Published: 15 December 2014

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Can I Have a Drink With That?

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Prescriber Update 35(4): 54
December 2014

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 (www.medsafe.govt.nz/profs/datasheet/a/Antabusetab.pdf).

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) (www.medsafe.govt.nz/safety/EWS/2013/varenicline-alcohol.asp).

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.

References

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.