Anticonvulsant medications are drugs that are used to treat epileptic seizures. Epileptic seizures occur when signals in the brain fire together more frequently than usual. While several factors can increase the risk of seizures, scientists do not yet know the exact biological cause of seizures. Anticonvulsant drugs decrease the signals in the brain that increase the risk of seizures and also help reduce the frequency and severity of seizures.
What are Anticonvulsants?
People may wonder, “What are anticonvulsant drugs and what are anticonvulsants useful in treating?” Anticonvulsants are known for treating epileptic seizures. They have, however, also been found to be useful in treating certain mental conditions such as mood disorders. How anticonvulsants help mental health conditions are not yet fully understood, but the function is likely related to how anticonvulsants decrease neurological signals to parts of the brain.
Anticonvulsants have several uses and conditions that they can help treat besides the different types of seizures that they were originally developed for. Different anticonvulsants can be used to treat different conditions, and not all anticonvulsants act the same. The conditions that anticonvulsants may treat in addition to seizures include:
- Headaches, especially migraines and cluster headaches
- Nerve pain
- Restless leg syndrome
- Bipolar disorder
- Drug withdrawal, especially from cocaine.
The use of anticonvulsants for these conditions should only be done with the supervision of a doctor. People should not take anticonvulsants for any of these conditions without first consulting a doctor.
Background & History
The history of using anticonvulsants for seizures started in 1857 when scientist Charles Locock used potassium bromide to treat seizure-type activity in 15 young women. Since then, the use of anticonvulsant medications for epilepsy has greatly improved. In 1938, the drug phenytoin was first developed. Phenytoin, known by its brand name Dilantin, was the first true anticonvulsant medication invented. Since then, multiple anticonvulsant medications have been discovered and cleared for clinical use, with about 20 types of anticonvulsants commonly used in the United States today.
In 1975, it was noted that during the experimental treatment of epilepsy using anticonvulsants, people would often report an elevation and improvement in their mood. In 1995, valproic acid was approved by the Food and Drug Administration (FDA) for use in bipolar disorder, especially in the manic phase. In 1996, a study found that the anticonvulsant carbamazepine was useful for treating the mania that occurred with bipolar disorder. Carbamazepine was soon after recommended as a possible medication for long-term mood stabilization in those with bipolar disorder.
Since then, there have been multiple mental health uses discovered for different anticonvulsants, including the treatment of bipolar disorder, generalized anxiety disorder, post-traumatic stress disorder (PTSD), major depressive disorder and schizophrenia.
Use in Treating Mental Illness
There have been many mental health disorders which anticonvulsants have been found to be effective in treating. A large study of multiple mental health uses for anticonvulsants found evidence for their use in treating multiple diseases. These treatment usages included treating:
- Bipolar disorder: The use of anticonvulsants for bipolar disorder was the first mental health-related use of anticonvulsants. Anticonvulsant medications that are commonly used for bipolar disorder include carbamazepine, valproic acid, lamotrigine, phenytoin, and gabapentin. These medications are primarily used to treat mania as anticonvulsant mood stabilizers, but can sometimes be used in the long-term management and stabilization of bipolar disorder.
- Anxiety disorders: Multiple anticonvulsants were successfully used in treating anxiety disorders. Pregabalin was successfully used for treating generalized anxiety disorder (GAD). PTSD can also be treated using lamotrigine and topiramate.
- Depression: Major depressive disorder can be treated with lamotrigine and topiramate. These anticonvulsants were found to be effective in helping reduce the symptoms of depression.
- Schizophrenia: The use of multiple types of anticonvulsants for treating schizophrenia was studied. The anticonvulsants that were found to be effective have been topiramate, carbamazepine, valproic acid, and lamotrigine.
While these medications were found to be helpful in treating these mental health conditions, everyone’s circumstances are different. People considering using an anticonvulsant for a particular condition or situation should consult with their doctor regarding the risks and benefits of using that medication.
How Do Anticonvulsants Work?
People considering using anticonvulsants often wonder, “How do anticonvulsant drugs work?” For some anticonvulsants, the exact way that they work is unknown, but most anticonvulsant medications work by acting on sodium channels in brain cells or by interacting with a receptor in the brain called gamma-Aminobutyric acid (GABA) receptors. Sodium is an important chemical used in the transmission of nerve signals. The flow of sodium into and out of brain cells is one of the key factors in determining if brain cells send nerve impulses and how fast those nerve impulses travel. Many anticonvulsant medications alter how fast sodium transfers in and out of brain cells, causing nerve signals to slow down and lowering the risk of seizures.
GABA receptors play an important role in brain activity, and activating these receptors causes sedation and slows nerve signals. Some anticonvulsants work by activating these receptors and slowing nerve signals, causing a decrease in the probability of seizures occurring.
