Sleep Related

Is it Safe to Combine ZzzQuil and Alcohol?

zzzquil and alcohol

Unfortunately, too many people think you can combine different sleep medication with alcohol. Today we’re going to discuss ZzzQuil and alcohol. Is this a dangerous combination? And is it smart to use ZzzQuil medication and alcohol before sleep even faster? The short answer is no…

The answer is that they’re quite some complications when you take ZzzQuil and alcohol together. They can both cause drowsiness and if you take them in large quantities they can cause their side effects. In this article we’re going to discuss most of the side effects that combining both can cause you.

Can you combine ZzzQuil and alcohol?

No, as it’s a dangerous combination. However, it’s all about the dosage. If you’ve taken a glass of wine at dinner, and then you’re taking ZzzQuil around 11 at night, then there’s no problem. Your body will have already handled the alcohol, and there will be no interactions anymore. However, what is dangerous is if you’re having several drinks, or if you’re binge drinking, and then taking ZzzQuil to fall asleep. So it’s better to not mess around with this.

Active ingredient of ZzzQuil is diphenhydramine (benadryl)

The reason why alcohol does not mix well with ZzzQuil is because the active ingredient in it is diphenhydramine. This substance is also better known as benadryl. Here’s a short description of benadryl (taking from my article comparing melatonin and benadryl):

Diphenhydramine on the other hand is a drug that is being used against a wide variety of disorders (such as insomnia, anxiety, allergies, movement disorders and nausea), and can cause adverse reactions. It’s also possible to overdose on the drug, which is a magnitude easier to do with diphenhydramine vs melatonin. It’s estimated that on average, users will fall asleep within 30 minutes of taking Benadryl.

Side effects when mixing ZzzQuil and alcohol:

Since alcohol and ZzzQuil are both depressants, their effect will strengthen each other. Here are the side effects of taking alcohol and ZzzQuil:

Note: especially with alcohol, the effect is dosage dependent. Having 1 glass won’t make too much of a difference. Having 10 glasses with ZzzQuil, however, will definitely make you feel bad in the morning.


Now, since both alcohol and ZzzQuil cause lethargy and drowsiness, this effect gets pronounced when you combine them. For some, this may seem as a desirable effect, but it’s not.

Alcohol will help you fall asleep in the beginning, but later on during the night, you will wake up often.

If you want to fall asleep well, it’s best to stick with just diphenhydramine. Otherwise you will hamper your sleep. And wake up with the exact opposite effects.

This increased lethargy and drowsiness can be especially dangerous if you still have responsible tasks to do. Driving under influence of alcohol is already dangerous – add to that ZzzQuil and you might well pay with your life for that.

So it’s definitely not recommended to combine ZzzQuil and alcohol and then do something that you need your full sensen for.


One other thing that can happen if you drink alcohol and then take ZzzQuil is that you become unconscious. This is very dangerous, since you can slip and fall.

Thirst and dehydration

Everybody knows that alcohol dehydrates. But did you know that benadryl (and thus ZzzQuil) also dehydrates your body? So when you combine both, you also double the dehydration effects. Which in turn makes the alcohol cause more damage. It’s also incredibly uncomfortable and your hangovers will be even worse.

Memory loss

One study found that long term dosage of benadryl can cause dementia. The link between this is that anticholinergic drugs (such as ZzzQuil) block the effect of acetylcholine, which is involved in learning and memory. Alcohol is also linked with this, and such a combination will make things worse.

Can drinking alcohol and taking ZzzQuil kill you?

The answer is yes. The chances of this are small if you just drink several glasses and take a tab to sleep. However, if you drink more, and you still have things to do. For example driving, then this combination is very dangerous, as you can pass out.

So, just drinking one glass at dinner and taking ZzzQuil several hours later is unlikely to cause any adverse effects. However, more alcohol and closer together will very likely be an unpleasant experience. And you will wake up feeling lethargic and with a hangover. So the exact opposite of what you’d want when taking ZzzQuil.

One person describes his experience

“It was a typical Sunday night, and I wasn’t ready to let go of the weekend yet, so I popped open a bottle of red wine and proceeded to drink the whole thing (about 4 glasses) over the course of about an hour. Feeling slightly loopy and with my inhibitions dulled, I spontaneously decided to swallow 6 Unisom Maximum Strength capsules, each containing 50mg diphenhydramine, for a total of 300mg. I figured that the worst case scenario would be to fall asleep and wake up groggy in the morning. The best case scenario might be an enjoyable, introspective experience. About an hour later I began to realize that the possibilities could be much worse.

I was lying on the couch watching a movie, and began to have extreme difficulty keeping my eyes open. I also had a strong medicine taste in the back of my throat. My muscles began to ache, and I was having trouble focusing on anything. My vision was distorted and it became very difficult to follow the action on the TV screen. I decided to grab a blanket and just pass out on the couch. As I lay there trying to let myself fall asleep, I felt more and more uncomfortable, both physically and mentally. Thought patterns were highly non-linear and my attention floated groggily from one idea to another without coming to any natural conclusions. Short term memory was virtually nonexistent. Images on the TV screen melted together, as did sounds, many of which were not even there, in retrospect. While my heart rate seemed close to baseline, my breathing was extremely slow. Gradually I drifted off to sleep (around 2 AM, T+2hr), which was really more like a drunken stupor than actual sleep.”

Source (read the entire story)

By Adrianus

Since childhood I've tried hundreds of little experiments to feel better, learn faster and perform higher (e.g. supplements, sports, psychological tricks, sleep and wacky diets).
After I graduated university in 2016, I basically found that sleep was the #1 factor to improve every aspect of life.
Bad sleep = bad life. I started SleepInvestor in 2017 to share my experiments and thoughts about sleep.

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