You’re staring at the morning-after pill on your nightstand, and your head is pounding from last night. It’s a stressful spot to be in. Honestly, the first thing most people worry about isn’t the headache; it’s whether that bottle of wine or those three margaritas just sabotaged their backup birth control.
The short answer? Alcohol doesn't make Plan B stop working.
There is no chemical interaction where booze "deactivates" the levonorgestrel in the pill. That’s the good news. But it’s not exactly a simple "green light" situation either. There are side effects, timing issues, and some pretty gross biology that can mess things up if you aren't careful. If you’re looking for a straight-up medical breakdown of how Plan B and alcohol interact, you’ve come to the right place. Let's get into the weeds of what actually happens in your body.
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The Science of Levonorgestrel and Your Liver
Plan B is basically a massive dose of levonorgestrel. It’s a synthetic hormone that tells your ovaries to stay put and not release an egg. If there’s no egg, the sperm swimming around from last night have nothing to fertilize.
It’s a race against time.
When you drink, your liver gets busy. It’s the primary organ responsible for breaking down both the alcohol in your system and the medication you just swallowed. You might think that because the liver is "distracted" by the alcohol, it won't process the Plan B correctly. However, clinical data doesn't back that up. According to the FDA and manufacturers like Foundation Consumer Healthcare, there is no known contraindication between alcohol and levonorgestrel.
Your body is remarkably good at multi-tasking. It can process the tequila and the hormone at the same time. The efficacy of the pill—which is roughly 87% if taken within 72 hours—remains the same whether you are sober or have a 0.08 BAC.
The "Vomit Window" is the Real Danger
Here is where things get tricky.
Plan B is notorious for causing nausea. It’s the most common side effect. Now, add a hangover or lingering alcohol-induced stomach irritation to the mix. If you take Plan B and then throw up within two hours, you have a problem.
Basically, if the pill hasn't been in your system for at least 120 minutes, your body probably hasn't absorbed enough of the hormone to stop ovulation. If you puke it up, it’s like you never took it. You’ll likely need to go back to the pharmacy, buy another $50 pill, and try again once your stomach settles.
This is the most common way Plan B and alcohol fail together. It’s not about the chemistry; it’s about the mechanics of keeping the pill down.
If you’re feeling shaky, wait a bit. Drink some water. Eat a couple of crackers. Don’t rush the pill if you think it’s just going to come right back up.
Why the Hangover Feels Worse
You might notice that taking emergency contraception while hungover feels like a special kind of hell. There’s a reason for that. Both alcohol and Plan B can cause:
- Dizziness
- Fatigue
- Abdominal pain
- Breast tenderness
- Intense headaches
When you combine them, you’re essentially doubling down on these symptoms. The progesterone-like hormone in the pill can make you feel bloated and sluggish, which is exactly how a hangover feels. It’s a recipe for a very long day on the couch.
Does it Matter What You Drank?
Not really. Whether it was craft beer, cheap vodka, or a fancy cocktail, the ethanol is what matters. There is zero evidence that specific types of alcohol interact differently with emergency contraception.
What does matter is your judgment.
Often, the conversation about Plan B and alcohol isn't about the morning after—it's about the night before. Alcohol lowers inhibitions. It makes people forget to use a condom or skip their daily birth control pill. That’s usually why someone needs Plan B in the first place.
If you find yourself in this loop frequently, it’s worth looking into "set it and forget it" methods like an IUD or the Nexplanon implant. They don’t care how much you drink.
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The Myth of Decreased Efficacy
You might see TikToks or old forum posts claiming alcohol thins your blood and makes Plan B "wash out" of your system faster.
That is fake news.
Levonorgestrel works by thickening cervical mucus and delaying ovulation. It doesn't rely on blood thickness. It relies on hormone receptors in your brain and ovaries. Alcohol doesn't block those receptors.
A Word on Weight and Metabolism
While alcohol isn't a huge factor in Plan B failure, body weight actually is. This is something many people miss.
Studies, including research highlighted by Planned Parenthood, suggest that Plan B (levonorgestrel) may be less effective for individuals who weigh over 165 pounds or have a BMI over 25. In those cases, doctors often recommend Ella (ulipristal acetate) or a copper IUD.
If you are in a higher weight bracket and you’ve been drinking, the alcohol is the least of your worries. The dosage of the hormone itself is the bigger concern. Ella, however, requires a prescription, whereas Plan B is over-the-counter. If you choose Ella, you definitely want to be careful with alcohol, as it's a different chemical compound, though even then, there's no major "do not drink" warning on the label.
Real-World Advice for the Morning After
If you're currently dealing with the Plan B and alcohol crossover, stop scrolling and follow these steps.
First, hydrate. Your liver is working overtime. Give it some water to help move things along.
Second, check the clock. You have 72 hours for Plan B to be effective, though it works best the sooner you take it. If you are still actively drunk or feeling like you might vomit, wait an hour or two until you can keep a light snack down.
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Third, take the pill with food. A piece of toast or a banana can act as a buffer. This reduces the chance of the pill irritating your stomach lining and causing that dreaded "vomit window" failure.
Fourth, keep an eye on your cycle. Plan B is famous for messing with your next period. It might be early, it might be late, or it might be much heavier than usual. This is normal. It doesn't mean the alcohol caused a problem; it just means the hormones are doing their thing.
When to See a Doctor
Most of the time, you'll be fine. But if you experience severe, one-sided abdominal pain a few weeks after taking Plan B, go to the ER. While rare, emergency contraception can increase the risk of an ectopic pregnancy if the pill fails.
Also, if your period is more than a week late, take a pregnancy test. Even if you did everything right, no backup method is 100% effective.
Actionable Next Steps
- Take the pill immediately if your stomach is stable. Don't wait for the "perfect" moment of sobriety if you aren't feeling nauseous.
- Avoid more alcohol for the next 24 hours. Your body is already processing a high dose of hormones; don't make it work harder.
- Eat a small, bland meal before taking the medication to prevent vomiting.
- Track your symptoms. Note the date you took the pill so you aren't surprised when your period arrives at an odd time.
- Set a reminder for a pregnancy test in three weeks. This is the only way to be absolutely sure the Plan B worked.
- Consider long-term options if this is a recurring stressor. Talk to a provider about an IUD or the pill if you want a safety net that isn't dependent on a pharmacy run.