List of Anticonvulsants
There are several types of anticonvulsants, with new anticonvulsants being developed all the time. The list of anticonvulsants given may vary from source to source, as some will consider drugs that were historically used or drugs that are more obscure and not fully accepted by science. Other lists may focus only on more modern and prevalent anticonvulsant medications. While lists may differ, some common anticonvulsant medications include:
- Carbamazepine (Most common brand name Tegretol)
- Gabapentin (Most common brand name Neurontin)
- Lamotrigine (Most common brand name Lamictal)
- Oxcarbazepine (Most common brand name Trileptal)
- Topiramate (Most common brand name Topamax)
- Valproic Acid, also called valproate (Most common brand name Depakene)
- Pregabalin (Most common brand name Lyrica)
- Phenytoin (Most common brand name Dilantin)
- Levetiracetam (Most common brand name Keppra)
While this list is not absolute, these are the most commonly used anticonvulsant medications available on the market in the United States.
Side Effects of Anticonvulsants
There are anticonvulsant side effects that could be experienced while taking these types of medications. Most of the time these side effects are mild and do not last for long. Some people do not experience any significant side effects while taking anticonvulsant medications. Those who do experience side effects typically find that they quickly pass and are just a minor inconvenience. Minor side effects that may be experienced with anticonvulsant use include:
- Abdominal cramps
- Blurred vision
If these side effects occur, they typically will be present for the first two or three weeks and then will resolve on their own.
As with any type of drug, there are some very serious side-effects that may be experienced by using anticonvulsant drugs. These side effects are extremely rare, but are still a possibility and must be considered. These side effects include:
- Decreased function of the pancreas
- Decreased number of white blood cells (cells used to fight infection)
- Decreased number of platelets (cells used to control bleeding)
- Aplastic anemia (severe damage to bone marrow that affects the production of red blood cells)
- Liver failure
If you are taking an anticonvulsant and believe that you may be experiencing any of these side effects, you should immediately seek medical help and be evaluated by a doctor.
In addition to the side effects that may occur when starting anticonvulsants, there are some potential long-term effects of anticonvulsants. One study found that some of these long-term risks included:
- Finger tremors at rest
- Diminished or decreased reflexes.
- Altered gait
- Joint pain
- Double vision
- Involuntary eye movements
- Inflammation of the gums
- Hirsutism (Male-pattern hair growth in females)
- Inflammation of the skin
While not everyone who takes anticonvulsants long-term will experience these symptoms, the risk of having these side effects does increase based on the length of time these medications are used and how much is used. There is also some evidence suggesting that with the use of an anticonvulsant, suicide risk may double.
Anticonvulsant drug interactions are common. Anticonvulsant medications may change how other drugs work in the body and interact with one another. It would be impossible to list all the different pairs of anticonvulsant drugs and other medications and detail every interaction between them. Some combinations, for example, may lower blood pressure, while others may raise it. Given the wide variety of interactions that could occur and the different circumstances of each individual, someone who is on an anticonvulsant medication should check with their doctor that the medication does not interfere with any other medications or recreational substances (including alcohol) that they are using.
One known type of medications that may be affected by anticonvulsants is birth control medications. Anticonvulsants can affect the way that the body processes birth control medication and may make it ineffective. This factor increases the risk of pregnancy while taking anticonvulsants, and those who are using anticonvulsants and birth control medications together may need to explore other methods of birth control while using anticonvulsants.
Stopping Anticonvulsant Use
People who are taking anticonvulsants should not stop using them suddenly or reduce the dose that they are using without talking to a doctor. People may think that it is okay to skip a dose every once in a while, or to stop using anticonvulsants altogether if they are having side effects or are not getting the therapeutic effect they had hoped for.
People may also run out of medication, or put money that should be used for anticonvulsant medications towards other things. While it may sometimes seem difficult to continually use anticonvulsants as prescribed, following the recommended schedule for anticonvulsant medications is very important.
Stopping anticonvulsants suddenly is very dangerous. Anticonvulsant medications suppress nerve signals in the brain and help balance electrical activity within the brain. When anticonvulsant medications are suddenly no longer in the bloodstream, the brain signals that were being suppressed will not only return to their normal level but will initially return stronger than they previously were. This process makes the signals that initially created seizures in the first place stronger than they were while they were causing seizures. Suddenly stopping anticonvulsant medications can lead to a much higher risk of experiencing seizures. This risk is true even for those who did not initially have seizures but were using anticonvulsants to treat another condition. Stopping anticonvulsants suddenly will increase brain signals that could lead to seizures, even if seizures were not previously experienced.
Taking Anticonvulsants While Pregnant
The use of anticonvulsants while pregnant is complex. Many women who are taking anticonvulsants do so to prevent seizures. These medications provide balance to the neurological signals in the brain and help to prevent further seizures from being experienced. Due to the nature of the medicines, stopping them suddenly will lead to more of a risk of seizures than would have existed without taking them in the first place.
It is unhealthy to suddenly stop these medications, and changes to anticonvulsant medications should be made slowly, making it difficult to adjust them once a pregnancy has started. While stopping these medications is often difficult and not recommended, there is a link between certain anticonvulsants and birth defects.
