Prescription drugs and alcohol—time between?

Many (most) prescription drugs come with varying levels of warning about consuming alcohol. Everything I’ve seen about metabolizing alcohol relates to driving. I don’t think it’s a safe assumption that the criteria are the same, but that’s pure intuition. Is the general one-hour-per-ounce guideline related solely to impairment, or after an hour is the alcohol completely broken down and pharmaceuticals are safe to take?

I do think it is a safe assumption that answers can only be generalized—an antibiotic will be different from a muscle relaxant; whether the drink is before or after the medication time; how much is consumed; how often one drinks, etc. Therefore, all that I’m looking for is general information, not medical or specific advice; you are neither my doctor nor my lawyer.

It’s not just about impairment, although that’s definitely a factor with some medications, especially those with drowsiness as a side-effect. But your other risk is kidney or liver damage, because some medications need to be metabolized by the same enzymes your body is using to break down the alcohol, and if those enzymes are busy you can get a toxic buildup and damage some organs. Acetaminophen and alcohol is a notorious example. They don’t mix, but it’s not because you’ll get woozy and crash the car. You’ll just kill your liver.

Incidentally, there are lots of other medications that come with weird warnings like not to take with grapefruit juice. That’s for a similar reason - tying up the enzymes needed to break down drug by-products. Or to transform the drug into its useful form - some medications aren’t “active” until the liver does its thing on them.

There are some cases where the body’s metabolic response to alcohol can significantly change the effects of a drug, even without the presence of alcohol. It’s a problem for alcoholics, regardless if they have any alcohol in their system. Basically their liver has cranked up alcohol metabolizing enzymes, and these enzymes can alter how a drug is metabolized. For tylenol, this results in a much more rapid production of toxic metabolites, which is why alcoholics can OD on very small doses. Conversely, I believe there are other drugs that can be cleared more rapidly by this metabolic response, reducing their effectiveness.

This is, of course, in addition to many more direct interactions between drugs and alcohol.

There’s just too much “it depends” to give a one size fits most answer.

The elimination half life of Ambien is about 2.5 hours - so it’s generally gone within a day and then you can have a drink, for example.

If you’re not an alcoholic and don’t have liver disease, you *can *take a couple of Tylenol even with a drink, but if you are an alcoholic or have liver disease, you shouldn’t take it for at least a day after drinking (and we’d really rather you didn’t use Tylenol at all.)

Drinking alcohol with ibuprofen or other NSAIDS can increase the risk of stomach bleeding, so it’s best not to drink while the NSAID is active - about 6 hours after the last dose.

A pharmacist is the best person to ask if it becomes an actual question in real life.

What about vitamins? My wife was shocked one time to see me washing down a multivitamin with a glass of wine, which in retrospect might have been kind of silly on my part.

Eh, you probably just made expensive pee. The problem with alcohol and vitamins (assuming you’re not an alcoholic, which has its own slew of vitamin related problems) is that the alcohol in your stomach can break down the vitamin pill more quickly than it was intended to break down, and the alcohol in your system can impair the absorption of some of those vitamins - particularly the fat soluble ones. It’s not something you need to worry about like the interactions with drugs, but it was probably a waste of the vitamin pill.

So how long does it take to metabolize alcohol so it’s unlikely to cause a problem? Assume a non-alcoholic (not a teetotaler; maybe 1 to 2 drinks a night once or twice a week; rarely drinks to intoxication) of average height and build, and just two drinks consumed over an hour or so. (Also, assume it’s a bottle of Springbank 18.) Two hours after the last sip, is there likely (on average, generally, etc.) to be any traces of alcohol (or its metabolites) left? Three hours? A day?

If I’m understanding correctly, the reverse is wholly dependent on the drug and its half-life.

Oh, I was really hoping you wouldn’t ask that! :wink:

Metabolism and excretion of alcohol is so dependent on age, gender, ethnicity, body weight, fat percentage, hydration level, drinking history, and the action of 6 different enzymes that there’s no hard and fast answer. Alcohol is believed (but we’re not certain) to have parallel fist-order and Michaelis-Menten elimination kinetics for elimination, which makes the math even more complicated.

If I was counseling a patient who could not call a pharmacist for a better answer, I’d say to wait at least one hour more than the number of drinks you’ve had before taking a drug that can interact with alcohol. So two drinks, wait 3 hours after your last drink. That seems in line with this chart showing BAC in fasting men.But that’s a rule of thumb, not something hard and fast.

I just want to stress the point about Tylenol (Acetaminophen, or paracetamol depending on where you are), the problem with Alcohol and Tylenol is that the alcohol uses up the enzymes that metabolize the toxic metabolites of Tylenol. So, it is actually more dangerous to use Tylenol the day after drinking (like for a hangover), then while drinking. While ibuprofen and other NSAIDs the risk is stomach bleeding (as Whynot said), so you shouldn’t take those at the same time, but would be perfectly safe to take for a hangover.

As for the OP, there are really too many variables to consider to give you an answer. Some of the warnings on prescription drugs is more a CYA because it can make you more drowsy, while some are due to an interaction between the alcohol and the medication. Some interactions are minor, some are major, and some will make you NEVER want to drink again (the ones that cause an Disulfiram-like reaction, like Metronidazole (Flagyl) ). Sometimes the problem can be caused by a single glass, sometimes you have to actually get drunk to matter. Basically, there are WAY too many variables to give you blanket advise.

I’ll stress what Whynot said, and ask your pharmacist, we are the ones who would know when you can drink with a particular medication better then anyone. If you have a question, feel free to ask us when you pick up your medication, or buy your OTC products, or just give us a call. You’ll find your pharmacy’s number on your RX vial.