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Drug Info

Can you take gabapentin with Flexeril?

Flexeril and gabapentin can increase the risk of side effects, like drowsiness and swelling
Gerardo Sison medical writer headshot
By | Aug. 8, 2024
Two Rx medications: Can you take gabapentin with Flexeril?

Key takeaways

  • Combining Flexeril and gabapentin can increase the risk of serious side effects.

  • Both medications can slow down the central nervous system, causing drowsiness and dizziness.

  • Always consult your healthcare provider before mixing these drugs.

  • Some people, such as those with kidney or liver problems, should avoid taking these medications together.

In this article:

Flexeril and gabapentin are prescription drugs used to treat certain types of pain. Flexeril (cyclobenzaprine) is a muscle relaxant approved by the U.S. Food and Drug Administration (FDA) for short-term pain and discomfort from muscle spasms. Gabapentin, known by the brand name Neurontin, is an anticonvulsant that helps treat seizures and nerve pain. 

Flexeril or gabapentin medications may be prescribed when other analgesics or pain relievers are not effective. In some cases, a healthcare provider may prescribe Flexeril and gabapentin together for muscle and nerve pain. However, because they both can slow down the central nervous system (CNS), they may have overlapping side effects, several of which can be dangerous. 

Continue reading to learn more about the effects of taking Flexeril and gabapentin together. 

Can you take Flexeril with gabapentin?

It’s not generally recommended to take Flexeril with gabapentin due to possible drug interactions and their similar side effects. Cyclobenzaprine and gabapentin have different mechanisms of action and address pain in various ways. However, healthcare providers may sometimes prescribe these drugs together for off-label purposes, such as for fibromyalgia, restless leg syndrome (RLS), back pain, and other types of chronic pain. 

The typical dosage for both Flexeril and gabapentin is one tablet three times daily, but the dosage can vary depending on the individual. Always consult a healthcare professional before combining these medications. They will evaluate your medical history and potential risks or adjust dosages if necessary.

Who shouldn’t take Flexeril and gabapentin together?

For many people, combining Flexeril and gabapentin is not safe or appropriate. The following groups of people should use caution or avoid taking Flexeril and gabapentin.

People with kidney problems

If you have kidney problems, you should avoid taking Flexeril and gabapentin together. Your kidneys help remove these drugs from your body. If your kidneys aren’t working properly, the medications can accumulate, leading to dangerous concentrations and increased side effects.

People with liver problems 

People with liver problems should be cautious about taking Flexeril and gabapentin together. If the liver isn’t working well, the drugs can build up in the body, leading to increased side effects. 

Those with a known allergy to either medication

Anyone who has had an allergic reaction to Flexeril or gabapentin should not take these medications together. Allergic reactions can be serious, including symptoms like rash, itching, swelling, or difficulty breathing. Combining these drugs could increase the risk of a severe allergic reaction.

Those taking other CNS depressants

If you are taking other CNS depressants, such as opioids, benzodiazepines, and tricyclic antidepressants, you should avoid using Flexeril and gabapentin together. CNS depressants can slow down your brain activity, and combining them can lead to increased drowsiness or sedation. In severe cases, it could cause breathing problems or even be life-threatening.

Other people may also need to use caution when considering these medications together. Consult a healthcare provider to determine whether the combination is safe based on your needs and circumstances.

What happens if you take Flexeril and gabapentin together?

Flexeril and gabapentin share similar side effects. As some side effects may be serious, it’s important to use caution before taking Flexeril and gabapentin together. 

Drowsiness

Using Flexeril and gabapentin together can increase drowsiness. Both medications have sedative effects, which can make it hard to stay awake and do daily tasks, such as working or driving. You may need more sleep or naps throughout the day while using Flexeril and gabapentin.

Dizziness

Combining these two drugs increases the risk of dizziness. Dizziness can occur because Flexeril and gabapentin can lower blood pressure and affect balance. You might feel lightheaded when you stand up or move quickly. 

Swelling of the hands, legs, or feet

Both Flexeril and gabapentin can cause fluid retention in the body. When Flexeril and gabapentin are used together, swelling, also known as edema, may occur. Swelling can be uncomfortable and may indicate a more serious problem.

