5	18.3	21–25 mmol/L
HCO3^−	18.7	17.5	18–26 mmol/L

Notes: Abbreviated blood gas panel results of the dog ingesting ~278 mg/kg (611.6 mg/lb) of lamotrigine. Blood gas panels taken on the first and second day of hospitalization.

Abbreviations: BUN, blood urea nitrogen; HCT, hematocrit.

Figure 2 Electrocardiogram taken on the second day of hospitalization.

Notes: Six-lead electrocardiogram recording obtained 24 h after the dog ingested ~278 mg/kg (611.6 mg/lb) of lamotrigine and was treated with intravenous fluids, lidocaine, and methocarbamol. At this time, there is a normal sinus rhythm with a mean heart rate of 114 beats per minute. Paper speed =50 mm/s; 1 cm = 1 mV.