The best way to adjust anticonvulsant medications with pregnancy is to adjust them before the pregnancy begins and to avoid getting pregnant until adjusted. This adjustment may involve switching methods of birth control, as anticonvulsants can interfere with some birth control medications. The preferred method of changing anticonvulsant medications is to attempt to change to one medication that will control seizure activity and attempt to avoid combining medication. Treatment of symptoms will focus on finding the best medication at the lowest effective dose.
Research also suggests that supplementing the diet with folate is helpful when taking an anticonvulsant while pregnant. The best anticonvulsant medications to take during pregnancy seem to be lamotrigine, clonazepam, and levetiracetam — there is not much information regarding gabapentin. Phenytoin and phenobarbitone are suspected of leading to the development problems for the fetus.
Topiramate and carbamazepine are known to cause developmental problems to the fetus but may be less likely to be a problem in lower doses. Valproate is known to cause developmental problems to the fetus, even in lower doses, and should be absolutely avoided if possible during pregnancy. These are general guidelines, and someone who has questions about the medications they are on and how they could affect pregnancy should consult with their doctor. Under no circumstances should anticonvulsant medication use be reduced or stopped without a doctor’s permission, as this could lead to a severe risk of seizures and other complications.
What to Do In Case of Overdose
Anticonvulsant toxicity is experienced when there is too much of an anticonvulsant drug in the bloodstream. This occurrence may be more likely if multiple anticonvulsants are used simultaneously, as the drugs can interact with each other and increase each other’s strength and potency. Anticonvulsant overdose symptoms are not normally dangerous unless a large amount is taken. Symptoms of mild or moderate overdoses on anticonvulsants include:
- Dizziness or lightheadedness
- Feeling drowsy or tired
- Blurred or double vision
- Poor coordination or balance
- Unsteady walking
- Stomach pain
More severe cases of overdose may cause coma, decreased breathing and death. The symptoms of an overdose are different for each medication, and someone who believes they have had a mild overdose should contact Poison Control to determine if any treatment is needed. Anyone who suspects a moderate to severe overdose should immediately go to the nearest emergency room or call 911, as more severe overdoses on anticonvulsant medications can lead to life-threatening situations.
Get More Information on Anticonvulsants
You can find more information on anticonvulsants by studying resources about individual anticonvulsants.
- The Epilepsy Foundation has several resources about seizures and the medications used to treat them.
- Medscape is a good resource for learning information about medications, including their individual side effects, doses, common uses and miscellaneous information particular to medications.
- Merck Manuals is another reliable, scientific resource for information about medications.
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Ko, David Y. “Epilepsy and Seizures Medication.” Medscape, May 30, 2019. Accessed June 6, 2019.
Adamolekun, B. “Seizure Disorders.” Merck Manuals, November 2018. Accessed June 6, 2019.
Brodie, Martin J. “Antiepileptic Drug Therapy the Story so Far.” Seizure, December 2010. Accessed June 6, 2019.
Post, R. M. “The Place of Anticonvulsant Therapy in Bipolar Illness.” Psychopharmacology, November 1996. Accessed June 6, 2019.
Grunze, Heinz C. R. “The Effectiveness of Anticonvulsants in Psychiatric Disorders.” Dialogues in Clinical Neuroscience. March 2008. Accessed June 6, 2019.
Medscape. “Carbamazepine (Rx).” March 2019. Accessed June 6, 2019.
Medscape. “Gabapentin (Rx).” October 2018. Accessed June 6, 2019.
Medscape. “Lamotrigine (Rx).” February 2019. Accessed June 6, 2019.
Medscape. “Oxcarbazepine (Rx).” October 2018. Accessed June 6, 2019.
Medscape. “Topiramate (Rx).” October 2018. Accessed June 6, 2019.
Medscape. “Valproic Acid (Rx).” October 2018. Accessed June 6, 2019.
Medscape. “Pregabalin (Rx).” October 2018. Accessed June 6, 2019.
Medscape. “Phenytoin (Rx).” October 2018. Accessed June 6, 2019.
Medscape. “Levetiracetam (Rx).” October 2018. Accessed June 6, 2019.
Schachter, Steven C., Shafer, Patricia O., & Sirven, Joseph I. “Side Effects.” Epilepsy Foundation, March 19, 2014. Accessed June 6, 2019.
Nakazawa, Y. & Ohkawa, T. “Study of the Side Effects of Long-Term Anticonvulsant Treatment.” Folia Psychiatrica et Neurologica Japonica, 1980. Accessed June 6, 2019.
Sirven, Joseph I. & Shafer, Patricia O. “Drug Interactions.” Epilepsy Foundation, March 19, 2014. Accessed June 6, 2019.
Gedzelman, Evan & Meador, Kimford J. “Antiepileptic drugs in women with epilepsy during pregnancy.” April 2012. Accessed June 6, 2019.
Eadie, Mervyn J. “Antiepileptic Drug Safety in Pregnancy: Possible Dangers for the Pregnant Woman and her Foetus.” January 15, 2016. Accessed June 6, 2019.