Dry January: Drinking + medication = not a good combination

As we near the end of the month, in our final blog to mark Dry January, Joanna Lloyd talks about the risks of combining medication and alcohol, and why this should be taken very seriously.


I’m Joanna Lloyd, a pharmacist and a member of the clinical professional network at the NHSBSA.  Usually, I work at our Bridge House office in Newcastle, mainly leading work on the assessment of medical devices for prescribing, the monthly Drug Tariff, and also getting involved in wider pieces of work within the Pharmacy Specialist team.

We’ve all seen the warning ‘do not drink alcohol with this medicine’ at some point either on a prescribed medicine or on medicines we’ve bought from the pharmacy. But what does this mean, and how seriously should we take this advice? The answer is very!

Most people are probably aware that sometimes chemical interactions can happen between combinations of medications which are prescribed by your doctor. Fortunately, doctors and pharmacists are both trained to be aware of the potential for an interaction to happen and to avoid using risky combinations wherever possible – and if this is not possible, to monitor you carefully. But alcohol is a chemical you ingest, just like a ‘drug’, and it can also interact chemically with medication.

The next bit is complicated, but it explains why the effect of alcohol on medication should be taken seriously, and why the advice should always be followed.

Alcohol and medication can interact in one of two ways: the rate of breakdown (metabolism) of either the medication or alcohol can be altered; or the effects of the alcohol and medication can add together and become ‘toxic’ with this especially affecting the central nervous system (CNS). Alcohol is broken down in the liver by two proteins called enzymes, and depending on how much alcohol you drink on a regular basis (whether you are an occasional drinker or a heavy regular drinker) will change the way in which these enzymes breakdown the interacting medication, and the effect that this combination has on your body.  

Some of the most common interactions which people may have experienced will be the CNS side effects such as excessive drowsiness when combining alcohol with any morphine-like substance commonly found in pain-killers such as codeine, morphine, fentanyl, oxycodone, methadone etc. Other types of medication which have an action on the CNS include antidepressants; anti-epileptic drugs; benzodiazepines or antihistamines. If taken together with alcohol the effects can be unpredictable and potentially life-threatening.

The other types of interactions can be quite varied such as alcohol causing excessive lowering of blood pressure when combined with medication designed to lower blood pressure; severe nausea and vomiting with some antibiotics, antifungals and some antidiabetic drugs; enhanced blood-thinning action of warfarin; and increased risk of liver damage with retinoids (used for severe acne and prescribed by hospital consultants).

Of course, alcohol isn’t the only ‘recreational’ drug used by some people, but the diversity in chemical types makes it impossible to predict all the possible interactions with prescribed medication. Indeed, some of these might not even be known about yet because it’s not the kind of thing that people will generally discuss with their doctors, so many go unreported. It’s only perhaps when people are hospitalised and clinicians make the connection between the presenting symptoms and the possibility that they may be related to an illicit drug interaction that a formal report would be made.

The take-home message is always that you shouldn’t assume no news is good news. Check with your pharmacist or doctor if you’re unsure about any potential effects of alcohol (or any other ingested chemical) on your medication.