Disulfiram-ethanol Reaction Linked to the Consumption of Fermented Pickles: A Unique Case Encounter

Disulfiram irreversibly inhibits aldehyde dehydrogenase (ALDH), a key liver enzyme responsible for oxidizing acetaldehyde to acetate, resulting in acetaldehyde accumulation. It is commonly used in the treatment of alcohol dependence. Upon ethanol ingestion, ALDH inhibition leads to a buildup of acetaldehyde in the blood, and it produces an unpleasant physiological reaction known as the disulfiram-ethanol reaction (DER). ¹ DER can cause flushing, diaphoresis, nausea, vomiting, vertigo, tachycardia, hypotension and, in severe cases, cardiovascular collapse. ¹

Patients are routinely counseled to avoid alcoholic beverages, less emphasis is often placed on avoiding food products that may contain trace amounts of ethanol, such as vinegar, kimchi, kombucha, sauces, and fermented pickles.^1,2 Even a small amount of alcohol can cause DER. Pandey and Garg (2023) reported a DER by vinegar-containing noodles, highlighting a rare case of DER from a non-beverage source of alcohol. ³ Similarly, literature has described DER following ethanol exposure from hand sanitizer.^4,5 This recent documentation highlights the need to increase awareness about hidden ethanol sources, which are often regular dietary components. The treating team frequently overlooks these sources, risking complications such as DER. Here, we report a novel case of DER in an alcohol-dependent patient triggered after fermented pickle consumption. We have obtained written informed consent for this publication.

Case Report

A 46-year-old married man with a 20-year history of alcohol and nicotine dependence was admitted to the psychiatry inpatient department for treatment of alcohol dependence. After managing withdrawal symptoms with lorazepam, it was gradually tapered off. The disulfiram 250 mg once daily was started after obtaining written informed consent. The patient was educated about the risks and symptoms of DER and possible substances to be avoided besides alcohol.

On the second day of disulfiram, the patient developed acute symptoms, including facial flushing, sweating, restlessness, tachycardia, and palpitations. His father always accompanied him during his hospital stay, and his father denied any alcohol intake by the patient. A detailed history revealed that the patient had consumed fermented pickles with food about 1–2 hours before the onset of symptoms. Owing to the unavailability of testing kits, we were unable to objectively confirm alcohol exposure through breath analysis or biomarker assessment in urine or blood. A DER was suspected, given the clinical picture and temporal association of symptoms. Disulfiram was immediately discontinued, and the patient was managed conservatively. His routine electrocardiogram and vital monitoring were uneventful, other than tachycardia. Symptoms subsided within a few hours. The patient and family were psycho-educated about avoiding all forms of ethanol, including vinegar, fermented pickles, sauces, and over-the-counter preparations. The patient refused the disulfiram rechallenge and was instead initiated on tab baclofen 20 mg/day. He was also educated on identifying triggers and building effective coping strategies. He was discharged in stable condition.

Discussion

This case describes a classic DER triggered by trace ethanol in fermented pickles. The possible explanation for DER here involves three interrelated factors: trace ethanol exposure from fermented food, genetic predisposition, particularly ALDH2 polymorphism, and disulfiram pharmacodynamics. Disulfiram irreversibly inhibits the ALDH enzyme, accumulating acetaldehyde even with small amounts of ethanol, which can trigger DER. ¹ DER can be triggered by ethanol doses as low as 5–10 mg, especially in sensitized individuals. The effects of disulfiram persist up to 14 days post-dose. ⁶ Therefore, patients remain at risk of DER from both alcoholic beverages and hidden or non-beverage ethanol sources. Fermented food products naturally contain ethanol, depending upon the fermentation process, storage temperature, and microbial profile. ⁷ So, these trace ethanol levels can trigger DER when consuming sufficient quantities or in individuals with heightened sensitivity. Given the patient’s 10-day alcohol abstinence, it is highly plausible that trace ethanol in the fermented pickle triggered a significant DER.

Genetic variants such as ALDH2*2 are prevalent in East Asian populations. ⁸ This polymorphism reduces ALDH activity, significantly impairing ethanol metabolism. When combined with pharmacologic inhibition (disulfiram), such patients experience an exponentially higher risk of DER. ⁹ Additionally, polymorphisms in dopamine β-hydroxylase and cytochrome P450 enzymes may affect both disulfiram metabolism and neurological sensitivity to acetaldehyde, further increasing the individual risk of DER. ¹⁰ Literature highlights that even minimal ethanol exposure, such as from vinegar-laced food, caused short-lasting non-malignant skin reactions with disulfiram. ³ Other studies and case reports documented DERs and isopropanol toxicity from ethanol-based hand sanitizers.^4,5 The index case supports these findings by reporting pickle-induced DER. The Naranjo Probability score for this patient was six, indicating “probable causality.” ¹¹

Conclusions

Psychiatric and pharmacologic literature caution against vinegar, sauces, and other fermented products during disulfiram therapy. However, these warnings are often overlooked in institutional settings such as hospitals, where food services may be unaware of dietary restrictions. Effective liaising between clinical and dietary departments is essential to discuss the importance of extending dietary precautions beyond obvious alcohol sources. All this can further facilitate the development of institutional protocols to identify and eliminate ethanol-containing ingredients in food served to patients on disulfiram.

Supplemental Material

Supplemental material for this article available online.