Anticonvulsants for chronic pain
Examples
Generic Name Brand Name carbamazepine Tegretol clonazepam Clonapam gabapentin Neurontin lamotrigine Lamictal oxcarbazepine Trileptal phenytoin Dilantin pregabalin Lyrica topiramate Topamax valproic acid Depakene How It Works
Experts do not know exactly how seizure medicines work to reduce chronic pain. They may block the flow of pain signals from the central nervous system.
Why It Is Used
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 post-herpetic neuralgia.
How Well It Works
Some seizure medicines 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 often used to treat chronic pain from trigeminal neuralgia (sudden facial pain).2
Pregabalin (Lyrica) is used to treat chronic pain from post-herpetic neuralgia and diabetic neuropathy. Studies show that pregabalin reduces chronic pain in these conditions.3 Pregabalin may help relieve chronic pain, sleep problems, and fatigue in fibromyalgia.4
Even though gabapentin and pregabalin are the only drugs that have been proven to help relieve some types of chronic pain, oxcarbazepine (Trileptal), lamotrigine (Lamictal), and topiramate (Topamax) may also be effective in reducing pain caused by diabetic neuropathy and post-herpetic 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
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 a seizure medicine. 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
Most seizure medicines are not yet approved by Health Canada for treating chronic pain. However, Health Canada has approved gabapentin to treat post-herpetic neuralgia. Gabapentin is also often used for other types of chronic pain.5
Health Canada has also approved pregabalin to treat chronic pain from post-herpetic neuralgia and diabetic neuropathy.3
Medicine will be started in low doses and then slowly increased until it effectively reduces your chronic pain.
Seizure medicines 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.
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| Author: | Shannon Erstad, MBA/MPH | Last Updated: May 28, 2007 |
| Medical Review: | Adam Husney, MD - Family Medicine Nancy Greenwald, MD - Physical Medicine and Rehabilitation Brian D. O'Brien, MD - Internal Medicine | |
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| Topic Contents | |
| Examples | |
| How It Works | |
| Why It Is Used | |
| How Well It Works | |
| Side Effects | |
| What To Think About | |
| References | |