Anticonvulsants for chronic pain

Examples

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Brand Name	Chemical Name
Tegretol	carbamazepine

Brand Name	Chemical Name
Klonopin	clonazepam

Brand Name	Chemical Name
Neurontin	gabapentin

Brand Name	Chemical Name
Lamictal	lamotrigine

Brand Name	Chemical Name
Trileptal	oxcarbazepine

Brand Name	Chemical Name
Dilantin	phenytoin

Brand Name	Chemical Name
Lyrica	pregabalin

Brand Name	Chemical Name
Topamax	topiramate

Brand Name	Chemical Name
Depakote	valproic acid

Brand Name	Chemical Name
Zonegran	zonisamide

How It Works

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Experts do not know exactly how anticonvulsants work to reduce chronic pain. They may block the flow of pain signals from the central nervous system.

Why It Is Used

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Anticonvulsant drugs typically are used to control seizures in people who have epilepsy. These drugs may also be used to treat other painful conditions, such as postherpetic neuralgia and fibromyalgia.

How Well It Works

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Some anticonvulsant drugs may work better than others for certain conditions. For example, one small study showed lamotrigine to be effective in treating nerve-related pain related to some types of antiretroviral therapy in people with HIV.¹

Carbamazepine is approved by the U.S. Food and Drug Administration (FDA) to treat chronic pain from trigeminal neuralgia (sudden facial pain).²

Pregabalin (Lyrica) is approved by the FDA to treat chronic pain from postherpetic neuralgia and diabetic neuropathy. Studies show that pregabalin may reduce chronic pain in these conditions.³ It is also approved to treat fibromyalgia. Pregabalin may help relieve chronic pain, sleep problems, and fatigue in fibromyalgia.⁴

Even though gabapentin and pregabalin are the only drugs that have proved to help relieve some types of chronic pain, oxcarbazepine (Trileptal), lamotrigine (Lamictal), topiramate (Topamax), and zonisamide (Zonegran) may also be effective in reducing pain caused by diabetic neuropathy and postherpetic neuralgia. Long-term studies still need to be done to find out how well gabapentin, pregabalin, and other anticonvulsants help with chronic pain and to do comparisons with other types of medicines.

Side Effects

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Common but temporary side effects may include dizziness, drowsiness, and fatigue. Tell your doctor if you think you are having side effects, which may include:

• Headache.
• Confusion.
• Skin rash.
• Nausea, vomiting, loss of appetite, or abdominal pain.
• Weight gain or weight loss.
• Swollen feet.

Do not suddenly stop taking an anticonvulsant. Your health professional will slowly reduce the dosage of this medicine so that you won't develop withdrawal symptoms such as anxiety, nausea, pain, sweating, and insomnia.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

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Medicine will be started in low doses and then slowly increased until it effectively reduces your chronic pain.

Anticonvulsants are not safe for everyone. Be sure to tell your doctor about all medical conditions you have and other medicines you are taking to avoid side effects and complications.

Carbamazepine and lamotrigine may increase the chance of birth defects. If you are pregnant or thinking of getting pregnant, talk to your doctor before taking medicines.

Complete the new medication information form (PDF) (What is a PDF document?) to help you understand this medication.

References

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Citations

1. Simpson DM, et al. (2003). Lamotrigine for HIV-associated painful sensory neuropathies. A placebo-controlled trial. Neurology, 60(9): 1508–1514.

2. Drugs for pain (2004). Treatment Guidelines From the Medical Letter, 2(23): 47–54.

3. Pregabalin (Lyrica) for neuropathic pain and epilepsy (2005). Medical Letter on Drugs and Therapeutics, 47(1217): 75–76.

4. Crofford LJ, et al. (2005). Pregabalin for the treatment of fibromyalgia syndrome. Arthritis and Rheumatism, 52(4): 1264–1273.

Credits

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Author	Shannon Erstad, MBA/MPH
Editor	Kathleen M. Ariss, MS
Associate Editor	Pat Truman
Primary Medical Reviewer	Adam Husney, MD - Family Medicine
Primary Medical Reviewer	Kathleen Romito, MD - Family Medicine
Specialist Medical Reviewer	Nancy Greenwald, MD - Physical Medicine and Rehabilitation
Last Updated	February 22, 2007