Can I Legally Drive the Day After Taking MDMA or Ketamine in Ireland?

A real Reddit user asked the question. The replies were heated. The law is clear.

Can You Drive the Day After Taking MDMA or Ketamine in Ireland?

A Reddit user recently asked:

“Does anyone know if driving the day after the use of MDMA and ketamine is legal? I obviously won’t be under the influence but will be having my share over a weekend festival.”

It’s a common question.

“if I leave the same amount of time I’d leave

after a drinking session I should be ok”?

This is dangerously wrong and leads to a

high proportion of motorists being prosecuted

for drug driving"

But instead of help, the replies turned hostile. There was shouting, sarcasm, and a lot of misinformation. People said things like:

“You don’t need a law degree to know the answer.”

“If you’re not impaired, what’s the issue?”

“This isn’t legal advice, it’s stupidity.”

If you’re asking this question after a festival — you’re already doing better than most.

A lot of people take something on a Saturday night and drive home Sunday without giving it a second thought.

But if you're reading this, it means that at least you’re trying to make an informed decision.

So here’s what Irish law actually says.

1. The law is zero-tolerance — not impairment-based

Unlike alcohol, Ireland’s drug driving laws don’t care how you feel.

And that’s the important point here: most people treat drugs like alcohol.

Like alcohol, if you wait an appropriate period of time (12-14 hours after drinking) you should be fine to drive. They assume drugs act in the same way. The thinking goes:

“if I leave the same amount of time I’d leave after a drinking session I should be ok”.

This is dangerously wrong and leads to a high proportion of motorists being prosecuted for drug driving.

If your blood contains even trace amounts of certain “specified drugs” — including MDMA, ketamine, cannabis (THC), or cocaine — you can be prosecuted.

That’s because section 4 of the Road Traffic Act makes it illegal to drive with any detectable level of these substances above set thresholds.

There’s no need for Gardaí to prove you were impaired.

Detection = charge.

Conviction = 1-year driving ban.

Minimum.

2. There is no “safe timeframe” for driving after drug use

The MBRS does not give advice on when it is safe to drive after taking alcohol or drugs. That’s important. They’re a scientific body, not a source of legal reassurance.

The only official position is caution.

The detection time varies depending on your:

• Dose

• Metabolism

• Body weight

• Hydration

• Sleep

  
  

  … and dozens of other individual factors.

So even if you feel sober, your blood may still contain traces.

"As he had broken the law he could be

legally tested for drugs, even if no suspicion

of impairment existed.

Cocaine showed up on his saliva sample.

He was arrested, gave a blood sample —

and came back over the limit"

3. What are metabolites — and why do they matter?

Clients often ask:

“If I took it 24 hours ago, how can it still show up?”

Because your body continues to break the drug down — and that process can take time.

It takes a lot longer than alcohol.

Here’s how the MBRS explains it:

“Metabolites are breakdown products that are produced by the body to aid elimination of a drug through excretion. Metabolites can be active or inactive pharmacologically. The term used to describe how long a drug takes to break down in the body is called the half-life. A half-life of 1 hr means that 50% the drug will be broken down in 1 hr, 75% at 2 hrs and so on.”

In plain English:

When you take a drug, your body starts breaking it down.

The bits it breaks it into are called metabolites.

Some of those metabolites still affect your body, and some don’t — it depends on the drug.

There’s a scientific term for how quickly this happens: it’s called the half-life.

A half-life just means the time it takes for half the drug to leave your body.

So if a drug has a half-life of one hour:

·       After 1 hour, half of it is gone

·       After 2 hours, only 25% is left

·       After 3 hours, you're down to 12.5%, and so on

Even when the main drug has worn off, its metabolites can still show up in a test — and sometimes, that’s enough to get you charged.

That’s why even the next day, a small amount can still be detected — and still lead to prosecution.

"He was shocked. He felt fine.

He assumed it was out of his system.

But it wasn’t.

And he was facing a mandatory 1-year ban"

4. Real clients are being charged — even when they feel fine

This isn’t theoretical.

One client took cocaine on a Thursday night. Slept well.

Drove home Saturday afternoon.

He was stopped for speeding.

As he had broken the law (speeding) he could be legally tested for drugs, even if no suspicion of impairment existed.

Cocaine showed up on his saliva sample.

He was arrested, gave a blood sample — and came back over the limit.

He was shocked. He felt fine. He assumed it was out of his system.

But it wasn’t.

And he was facing a mandatory 1-year ban.

5. “The roadside test doesn’t cover MDMA — so I’m safe, right?”

Wrong.

While MDMA and ketamine may not be detected on the SecureTec device (the roadside saliva test), Gardaí can still arrest you based on one or more of the following:

• Your appearance

• Your behaviour

• A statement you make

• Prior information or suspicion

Once arrested, you will be required to allow a doctor or nurse take a blood or urine sample at the Garda station. That’s what matters — and that’s what the MBRS will test in the lab.

6. What did the Reddit thread get wrong?

• They assumed impairment is required. It isn’t.

• They mocked the question — instead of answering it.

• They treated a common concern as a criminal mindset.

That’s not helpful.

The truth is: people ask this question because they care.

They want to avoid mistakes. They want to understand the law.

And the only responsible answer is one grounded in fact, not judgment.

7. So... can I drive the next day?

If you’ve taken MDMA, ketamine or any drug listed under the zero-tolerance law, there is no guaranteed “safe” timeframe. Even 24+ hours later, you will very likely still test positive.

"A prosecution doesn’t require

any scientific proof of drugs in your system.

Read that again"

If you’re not certain the drug is out of your system — don’t drive.

Because if you are over the threshold:

• There’s no defence of “I felt fine”

• There's no forgiveness for “I thought it would be gone”

• There’s no workaround for “it was only once”

• Judges understand alcohol (they drink themselves you know) but they have less toleration for drugs.

Remember, even if the drug didn’t show up on the roadside device, if the Garda felt that your demeanour indicated that you are impaired in some way due to drugs, you will be arrested for “intoxicated driving”.

A prosecution here doesn’t require any scientific proof of drugs in your system.

Read that again.

And the penalties are substantial: 4 years disqualification.

After all, it’s the choice between going off the road or driving home.

And everybody wants to drive home.