Have you ever been told not to have grapefruit juice with medicine and wondered why? Although grapefruit juice is not unhealthy on its own, it can have unintended effects on the body when another substance is present.
When a drug you are taking meets another substance in your body and has an unintended effect, this is known as a drug interaction. The other substance can be another medication, alcohol or even herbal remedies. Most interactions are minor, but some can have serious consequences.
Alcohol also has a reputation for interacting with medication. Common short-term side effects include nausea, dizziness, sleepiness, and accidents. Long term your risk of liver damage and heart problems can be higher if the wrong types of medication are mixed with alcohol.
Fun Fact: The grapefruit interaction effect was first discovered because grapefruit juice was used to hide the taste of alcohol in an experiment. The purpose of the experiment? To determine whether alcohol had a drug interaction effect with a medication.
Alcohol affects medication in a couple of ways. it can either work with or against the effects of medication. If the medication and alcohol work against each other, the medication becomes less effective, reducing or eliminating its benefits to you. On the other hand, if the effects of the alcohol and medication are similar, the effects can add onto each other, dangerously interfering with body functions such as wakefulness or even breathing. Sometimes alcohol can interfere with the way your body processes medication, making them dangerously potent or causing toxic substances which should be flushed out to linger in the body.
It goes the other way around too. Medication can just as easily interfere with how your body processes alcohol. Common medications such as aspirin, anti-depressants and cough medicines can all amplify the effects of alcohol on your body and inflate your BAC beyond what you expect.
The answer is 'all of them'. Most drugs have a good chance of interacting with alcohol. It's not just typical medications you need to be wary of; herbal remedies can also interact negatively with alcohol. Some common substances you should be wary of include cold and cough medication, pain killers, and drugs used to manage long term conditions such as heart disease, anxiety, and high blood pressure. Some serious interactions can arise from mixing alcohol with paracetamol, antihistamines and some herbal remedies such as St John's wort, chamomile and valerian. This is by no means a complete list, so make sure you're not just assuming that something is safe to take with alcohol.
Medications should have warning labels that advise when ingredients may interact with alcohol. it's important to read the labels and take their advice seriously. Follow the dosing recommendations on prescription bottles exactly. Even common over the counter medications can cause problems at the wrong dose.
Make sure to communicate with the doctor who is prescribing your medications. They should be able to tell you the risk of any interactions happening and advise you of when it's safe for you to consume alcohol. Keep them updated about any over the counter medications and herbal remedies you're taking, because even those can have interaction effects. Your pharmacist who is dispensing medication is also qualified to give you advice; just make sure to let them know about your circumstances and other medications you may be taking.
If you're unsure whether a medication interacts with alcohol, avoid drinking until you confirm it's safe with your GP or pharmacist (don't just stop taking your medication). They won't necessarily tell you to stop drinking. They may instead give you important information on how to reduce your risks and advise you of what situations to be careful in.