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Fibromyalgia Basics

Gabapentin vs. Pregabalin
What’s the Difference?

Home | Medications

Photo of person questioning the difference of gabapentin versus pregabalin for treating fibromyalgia.

Gabapentin and pregabalin both work to increase the amount of GABA (a pain-fighting transmitter) in your central nervous system. These two medications are in the same drug class. They are gabapentinoids or more generally called anticonvulsants. However, there are differences between them. For starters, gabapentin has been on the market ten years longer, so it’s the cheaper option. On the other hand, pregabalin is FDA-approved for treating fibromyalgia pain, while gabapentin is not. Naturally, doctors prefer to prescribe medications approved for a specific condition, but other factors warrant consideration.

If your physician prescribes pregabalin, it will cost you more than the same dose-equivalent script for gabapentin. How much more you pay depends on your insurance. Most insurers place pregabalin in a higher tier or cost bracket than gabapentin, so you end up paying more for it.

Given the added expense, is pregabalin worth it? To confidently answer this question, a head-to-head trial comparing the two drugs is needed. Unfortunately, this data is not available. However, an analysis of the trial data for each drug tested against a placebo (sugar pill) does exist.1 The next section summarizes the results to help you decide if pregabalin or gabapentin is best for your fibromyalgia.

Drug Comparisons

If you wonder why pregabalin has never been tested against gabapentin, the answer is simple. Both drugs are made by the same company, Pfizer, and there’s no financial incentive to show which drug is better. So, what does the data reveal about efficacy and side effects of the two drugs to treat fibromyalgia?

Only one quality trial in fibromyalgia patients comparing gabapentin to placebo exists. The daily dose was 2400 mg/day (equivalent to 300-450 mg/day pregabalin). The trial lasted three months and involved only 150 patents. On the other hand, data exists for five pregabalin trials involving 500 to 700 patients each. Clearly, the information is a bit less certain for gabapentin than pregabalin. Putting these factors aside, below are the key findings:

  • For every five fibromyalgia patients treated with gabapentin, only one will achieve a 30 percent pain reduction. This number needed to treat using pregabalin is eight for just one person to reap benefits.
  • The researchers state that successful drugs effectively treat one out of every two to four patients. Using these criteria, the researchers classified both drugs as “unimpressive.” Nevertheless, gabapentin appears slightly more effective for treating fibromyalgia pain.
  • Dizziness, headaches, sleepiness, and edema (fluid retention) are commonly reported side effects for both
  • The most frequently reported side effect is dizziness in patients taking pregabalin (38 percent). Another troubling side effect is weight gain (11 percent).
  • The most frequently reported side effect is headache for gabapentin (27 percent). Nausea (21 percent) is another frequent side effect.

Gabapentin appears more helpful for treating fibromyalgia, but the side effects of the two drugs may be your deciding factor. On the other hand, there is more data on pregabalin and how to minimize the side effects. The evidence for gabapentin is very limited.

Pregabalin More Regulated

The Drug Enforcement Agency (DEA) decided to place more regulations on pregabalin by making it a Schedule V (or 5) medication. Gabapentin is not regulated by the DEA, but seven states in the U.S. treat it as a Schedule V medication. These states are AL, KY, MI, ND, TN, VA, and WV.

Your healthcare provider must have a current DEA license to prescribe pregabalin. In addition, your doctor will require annual visits (at a minimum). Other restrictions based on your state’s laws may apply

Overall, Schedule V carries the lowest potential for abuse of the drugs that are scheduled by the DEA. But why would pregabalin be regulated by the DEA, while gabapentin is not, given that they are in the same class of medications? The answer has to do with the timing of the FDA trials.

Gabapentin was approved in the 1990s when the FDA imposed fewer testing requirements. When pregabalin was up for approval, testing the medication in substance abusers was required. The drug made the addicts less anxious compared to healthy people by a small margin. As a result, the DEA made it a Schedule V drug.

The mild anti-anxiety property of pregabalin is a favorable effect for drugs used to treat people with persistent pain. However, more information about pregabalin has accumulated over the years and the drug shows increased rates of addiction and dependence.2 These undesirable effects may be less with gabapentin, but it’s why several states placed additional regulatory scrutiny on the drug.

Will your doctor deny writing a script for pregabalin because of a Schedule V rating? Probably not. But beware that insurance companies may regulate your prescription refill requests in a more restrictive manner. This can make a script for pregabalin more of a hassle.

Gabapentin for Fibromyalgia

Table showing key points on using gabapentin for fibromyalgia pain.

The scientific support for using gabapentin in fibromyalgia patients is limited. In fact, it’s unclear if the benefits outweigh the side effects.3 These days, everyone is looking for an alternative to opioids for treating pain. Indeed, this sentiment is expressed in a recent report on gabapentinoids: “We are all looking for the magic pill.”4  Gabapentin is not the magic pill, but it may be worth a try.

The standard daily dose of gabapentin is 1,200 mg to 2,400 mg for treating fibromyalgia. This is eight times the dose of pregabalin because gabapentin is not as well absorbed into the body. Therefore, you must take more of it. Another point to consider is how often you need to take the medication. Generally, gabapentin is prescribed three times a day but varies depending on side effects.

It may take up to three weeks to reach the target dose. Due to the sedating side effect, which may wear off with use, gabapentin is started with an evening dose. In fact, taking the brunt of the drug with dinner and at bedtime helps with sleep. It also minimizes the other side effects of dizziness, nausea, and edema (fluid retention in hand and feet).

If you check our article on pregabalin, the advice from the treatment experts is also useful for gabapentin. Just keep in mind that your target dose is between 1,200 mg/day and 2,400 mg/day. So, a typical daily dosing may be 300-600 mg in the morning, at noon, at dinner, and again at bedtime.  

If you need to go off gabapentin, do it slowly to avoid a symptom flare up due to withdrawals. Also, both drugs (gabapentin and pregabalin) are metabolized by your kidneys. If you have serious renal impairment, talk to your kidney specialist before trying either drug.

Fibro Patient Resources

Most patients take more than one medication and use a variety of alternative approaches to reign in their fibromyalgia symptoms. Check out the following pages for help:

Medications | Nondrug Treatments |  Muscle Pain Relief  |  Movement Therapies  |  Diet & Nutrition

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References

  1. Siler AC, et al. J Pain 12(4):407-415, 2011. Free Report
  2. McNeilag AG, et al. BMJ Open 13:e073770, 2023. Free Report
  3. Cooper TE, et al. Cochrane Database Syst Rev 1(1):CD012188, 2017. Free Report
  4. McNeilage AG, et al. Int J Drug Policy 119:104112, 2023. Free Report