Nausea

Nausea is a common side effect when taking either medication alone. Therefore, many people may experience increased nausea after taking Flexeril and gabapentin together. Nausea may often lead to vomiting.

Fatigue

Extreme tiredness or fatigue is another potential effect of combining gabapentin and Flexeril. Because both medications depress the central nervous system, they can lower energy levels. You may feel exhausted even after a full night’s sleep, leading to mood changes.

Blurred vision

Blurred vision can occur when using Flexeril and gabapentin together. This side effect might make reading, watching TV, or using a computer difficult. It can also affect depth perception, making everyday activities more challenging.

Dry mouth

Both medications can cause dry mouth. This can lead to discomfort and difficulty swallowing or speaking.

Difficulty concentrating

Concentration difficulties are a common issue. The sedative effects of both drugs can make focusing on tasks challenging. This is especially concerning for activities that require mental alertness, such as driving or operating machinery. 

Low blood pressure

Mixing Flexeril and gabapentin can also cause low blood pressure, known as hypotension. This happens because both drugs can relax and widen blood vessels. Low blood pressure may lead to dizziness and fainting.

Headache

Headaches can be a side effect of taking Flexeril and gabapentin. Some people might experience mild to severe headaches, which can be persistent and may interfere with daily activities.

Serious side effects of mixing Flexeril and gabapentin

Combining Flexeril and gabapentin can lead to serious side effects. These include respiratory depression, low blood pressure, and serotonin syndrome, all of which can be life-threatening.

Respiratory depression

One of the most severe side effects of mixing Flexeril and gabapentin is respiratory depression. This condition occurs when breathing becomes slow and shallow. When taken together, Flexeril and gabapentin may increase the risk of severe breathing problems.

Respiratory depression can be particularly dangerous because it may lead to reduced oxygen levels in the blood. In the worst cases, it can cause respiratory failure, which requires immediate medical attention. This side effect is especially concerning for older adults or those with pre-existing respiratory conditions.

Serotonin syndrome

Another serious side effect of combining Flexeril and gabapentin is serotonin syndrome. This condition occurs when there is too much serotonin, a chemical in the brain. Both Flexeril and gabapentin are known to increase serotonin levels in the brain. Symptoms of serotonin syndrome may include agitation, hallucinations, rapid heart rate, and increased body temperature.

Serotonin syndrome is a medical emergency and can be life-threatening if not treated promptly. Immediate treatment usually involves stopping the medications and receiving supportive care in a hospital setting. 

How long should I wait to take Flexeril after taking gabapentin?

There is no specific waiting period recommended between taking these two medications, especially if you are prescribed both treatment options. The appropriate time to wait to take gabapentin after taking Flexeril depends on what works for you and what your healthcare provider recommends. 

In some cases, your healthcare provider may recommend taking them together in the evening. In other cases, they recommend staggering the doses by several hours to reduce the risk of side effects. If you want to eliminate the risk of increased side effects while taking both medications, you may want to wait until Flexeril is cleared from the body before taking gabapentin. 

Flexeril has a half-life of around 18 hours, which means it takes about 18 hours for half of the drug to be cleared from your system. It typically takes about four to five half-lives for a drug to be almost completely cleared from the body. Therefore, you may need to wait around 72 to 90 hours (or roughly three to four days) after taking the last dose of Flexeril before taking gabapentin. That way, you can make sure it’s mostly eliminated from your system.

Alternatives to taking Flexeril and gabapentin together

If you’re concerned about mixing Flexeril and gabapentin, there are other options to manage musculoskeletal and neuropathic pain. You might try physical therapy, which can help strengthen muscles and reduce pain without medication. 

Over-the-counter pain relievers like Advil (ibuprofen) or Tylenol (acetaminophen) may also be effective for mild to moderate pain. Sometimes, lifestyle changes like regular exercise, a balanced diet, and proper sleep can make a difference in managing symptoms. 

Bottom Line: Is it safe to mix Flexeril and gabapentin?

While some healthcare providers may recommend taking gabapentin and Flexeril together for certain conditions, it is not generally recommended due to the risk of overlapping side effects. Both medications can slow down your central nervous system, which can lead to serious adverse effects like increased drowsiness, dizziness, and trouble concentrating. 

Always consult your healthcare provider for medical advice before combining these drugs. There may be alternative treatments available that are safer and just as effective.