Summary

Quinidine is one of the oldest antiarrhythmics known. Over the years, its use has decreased along with its side effects. Our case describes a 69-year-old woman with recurrent resistant ventricular tachycardia on quinidine and amiodarone who presented with acute liver toxicity. Drug-induced liver toxicity was at the top of our differential diagnosis list. Taking multiple factors into consideration, a decision was made to discontinue quinidine, the patient’s symptoms and lab abnormalities resolved within 1 week, yielding the diagnosis of quinidine hypersensitivity.

Background

Quinidine is a natural cinchona alkaloid with potent antiarrhythmic activity. It was Food and Drug Administration approved in 1950 to treat atrial and ventricular arrhythmias. Many studies have shown that treatment with quinidine increases mortality, therefore its use has declined significantly as well as the rate of its side effects.1 The most frequently described side effects are gastrointestinal, including nausea, diarrhoea, abdominal bloating and discomfort.2 Quinidine hypersensitivity is another side effect that occurs in up to 2% of treated patients and can present with fever, mild jaundice and an apparent liver injury.1 Hypersensitivity is well described in the literature, most of these cases were reported from the 1970s and 1980s when quinidine’s use was prevalent.

Patients with complicated medical comorbidities are often placed on multiple medications with overlapping side effects. In the setting of …