Concerns Taking Cyclobenazprine, Gabapentin And Oxcarbazepine Together

In our latest question and answer, the pharmacist discusses the safety of taking cyclobenzaprine, gabapentin and oxcarbazepine together.

Concerns Taking Cyclobenazprine, Gabapentin And Oxcarbazepine Together
Jul 02, 2020

Stephanie asked

I take gabapentin and Trileptal due to a rare neurological condition: glossopharyngeal neuralgia. I hurt my back and dr has prescribed Flexeril...wondering what can this cocktail can do to me?

At a glance

  • Taking all three medications is probably appropriate.
  • Cyclobenzaprine, gabapentin, and oxcarbazepine all commonly cause dizziness and drowsiness.
  • This combination of medications increases your risk of shared side effects.


Thank you for your question Stephanie.

First off, Flexeril (or its generic name cyclobenzaprine) is a skeletal muscle relaxant that your doctor is prescribing to help your back pain or spasms. This medication can cause several side effects including drowsiness, fatigue, dizziness, and confusion.

Neurontin (or under the generic, gabapentin) is usually used to help treat neuropathic pain (nerve pain) or a number of other conditions. It can cause similar side effects to cyclobenzaprine including impaired coordination, dizziness, drowsiness, and fatigue.

Trileptal (or by the generic name of oxcarbazepine) can also be used to treat neuropathic pain. It shares some common side effects to cyclobenzaprine and gabapentin including dizziness, drowsiness, and impaired coordination. Oxcarbazepine is not known to cause CNS depression. 

Most commonly, taking these medications together will cause some additional drowsiness or dizziness. I would probably expect this to happen. Much more rarely, these medications can cause CNS depression.

Severe CNS depression is rare when taking these medications at their normal doses. Signs of severe CNS depression include reduced heart rate, low breathing rate, confusion, or memory loss. If you experience a reduced heart rate (less than 50-60 beats per minute) or a greatly reduced breathing rate; this is an emergency and you should call 911 or have someone take you to the nearest emergency room.

If you find that you are more confused or experiencing memory loss, I’d recommend contacting the physician and seeing if they could prescribe something in place of the cyclobenzaprine. I would also recommend that you avoid consuming alcohol while taking these medications. 

When starting cyclobenzaprine, you should be cautious about driving or operating anything that requires your full attention until you know how the medication affects you. Cyclobenzaprine is typically only dosed as needed. Assuming that your physician wrote your prescription this way, only take this medication when you feel you need it. By taking it only as needed, you can avoid some of the added drowsiness this medication can cause. Another way to avoid excessive drowsiness is to take cyclobenzaprine at night until you know how it affects you. Taking it before bedtime can prevent excessive daytime drowsiness.

Thank you for your question and feel free to write us back in the future.

Research for this answer was completed with input from Pharm D. candidate Gwynn Smith

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