Antabuse (Disulfiram)

How does it work?

This medicine contains the active ingredient disulfiram, which is a type of medicine called an aldehyde dehydrogenase inhibitor. It is prescribed to recovering alcoholics to help them abstain from drinking alcohol. If someone taking this medicine drinks alcohol, it quickly causes a severe, unpleasant and potentially dangerous reaction and knowledge of this fact can help to stop people from drinking.

Disulfiram works by interfering with the way the body metabolises alcohol. Alcohol is broken down in the body to a compound called acetaldehyde. This is then normally broken down further by an enzyme in the liver called aldehyde dehydrogenase. Disulfiram stops this enzyme from working. This means that when alcohol is consumed, the body cannot process it normally. Instead, acetaldehyde accumulates in the bloodstream.

High levels of acetaldehyde act directly on the heart and blood vessels, causing flushing, a racing heartbeat and a drop in blood pressure that causes dizziness. Other unpleasant symptoms include headache, shortness of breath, palpitations, nausea and vomiting. This reaction to alcohol is often called the disulfiram reaction and is usually enough to deter people from having another drink.

The disulfiram-alcohol reaction occurs within ten minutes of ingesting alcohol and may last for several hours. It can be potentially dangerous. For some people, knowing that they cannot drink alcohol without having this reaction is what is needed to help them being tempted in a weak moment.

When starting this medicine you must not have drunk alcohol for at least 24 hours. You must not drink alcohol for one week after stopping the medicine, as the reaction may still occur in this time.

What is it used for?

  • Alcoholism - to deter people with an alcohol problem from drinking


  • You must not drink alcohol while you are taking this medicine, or for one week after stopping this medicine, as alcohol will cause the disulfiram reaction. Symptoms include flushing, a racing heartbeat, dizziness, headache, shortness of breath, palpitations, nausea and vomiting. The reaction can be potentially dangerous.
  • Certain foods, liquid medicines, remedies, tonics, toiletries, perfumes and aerosol sprays may contain sufficient alcohol to cause a disulfiram-alcohol reaction. You should also take care with low alcohol and “non-alcohol” or “alcohol-free” beers and wines, as these can also provoke a reaction when consumed in sufficient quantities.
  • If you get some of the symptoms of the disulfiram reaction, either from drinking alcohol, or from exposure to a certain amount of alcohol from sources such as those listed above, you should contact your doctor.

Use with caution in

  • Diabetes
  • Disease affecting the airways or lungs (respiratory disease)
  • Epilepsy
  • Kidney failure
  • Liver disease

Not to be used in

  • Coronary heart disease
  • Heart failure
  • High blood pressure (hypertension)
  • History of stroke
  • Severe personality disorders
  • Psychotic illness
  • People who are at risk of suicide
  • Breastfeeding

This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and Breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

  • This medicine should only be used during pregnancy if the expected benefit to the mother and foetus is greater than the possible risk to the foetus. It should be avoided in the first trimester. Seek medical advice from your doctor.
  • There is no information available about the safety of this medicine during breastfeeding. For this reason it should not be used by breastfeeding mothers, particularly if there is a chance that it may have a reaction with medicines that the baby is taking. Seek medical advice from your doctor.

Label warnings

  • This medication may cause drowsiness. If affected do not drive or operate machinery. Avoid alcoholic drink.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

  • Drowsiness
  • Tiredness
  • Nausea and vomiting
  • Bad breath
  • Decreased sex drive
  • Mood changes, strange or abnormal thoughts or depression
  • Allergic skin rash
  • Liver problems

The side effects listed above may not include all of the side effects reported by the drug's manufacturer.For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

How can this medicine affect other medicines?

It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to ensure that the combination is safe.

Certain liquid medicines, remedies, tonics, toiletries and aerosol sprays may contain sufficient alcohol to cause the disulfiram-alcohol reaction. Make sure you check the ingredients or ask your pharmacist.

Disulfiram increases the anti-blood-clotting effect of the anticoagulant warfarin. If this medicine is used in combination with warfarin, a smaller than normal dose of warfarin may be needed to avoid bleeding.

Disulfiram inhibits the metabolism of the following medicines and may therefore increase their blood levels and risk of side effects:

  • chlordiazepoxide
  • benzodiazepines such as diazepam and temazepam
  • imipramine
  • desipramine
  • phenytoin
  • theophylline.

If any of the following are taken with this medicine there may be an increase in confusion and changes in mood:

  • isoniazid
  • metronidazole.

Paraldehyde should be avoided in people taking this medicine.

Amitriptyline may increase the effect of disulfiram and people taking it may experience a more intense disulfiram-alcohol reaction if they drink alcohol.