Disulfiram, sold under the brand name Antabuse, produces side effects that range from mild daily nuisances like drowsiness and a metallic taste to rare but serious complications involving the liver, nervous system, and heart. The drug’s most dramatic effects, however, are deliberately triggered: disulfiram is designed to make drinking alcohol extremely unpleasant, and the resulting “disulfiram-ethanol reaction” accounts for many of the worst experiences patients report. Understanding which side effects are expected features of the drug’s design and which are genuine warning signs can make the difference between a manageable treatment course and a medical emergency.
How Disulfiram Works and Why That Matters for Side Effects
When you drink alcohol, your body breaks it down in two steps. First, an enzyme converts ethanol into acetaldehyde, a toxic intermediate. Normally, a second enzyme called aldehyde dehydrogenase quickly converts that acetaldehyde into harmless acetic acid. Disulfiram blocks that second enzyme, so acetaldehyde builds up in your blood instead of being cleared.1PubMed Central. Disulfiram: Mechanisms, Applications, and Challenges That buildup is what makes you feel terrible if you drink while taking the medication, and it’s the whole point of the drug: the experience is supposed to be bad enough that you don’t want to drink again.
But the same enzyme-blocking action that makes disulfiram effective against alcohol also affects other metabolic pathways in the body. Disulfiram and its breakdown products interfere with several enzyme systems beyond aldehyde dehydrogenase, and those broader effects are what produce the side effects that show up even when you haven’t touched a drop of alcohol.
The Disulfiram-Ethanol Reaction
If you drink any amount of alcohol while disulfiram is in your system, the reaction typically starts within minutes. The classic symptoms are flushing of the face and neck, a throbbing headache, nausea, vomiting, sweating, and shortness of breath. Most of the time these symptoms are self-limiting, meaning they fade on their own as the alcohol and acetaldehyde clear.2PubMed. Refractive hypotension in a patient with disulfiram-ethanol reaction The intensity depends largely on how much alcohol you consumed: a sip of wine produces a milder version than several drinks.
In severe cases, the reaction can become dangerous. Blood pressure may drop sharply, sometimes to the point of refractory hypotension that resists standard treatment.3PubMed. Refractive hypotension in a patient with disulfiram-ethanol reaction More severe reactions can include irregular heart rhythms, heart attack, acute heart failure, seizures, loss of consciousness, and, rarely, death. Because of these cardiovascular dangers, disulfiram is generally considered off-limits for people with severe coronary artery disease or pre-existing heart failure.4PubMed Central. Disulfiram Use in an Elderly Man With Alcoholism and Heart Disease: A Discussion
One detail that surprises many patients is that the reaction isn’t limited to drinking beer or liquor. Alcohol in cough syrups, mouthwash, cooking wines, vinegar-based sauces, and even some topical products like aftershave can trigger it. The drug stays active in the body for up to two weeks after the last dose, so you can’t simply skip a pill the morning of a dinner party and expect to drink safely that evening.
Everyday Side Effects Without Alcohol
Even if you never touch alcohol while on disulfiram, you’ll likely notice some side effects. In a comparative trial that pitted disulfiram against naltrexone and acamprosate (two other medications for alcohol dependence), roughly a third of patients in each group reported at least one adverse event during the study. The most common complaints from the disulfiram group were tiredness and headache.5Alcohol and Alcoholism. A randomized, multicentre, open-label, comparative trial of disulfiram, naltrexone and acamprosate in the treatment of alcohol dependence Drowsiness, fatigue, and a metallic or garlic-like taste in the mouth are also widely reported.6iScience. A critical appraisal of disulfiram repurposing and off-label use trends from 2015 to 2025: A systematic review
These milder effects tend to improve over the first few weeks for many people, though the taste disturbance can be persistent and genuinely annoying. Some patients describe it as a constant faint garlic flavor that makes food less enjoyable. For most people, these are tolerable enough not to warrant stopping the drug, but they’re worth knowing about in advance.
