What Muscle Relaxants Do (And Why Your Bladder Notices)

Muscle relaxants calm down tight, painful muscles. The problem? They don’t just target your back or shoulders—they can also affect the muscles that control your bladder.

Some relaxants even mess with nerve signals, making it harder for your brain and bladder to stay in sync. This is why bladder control and medication can sometimes clash.

Common muscle relaxants that may impact bladder control include:

• Baclofen – Often prescribed for muscle spasms, it can reduce bladder tone and lead to retention or leaks.
  
  
• Tizanidine (Zanaflex) – Can lower muscle tone in the pelvic floor, contributing to leaks.
  
  
• Diazepam (Valium) – A benzodiazepine with muscle relaxant properties that can cause sedation and urinary incontinence.
  
  
• Methocarbamol (Robaxin) – Less commonly linked to bladder issues but can still affect nerve function.
  

Muscle Relaxants and Urinary Issues: Recognising the Signs

If muscle relaxants are messing with your bladder, you might notice:

• Leaks out of nowhere – Your bladder might let go before you’re ready.
  
  
• Can’t fully empty – You go, but it still feels like something’s left behind.
  
  
• Urgency roulette – Sometimes it’s a trickle, sometimes a full-on dash to the loo.
  
  
• Nighttime surprises – Waking up wet or needing more nighttime trips to the bathroom.
  
  
• Longer bathroom breaks – You sit, you wait, you feel like there’s more, but nothing happens.

All of these can be urinary incontinence side effects linked to your medication—especially if they’ve started after you began taking a muscle relaxant.

Why It Happens: Breaking Down the Bladder Connection

Your bladder is a team player—it relies on nerves and muscles working together to store urine and release it when you’re ready.

Muscle relaxants interfere with this teamwork in a few ways:

Relaxing the wrong muscles

Sure, they calm down tight back muscles, but they can also loosen the pelvic floor and sphincters, making it harder to hold things in.

Slowing down nerve signals

Some relaxants affect communication between your bladder and brain, delaying the “I need to pee” message.

Messing with muscle tone

If the bladder muscles relax too much, they can struggle to empty completely.

Causing drowsiness or sedation

You might not wake up in time to reach the toilet, leading to nighttime leaks.

How to Keep Your Bladder Happy While on Muscle Relaxants

The good news? You don’t have to choose between pain relief and bladder control. 

Here’s how to manage the leaks while staying comfortable:

1. Hydrate Smartly

Drinking less might seem like the answer, but concentrated urine can irritate your bladder and make things worse.

Sip water throughout the day, and ease up on caffeine and alcohol—they don’t help.

2. Get on a Bathroom Schedule

If your bladder is unpredictable, set regular bathroom breaks. Try every two to three hours to keep things under control.

If you’re waking up multiple times a night, avoid drinking fluids right before bed.

3. Strengthen Your Pelvic Floor

Since relaxants can weaken bladder support, pelvic floor exercises can help you regain control. A few minutes a day makes a difference.

If you’re not sure how to do them properly, a pelvic health physiotherapist can help.

4. Use Protection (Just in Case)

If leaks are frequent, absorbent liners or incontinence pants like Invizi can be a game-changer. Light protection for small leaks, something more absorbent if full voids are happening.

Wearing protection doesn’t mean giving in—it just means staying comfortable.

5. Adjust Your Positioning

Struggling to fully empty? Try leaning slightly forward on the toilet and pressing gently on your lower abdomen.

Some people find sitting on the toilet with feet slightly elevated (like on a small stool) helps.

6. Watch What You Eat

Certain foods can irritate the bladder, making symptoms worse. Common culprits include spicy foods, citrus, artificial sweeteners, and carbonated drinks.

If leaks are becoming more frequent, keeping a food and symptom diary might reveal a pattern.

7. Talk to Your Doctor

If your bladder’s acting up more than expected, your doctor might tweak your dosage, switch your medication, or suggest ways to counteract the side effects.

There’s no harm in asking—it’s your body, and you deserve to feel in control.

When to Get It Checked

Most bladder changes from muscle relaxants settle once your body adjusts.

But if you’re dealing with any of the following, check in with a doctor:

• Leaks that don’t improve even after stopping the medication.
• Burning, pain, or a strong urine odour (could be an infection).
• You’re constantly struggling to empty your bladder completely.
• The leaks are seriously interfering with your life.
• You’re experiencing sudden, severe urinary retention (not being able to pee at all).

These may be signs of a bigger issue—and could point to a link between muscle relaxers and bladder issues that need medical attention.

Muscle relaxants are great for pain relief, but the bladder side effects? Not so much.

If you’re dealing with leaks, nighttime accidents, or frustrating urgency, know that you’re not alone. The connection between muscle relaxants and incontinence can be frustrating, but a few simple tweaks can make all the difference.

For now? Stay comfy, stay confident, and remember—you’re in control.