Muscle relaxers are commonly prescribed to alleviate pain, stiffness, or spasms resulting from injuries, chronic conditions, or neurological disorders. While they can offer much needed relief, many people notice unexpected side effects including constipation. In this blog we will talk about how muscle relaxants work, why they might affect your digestive system, and what you can do to manage or prevent constipation while taking them.

Understanding Muscle Relaxers

Muscle relaxers, also known as muscle relaxants, are medications used to manage acute muscle pain and discomfort resulting from muscle spasms.

Muscle spasms are involuntary contractions that cause excessive strain in muscles and are linked with conditions such as neck pain and lower back pain.

Medications used as muscle relaxers can differ in their chemical structure and mechanism of action in the brain. Generally, muscle relaxers act as central nervous system depressants and prevent your nerves from sending pain signals to your brain.

The most commonly prescribed muscle relaxers are Carisoprodol, available under brand versions Pain O Soma 350mg tablets, among others and Cyclobenzaprine (Flexeril).

In 2017, approximately 4.2 million prescriptions for Soma tablets and 28.4 million prescriptions for Flexeril were dispensed in the US, according to data from IMS Health [1].

Can Taking Muscle Relaxers Cause Constipation?

Constipation is a digestive condition characterized by difficulty with passing stool or passing fewer than three stools a week [2].

If you have noticed changes in your bowel movements during treatment with a muscle relaxant, you may have thought: Do muscle relaxers cause constipation? The answer to this question is yes. Muscle relaxers can cause constipation as a side effect of the medication.

Why Do Muscle Relaxers Cause Constipation?

The following are some reasons why muscle relaxers can cause constipation [3].

Anticholinergic Effects

Some muscle relaxers have anticholinergic effects, especially cyclobenzaprine. Anticholinergics block the action of acetylcholine, a neurotransmitter that stimulates intestinal contractions. This leads to a slowing down of bowel movements, causing dry and hard stools.

Effects on the Central Nervous System

Muscle relaxers such as Soma pills (Carisoprodol) act by depressing the central nervous system to reduce muscle spasms. This can lead to overall slowed body functions, including bowel movements.

Water movement

The slower bowel movement gives the intestines more time to absorb water from the waste material. This can result in harder, drier stools that are difficult to pass, resulting in constipation.

Interaction with other drugs

Muscle relaxers are sometimes prescribed along with opioids, which are also constipating.

This combination can increase the risk of constipation.

How To Manage Muscle Relaxers Constipation?

The following natural remedies can help with constipation associated with the use of muscle relaxers [4].

Dietary changes: Foods rich in fibre such as dates, brown rice, fruits, vegetables, etc, swell the stool and support intestinal activity. It is recommended to increase the fiber dose gradually as additional discomfort (bloating, abdominal pain) may be expected initially until the intestines have adjusted.

Exercise: Engaging in physical activity can be highly beneficial for constipation as it helps promote bowel activity and regular bowel movements when incorporated into your daily routine.

Drink plenty of water: This is the most common solution to combat constipation associated with the use of muscle relaxers. If the intestinal contents are very solid and only move forward slowly, more water can help.

Probiotics: Consuming probiotics can help maintain a healthy balance of gut bacteria which in turn helps improve your digestion and regularity.

A study by Yuan He and colleagues suggests that treatment with probiotic compounds can improve intestinal mobility, improve bowel movement frequency, and effectively relieve constipation [5].

Other Side Effects Of Muscle Relaxers

Other than constipation some of the most commonly reported side effects of muscle relaxers are [6]:

Drowsiness

One common side effect associated with muscle relaxer use is drowsiness. This is because most muscle relaxers have a sedative effect on the central nervous system. The severity of drowsiness can also depend on your dosage strength.

Dizziness

Dizziness is another common side effect of a muscle relaxer. This can put you at risk of falls, especially in the older population. For this reason, experts strongly recommend avoiding muscle relaxers if you are 65 or older.

Dry mouth

Dry mouth is another commonly reported side effect of muscle relaxers that have anticholinergic effects. This means they block the action of acetylcholine, a chemical involved in muscle contractions.

Headache

The use of muscle relaxers can also lead to headaches. For example, headaches have been reported with Carisoprodol and metaxalone.

Nausea

A muscle relaxer can sometimes make you feel nauseous. Oftentimes, they can be taken on an empty stomach or with food. If taking the muscle relaxer on an empty stomach makes you nauseous, try taking it with a snack or meal.

When to See a Doctor

You should consult a doctor if you are suffering from constipation due to muscle relaxant use, if [7]:

• Have constipation that lasts more than a week.
• Take laxatives to have bowel movements.
• Have constipation every time you take the muscle relaxer.
• Experience other symptoms, such as changes in appetite, weight loss, and fatigue.

What your doctor might do:

• Adjust the dose or prescribe an alternative muscle relaxer
• Recommend an appropriate bowel regimen (e.g., fiber, laxatives, etc.).
• Rule out other causes, if any other than your use of a muscle relaxer.

Conclusion

Muscle relaxers such as Carisoprodol are highly effective in managing pain and muscle spasms. But just like other medications, they come with some unwanted side effects, and constipation is one of them. Constipation due to the use of muscle relaxers can result from several reasons. If you are suffering from constipation while taking any muscle relaxer, do not worry, as the symptoms will subside once you discontinue using the drug.

Always use this medication under the supervision of a medical provider to minimize the risk of side effects.