Can You Build Tolerance To Neurontin (Gabapentin)?

dtknoxville asked

Can you build a tolerance to gabapentin? I have been taking from 300-2,400 mg per day for over 2 years and don’t think it is working. I have been titrating down starting from 2,400 mg to 1,600 mg to 1,200 mg and currently 800 mg daily with no withdrawal symptoms at all. Should I continue to titrate down or can I simply stop at this point? Thank you very much!

Answer

Yes, it certainly is possible to experience tolerance to medications like Neurontin (gabapentin), which may necessitate dose increases to attain an appropriate level of pain relief.

However, it can sometimes be difficult to discern whether you are experiencing tolerance to the medication or if your pain symptoms (e.g. neuropathy) are simply getting worse. It is important to discuss your situation with your doctor so you can be properly evaluated.

Gabapentin Tolerance

Gabapentin has a fairly large effective dosage range (between 1,800 mg and 3,600 mg per day for neuropathic pain), and it is not uncommon to need to increase your dose over time to maintain the same level of pain relief.

There haven't been many studies in humans assessing tolerance and our knowledge of issues with tolerance are mostly from anecdotal reports. Nevertheless, animal studies have shown that gabapentin can lose efficacy over time.

In addition to tolerance problems, an issue with gabapentin is that bioavailability (i.e. rate and extent of absorption) decreases when higher doses are taken, which is why large doses are sometimes needed for effect. One study reported the following:

"The absolute bioavailability of gabapentin drops from 60% to 33% as the dosage increases from 900 to 3600 mg/day."

Do You Need To Taper Gabapentin?

If you have been on gabapentin for an extended period of time, it is generally recommended to taper your dose slowly if you are discontinuing the medication to avoid rebound symptoms or other withdrawal reactions.

Potential withdrawal symptoms of gabapentin include:

• Anxiety
• Insomnia
• Nausea
• Sweating
• Pain
• Irritability
• Agitation
• Flu-like symptoms
• Mental status changes
• Seizures

There is no single recommended way to taper gabapentin, but the prescribing information for the drug recommends the following:

"If Neurontin [gabapentin] dose is reduced, discontinued or substituted with an alternative medication, this should be done gradually over a minimum of 1 week (a longer period may be needed at the discretion of the prescriber)."

Some sources recommend an even longer taper schedule (weeks to months) if you were taking the medication for seizure control as rebound seizures can pose a serious medical risk.

Not everyone will experience withdrawal symptoms and not everyone will need to taper gabapentin. Everyone's medical situation is unique. Be sure to speak with your doctor regarding an appropriate tapering schedule for you.