Liver Injury
Liver damage is the side effect that draws the most medical concern. The tricky part is that many people prescribed disulfiram already have some degree of alcohol-related liver dysfunction, so telling apart damage caused by the drug from damage caused by drinking isn’t straightforward. The true incidence of disulfiram-related liver injury remains unclear for this reason.7PubMed Central. Disulfiram-Induced Acute Liver Injury
The severity can range from mildly elevated liver enzymes, which are detectable only on blood tests, to fulminant hepatitis that progresses rapidly toward liver failure and death. When liver biopsies have been taken, they tend to show inflammation in the portal areas of the liver along with eosinophils (a type of immune cell often linked to drug reactions) and dying liver cells.8PubMed Central. Disulfiram-Induced Acute Liver Injury
A review of adverse drug reaction reports found 82 cases of suspected disulfiram-related liver injury with at least a possible causal link. Among those, eight patients either died or required a liver transplant. In patients who had developed jaundice, the rate of death or transplant was about one in six. The median time from starting disulfiram to liver trouble was roughly six weeks. Interestingly, eosinophils showing up on a liver biopsy was actually a good sign, linked to recovery, while widespread hepatocyte death pointed toward a worse outcome.9PubMed. Clinical characteristics and prognostic markers in disulfiram-induced liver injury
In one screening study of 108 patients starting the standard 250 mg daily dose with initially normal blood work, a quarter developed elevations in a key liver enzyme (alanine aminotransferase) above the normal range within two to four weeks. About a third of the group had to be taken off the drug because of abnormal liver markers during that window.10Alcoholism: Clinical and Experimental Research. Screening for Disulfiram‐Induced Liver Test Dysfunction in an Inpatient Alcoholism Program That’s a substantial percentage, which is why liver monitoring is taken seriously.
Monitoring Your Liver on Disulfiram
Given how quickly liver problems can develop, clinicians who prescribe disulfiram generally recommend checking liver enzyme levels before treatment starts, then repeating the tests every two weeks for the first two months. After that, if things look stable, testing can shift to every three to six months.11PubMed. Disulfiram-induced fulminating hepatitis: guidelines for liver-panel monitoring This schedule is more frequent than what many patients expect, but the two-month window is when disulfiram-related hepatitis peaks.12PubMed. Disulfiram therapy–adverse drug reactions and interactions
Having moderately elevated liver enzymes at baseline doesn’t necessarily rule out disulfiram use. Research has found that with proper monitoring, most patients with modestly abnormal liver function can still take the drug safely.13PubMed. Disulfiram use in patients with abnormal liver function test results The key is catching a steep rise early rather than waiting for symptoms like jaundice or abdominal pain to appear, because by that point significant liver damage may already have occurred.
Nerve Damage
Peripheral neuropathy is one of the more unsettling side effects of disulfiram. It tends to follow a “length-dependent” pattern, meaning the longest nerves in the body are affected first. In practice, this means symptoms usually start in the feet and lower legs: numbness, burning pain in the soles, tingling, and weakness. In more advanced cases, patients develop a steppage gait or even foot drop, where the foot slaps the ground because the muscles that normally lift it during walking have weakened.14PubMed. Disulfiram neuropathy: two cases of distal axonopathy
The underlying problem is damage to the axon, the long cable-like extension of each nerve cell. Research suggests the culprit is carbon disulfide, a byproduct of how the body breaks down disulfiram.15PubMed Central. Disulfiram neuropathy: two case reports Carbon disulfide is a well-known industrial toxin that causes the same kind of nerve damage in workers exposed to it in manufacturing settings, so it’s not surprising that producing it inside the body has similar consequences.
Unlike liver injury, which tends to peak early in treatment, neuropathy risk increases with the duration of therapy.16PubMed. Disulfiram therapy–adverse drug reactions and interactions Dose also matters. In reported cases, neuropathy has appeared after as little as one month on a very high dose or after a couple of months on the standard dose.17PubMed. Disulfiram neuropathy: two cases of distal axonopathy The good news is that the damage is often at least partially reversible if the drug is stopped promptly once symptoms appear. The bad news is that some patients are left with residual numbness or weakness even after discontinuation.
