How Long Does Baclofen Stay in Your System? Half-Life, Detection, and What Affects It

When you take baclofen, you might wonder how long it’s really working - or when it’ll be completely out of your body. This isn’t just about when you feel the effects fade. It matters if you’re getting a drug test, planning surgery, switching medications, or worried about withdrawal. The answer isn’t simple, but it’s clear once you know the facts.

How long does baclofen stay in your system?

Baclofen has a half-life of about 2 to 4 hours. That means every 2 to 4 hours, your body removes half of what’s left. For most people, it takes around 10 to 20 hours for the drug to be mostly cleared from your bloodstream. But that doesn’t mean it’s gone from your system entirely.

Most of baclofen is eliminated through your kidneys in its original form - not broken down much by the liver. Because of this, people with kidney problems clear it much slower. In someone with healthy kidneys, 90% of a dose is gone within 24 hours. In someone with reduced kidney function, it can linger for days.

So while the active effects wear off in a few hours, traces of baclofen can still be detected in urine for up to 2 to 3 days after your last dose. Blood tests rarely test for baclofen unless it’s a forensic or hospital setting, but urine tests can pick it up for longer.

What affects how long baclofen stays in your body?

Not everyone clears baclofen at the same rate. Several factors change how fast or slow it leaves your system:

• Kidney function - This is the biggest factor. If your kidneys aren’t working well, baclofen builds up. People with chronic kidney disease may need lower doses or longer gaps between doses.
• Age - Older adults often have slower kidney function, so baclofen stays in their system longer. Dosing is usually reduced for people over 65.
• Dose and frequency - Taking higher doses or taking it multiple times a day means more drug accumulates. If you’ve been on baclofen for weeks or months, your body holds onto it longer than if you just took one pill.
• Hydration - Drinking enough water helps your kidneys flush it out faster. Dehydration slows clearance.
• Other medications - Drugs that affect kidney function, like NSAIDs (ibuprofen, naproxen) or certain blood pressure meds, can interfere with baclofen removal.

One real-world example: A 72-year-old man with mild kidney impairment took 20 mg of baclofen three times a day for spasticity. After stopping, it took him nearly 5 days to fully clear the drug - compared to a healthy 35-year-old who cleared it in under 24 hours.

Can baclofen be detected in drug tests?

Standard workplace or roadside drug tests don’t screen for baclofen. These tests look for illegal drugs like marijuana, cocaine, opioids, or amphetamines. Baclofen is a prescription muscle relaxant, not a controlled substance in most places, including Canada and the U.S.

But if a doctor orders a specific drug panel - say, after an overdose, accident, or unexplained drowsiness - baclofen can be detected in urine for up to 72 hours. In rare cases, like forensic toxicology after a fatal accident, labs can detect it even longer using advanced methods.

If you’re concerned about a drug test, don’t assume it’s invisible. If your job requires regular screening and you take baclofen, it’s smart to tell your employer or testing center ahead of time. Bring your prescription label. Most employers accept documented prescription use.

How does baclofen leave your body?

Baclofen doesn’t get broken down much by the liver. About 80% to 90% of it is excreted unchanged through your kidneys. That’s why kidney health is so important.

The rest - up to 20% - is metabolized into a few minor compounds, but none of these are active or toxic. They’re also cleared by the kidneys. No significant amount is removed through sweat, breath, or feces.

This makes baclofen different from other muscle relaxants like cyclobenzaprine or methocarbamol, which are heavily processed by the liver. If you have liver disease but healthy kidneys, baclofen is often safer than those alternatives.

What happens when you stop taking baclofen?

Stopping baclofen suddenly - especially after weeks or months of use - can cause serious withdrawal symptoms. This isn’t because the drug is still in your system. It’s because your nervous system has adapted to its presence.

Symptoms of withdrawal can start within 24 to 48 hours after the last dose and include:

• Hallucinations (seeing or hearing things that aren’t there)
• Seizures
• High blood pressure
• Increased muscle tone or spasms
• Agitation, anxiety, or insomnia
• Fever

These symptoms can be life-threatening. That’s why doctors never tell patients to quit baclofen cold turkey. Tapering down slowly - over days or weeks - is the only safe way to stop.

Even if the drug is mostly gone from your blood after 24 hours, your brain still needs time to readjust. Withdrawal isn’t about how long baclofen stays in your system - it’s about how long your body took to adapt to it.

When should you talk to your doctor?

You should call your doctor if:

• You miss a dose and aren’t sure whether to take it late
• You’re planning surgery and need to stop baclofen
• You have kidney problems and are unsure about your dose
• You’re experiencing dizziness, confusion, or weakness that feels worse than normal
• You want to stop taking it - never do this on your own

If you’ve been on baclofen for more than a few weeks, your doctor will likely give you a tapering schedule. This might mean reducing your dose by 5 mg every 3 to 7 days, depending on your situation.

Some people take baclofen for years without issue. Others need to switch because of side effects or kidney changes. There’s no one-size-fits-all timeline. Your doctor knows your history - use that knowledge.

How to speed up clearance (and what won’t work)

There’s no proven way to make baclofen leave your body faster. Drinking extra water helps your kidneys work better - but only if they’re healthy. Diuretics (water pills) won’t help and can be dangerous.

Detox teas, activated charcoal, or sauna sessions? They don’t work. Baclofen isn’t stored in fat or processed by the liver, so these methods have no effect.

The only reliable way to clear it? Time - and healthy kidneys. Stay hydrated, avoid NSAIDs, and let your body do its job.

Bottom line

Baclofen is gone from your bloodstream within a day for most people. But it can show up in urine for up to 3 days. For those with kidney issues, it can linger much longer. The real risk isn’t detection - it’s withdrawal if you stop suddenly.

Always follow your doctor’s instructions. Never adjust your dose or quit without talking to them. If you’re worried about how long baclofen stays in your system, the best answer is always your medical team - not internet guesses.