Published: 15 December 2014

Can I Have a Drink With That?

Prescriber Update 35(4): 54
December 2014

Key Messages

  • Alcohol consumption should be avoided or minimised with many medicines.
  • Drugs that act on the central nervous system tend to increase the effect of alcohol, but other interactions are possible.

Alcohol is one of the most commonly used recreational drugs in New Zealand; however mixing alcohol and some medicines can be harmful. Probably the best known alcohol-drug interaction is an intentional one with disulfiram (Antabuse), prescribed to aid abstinence from alcohol. Disulfiram inhibits acetaldehyde dehydrogenase which blocks the metabolism of alcohol and leads to an accumulation of acetaldehyde in the blood. This disulfiram-alcohol interaction provokes a number of unpleasant symptoms: facial flushing, dyspnoea, palpitations, pyrexia, sweating, dizziness, throbbing headache, nausea and vomiting. Ingestion of large amounts of alcohol with disulfiram may also cause a drop in blood pressure that results in fainting and syncope (

Many medicines that act on the central nervous system may potentiate the depressant and other actions of alcohol. Benzodiazepines, zopiclone and sedating antihistamines are examples of medicines that act on the central nervous system. Other, less expected interactions are also seen, for example with selective serotonin re-uptake inhibitors (SSRIs) and other antidepressants. Exaggerated or pathological alcohol intoxication has been repeatedly observed in individuals who consumed moderate, previously well-tolerated quantities of alcohol. Many patients experienced memory impairment or mood change, whilst some exhibited aggressive and violent behaviour1.

Medsafe has previously noted cases of alcohol potentiation in patients taking varenicline (Champix) (

The table below provides further examples of medicines with which alcohol consumption should be avoided (this is not an exhaustive list).

Table 1: Examples of medicines that should not be taken with alcohol

Medicine Effects when taken with alcohol
Metronidazole Disulfiram-like effects
Sedating antihistamines Increased drowsiness and dizziness; impaired driving
Tricyclic anti-depressants Increased drowsiness and dizziness; impaired driving
Benzodiazepines and zopiclone Severe sedation, respiratory and/or cardiovascular depression; disinhibition
Methylphenidate Impaired concentration, dizziness, drowsiness
Warfarin Acute ingestion of a large quantity of alcohol can increase the INR, which increases the risk of pathological bleeding. By contrast, chronic heavy alcohol intake may induce the metabolism of warfarin reducing its effects
Monoamine oxidase inhibitors (MAOIs) Hypertensive crisis; increased alcohol effects
Sulphonylureas Exaggerated hypoglycaemic effects; sudden changes in blood pressure, other disulfiram-like reactions
Metoprolol Dizziness, fainting, drowsiness, arrhythmia
Statins Liver damage
Anti-epileptics Increased CNS depressant activity, increased risk of seizures, unusual behaviour, suicidal ideation
SSRIs Memory impairment, disinhibition, aggression

Please note this information is advisory only. Data sheets for individual medicines should be checked for information on possible alcohol interactions.

Prescribers are reminded that alcohol-drug interactions are common but have been little studied. Reports to CARM are particularly encouraged.

  1. Menkes DB, Herxheimer A (2014) Interaction between antidepressants and alcohol: signal amplification by multiple case reports. Int J Risk & Safety in Medicine 26: 163-170.