Psychiatric and Neuropsychiatric Effects
Disulfiram can occasionally trigger psychosis, including paranoid delusions and hallucinations. The mechanism involves one of disulfiram’s metabolites, which blocks an enzyme responsible for converting dopamine into norepinephrine. When that conversion is impaired, dopamine accumulates in the brain, and excess dopamine signaling in certain pathways is closely associated with psychotic symptoms.18PubMed Central. Disulfiram Induced Psychosis
This side effect is uncommon but dramatic when it occurs. Patients and their families should know that new-onset confusion, paranoia, or bizarre behavior on disulfiram warrants urgent medical attention. The psychosis typically resolves after stopping the drug, but it can be frightening and dangerous in the meantime. Psychiatric reactions were among the four main categories of disulfiram adverse drug reactions identified in a long-term surveillance review, alongside liver, skin, and neurological problems.19PubMed. Disulfiram therapy–adverse drug reactions and interactions
Vision Problems
Less commonly discussed is disulfiram’s potential to damage the optic nerve. A retrospective review spanning nearly two decades found that among 14 patients referred for visual loss while taking disulfiram, five were diagnosed with a toxic optic neuropathy directly related to the drug. The reassuring part: all five recovered their visual acuity and visual field once the medication was stopped.20PubMed. Optic neuropathy while taking disulfiram
Blurry vision or changes in color perception while on disulfiram shouldn’t be dismissed as aging or fatigue. They deserve a prompt eye exam and a conversation with the prescribing doctor about whether the drug should be continued.
Skin Reactions
Skin problems are among the earliest side effects to show up. In long-term surveillance data, skin reactions peaked roughly two weeks after starting disulfiram, earlier than the onset of either liver or nerve problems.21PubMed. Disulfiram therapy–adverse drug reactions and interactions Rashes, itching, and occasional acne-like eruptions are the most common forms. A possible link between skin reactions and nickel allergy has been discussed in the medical literature, since one of disulfiram’s metabolites can chelate metals including nickel. If you have a known nickel allergy (the kind that makes cheap jewelry cause a rash), mention it to your doctor before starting disulfiram.
Drug Interactions
Disulfiram inhibits certain liver enzymes involved in drug metabolism, particularly an enzyme called CYP2C9.22PubMed. Cytochrome P450 isozymes and antiepileptic drug interactions This means it can slow the breakdown of other medications that use the same pathway, raising their levels in the blood and potentially amplifying their effects or toxicity. Anti-seizure medications like phenytoin are a well-known example: patients on both drugs may develop signs of phenytoin toxicity (dizziness, involuntary eye movement, unsteadiness) because the phenytoin isn’t being cleared fast enough.
Warfarin, the blood-thinning medication, is another interaction to watch. Disulfiram can raise warfarin levels and increase bleeding risk. Anyone starting disulfiram while on warfarin needs more frequent blood-clotting tests during the overlap period. Benzodiazepines, certain antidepressants, and isoniazid (a tuberculosis drug) also interact with disulfiram in ways that can strengthen sedation or increase toxicity. The general rule is to give your prescriber a complete medication list and flag any changes while on treatment.
What Happens in an Overdose
Intentional overdoses of disulfiram present an unusual clinical challenge because symptoms can be severely delayed. In one reported case, a patient who took a large amount of disulfiram without any alcohol initially seemed to improve after standard supportive care, only to lapse back into impaired consciousness five days later. The delayed relapse was accompanied by ketoacidosis, required dialysis, and took two additional weeks to resolve.23PubMed Central. Delayed onset of impaired consciousness complicated with ketoacidosis after disulfiram overdose The slow metabolism of disulfiram and its active byproducts explains this lag: the toxic metabolites continue to accumulate long after the pills have been swallowed.
Other reported overdose features include prolonged coma, seizures, and severe toxic encephalopathy with weakness in all four limbs that outlasts the period of unconsciousness.24Acta Neurologica Belgica. Delayed and prolonged coma after acute disulfiram overdose For emergency departments, the practical takeaway is that a patient who seems to be recovering from a disulfiram overdose needs extended monitoring, because the worst may still be ahead.
