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Alcohol and Medicines

Alcohol is an integral part of individual and social life in Europe. From work events to personal relaxation it is consumed frequently by a large part of the adult population.

However, alcohol is itself a drug that combines with receptors in the body to affect biological and chemical processes (and also behaviour) both in the short-term and the long-term. Therefore, it is an important factor to consider when taking other prescription/over-the-counter drugs.

Direct Interactions

Alcohol can interact directly to alter the effectiveness of other drugs. With short-term alcohol use, levels of other drugs are often increased, posing a risk of toxicity. With long-term use, the body often doesn’t respond to other drugs as well, making them less effective.

Two important common medications affected in this way are Warfarin’s blood-thinning ability, causing a risk of clotting or bleeding and Phenytoin’s level of seizure control, making one more likely to happen.

Some medications such as Metronidazole (antibiotic) and Verapamil (blood pressure/heart medicine) can work the other way, affecting the normal metabolization and levels of alcohol in the body.

Indirect Interactions

More commonly alcohol interacts with other medications through their combined effect on the body.

Alcohol alone results in altered mood and behaviour and an overall sedative effect. It leads to dehydration and dizziness, changes in blood pressure and puts extra strain on the heart. It also irritates the stomach lining and makes the liver work harder.

So when taken alcohol is taken in combination with other drugs that have the same effects it can cause the following:


Antihistamines Allergy/Flu Drowsiness


Zopiclone Anxiety Drowsiness, slow breathing

Antiepileptics Epilepsy Drowsiness, slow breathing, less movement control

Non-steroidal anti

inflammatories (NSAID’s) Arthritis Stomach ulcers, internal bleeding, liver damage

Amphetamines Attention Deficit Hyperactivity Disorder (ADHD) Dizziness, increased heart rate

SSRI’s/others Depression Drowsiness, less movement control, liver damage

Metformin, Gliclazide Diabetes Headache, nausea, low sugar level

Verapamil, Thiazide,

Others Blood Pressure Dizziness, irregular heartbeat

Alpha blockers Enlarged Prostate Dizziness

Statins High cholesterol Liver damage


Nitrofurantoin/Others Bacterial/fungal infections Blood pressure changes, stomach pain, headache

Codeine, oxycodone Pain Drowsiness, slow breathing, less movement control

Special Interactions

Antibiotics have a varied interaction with alcohol. Most are considered safe to use with alcohol. However, Metronidazole results in a strong reaction and should be entirely avoided. Meanwhile, two common antibiotics Doxycycline and Erythromycin are notably less effective taken with alcohol or those who use alcohol frequently.

Paracetamol taken with alcohol can result in liver failure very quickly and depression or anxiety medications with alcohol can result in increased suicide thoughts – so alcohol should be completely avoided in these situations.

Herbal medicines such as St. John’s Wort, Kava and Lavender interact with alcohol too.

Special Groups

Extra care must be taken by women and the elderly, who are both more sensitive to the effects of alcohol.

Women retain higher levels of alcohol than men, due to their smaller size. Further, altered mood and behaviour present increased risks of unprotected sex and pregnancy.

The elderly have reduced body capabilities and retain alcohol levels for longer. They have more medical problems, are more likely to be taking several medications and are more vulnerable to accidents as a result of the side effects as well.

For those suffering from long-term alcohol addiction, there are medications that (ironically) take advantage of some of these interactions to help combat the dependency. Ask your doctor if they are suitable if you think they may be helpful to you.

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