How Disulfiram Compares to Other Alcohol Medications
Patients sometimes ask whether switching to naltrexone or acamprosate would mean fewer side effects. The comparative trial mentioned earlier found that the overall rate of adverse events was not significantly different among the three drugs: roughly a third of patients in each group had at least one complaint. The type of side effect differed, though. Naltrexone users reported the most nausea, while acamprosate users reported more diarrhea. Disulfiram’s standout complaints were tiredness and headache.25Alcohol and Alcoholism. A randomized, multicentre, open-label, comparative trial of disulfiram, naltrexone and acamprosate in the treatment of alcohol dependence
Where disulfiram stands apart is the severity ceiling. Neither naltrexone nor acamprosate carries the risk of a life-threatening reaction to alcohol, fulminant liver failure, or the kind of peripheral neuropathy that can leave someone unable to walk normally. Disulfiram is a more effective deterrent precisely because the consequences of drinking on it are so harsh, but that same harshness means the safety profile carries a heavier tail of rare, serious events.
Off-Label Use and Emerging Risks
Disulfiram has attracted growing interest for conditions beyond alcohol dependence, including Lyme disease and various cancers. In cancer research, the drug’s ability to generate reactive oxygen species and inhibit aldehyde dehydrogenase in tumor cells has shown promise in laboratory settings.26PubMed Central. Advancing Cancer Therapy with Copper/Disulfiram Nanomedicines and Drug Delivery Systems Some Lyme disease patients have tried it based on preliminary evidence that it may have activity against the Borrelia bacterium.
These off-label uses bring their own side-effect concerns. In a study of 16 Lyme disease patients treated with disulfiram, 13 experienced toxic effects, primarily neurological: neuropathies, headaches, dizziness, difficulty concentrating, sleep disruption, and worsening fatigue. Several also reported increased joint pain and digestive problems.27PubMed Central. Potential Patient-Reported Toxicities With Disulfiram Treatment in Late Disseminated Lyme Disease A systematic review of disulfiram repurposing highlighted additional risks in off-label contexts, including encephalopathy in cancer patients and Jarisch-Herxheimer reactions in Lyme patients, which are severe inflammatory flares triggered by dying bacteria.28iScience. A critical appraisal of disulfiram repurposing and off-label use trends from 2015 to 2025: A systematic review
These newer applications sometimes involve higher doses or longer treatment durations than traditional alcohol-dependence prescribing, and the side-effect profile gets worse at both extremes. Neurotoxicity and hepatotoxicity become more frequent at higher doses or when disulfiram is combined with other medications.29iScience. A critical appraisal of disulfiram repurposing and off-label use trends from 2015 to 2025: A systematic review Anyone considering disulfiram for an off-label purpose should be aware that the safety data from alcohol-dependence studies may underestimate the risks they’ll face.
Genetic Factors That May Increase Vulnerability
Not everyone metabolizes disulfiram the same way, and genetic variation in the very enzymes the drug targets could make some people more susceptible to its toxic effects. Animal research has shown that when disulfiram is combined with another drug that also inhibits aldehyde dehydrogenase in subjects that already have low baseline activity of that enzyme, the risk of liver damage increases.30PubMed Central. Effects of the aldehyde dehydrogenase inhibitor disulfiram on the plasma pharmacokinetics, metabolism, and toxicity of benzaldehyde dimethane sulfonate (NSC281612, DMS612, BEN) in mice This is particularly relevant for people of East Asian descent, a substantial proportion of whom carry genetic variants that result in reduced or absent aldehyde dehydrogenase activity. These are the same variants responsible for the well-known “Asian flush” reaction to alcohol.
For someone who already flushes and feels nauseated from a single drink, adding a drug that further blocks the same enzyme is essentially doubling down on a metabolic bottleneck that’s already strained. While disulfiram prescribing decisions in this population aren’t settled by a single animal study, the biological logic is straightforward enough that it warrants a frank discussion with a prescriber. The flushing response itself is a real-world signal that your aldehyde dehydrogenase capacity is limited, and that information matters when weighing the risks of a drug whose entire mechanism depends on blocking that same enzyme even further.