Anticonvulsants: Seizure Preventers and Mood Stabilizers

Anticonvulsants are a large group of medications used in prevention of the occurrence of epileptic seizures, also known as anti-epileptics. Although they’ve initially been used only to treat epileptic episodes, today they are also seen as mood stabilizers. It has been proven that anticonvulsants can help in treatment of the bipolar disorder.

An epileptic attack is a consequence of rapid and excessive firing of neurons that start a seizure. Anticonvulsants prevent this, and thereby contain the spread of the seizure within the brain, and possible brain damage. There are several possible mechanisms of action: some of them block Sodium (Na+) channels and Calcium (Ca2+) channels, while some block AMPA receptors or NMDA receptors. Some anticonvulsants inhibit the metabolism of GABA or increase its release.

Anticonvulsants most commonly used are barbiturates and benzodiazepines. Instead of using only one drug, people often take two or more anticonvulsant medications to prevent seizures;  possible interaction may cause several health problems.

 

 

Types of seizures treated with anticonvulsants

A seizure is a synchronized depolarization of brain cells. It affects parts of the brain, or sometimes the whole cortex. The seizure mechanism is the only way the brain can defend itself against outer influences!

There are four different seizure types, each with its own characteristic symptoms:

•         Petit Mal
•         Grand Mal (Generalized Tonic Clonic)
•         Single Focal
•         Partial Complex

Petit mal

•         minimal or no movements
•         an appearance like a blank stare
•         brief sudden loss of awareness or conscious activity  
•         recurring many times throughout childhood
•         decreased learning

Grand mal

•         generalized, violent muscle contractions  
•         patient emitting a sudden cry
•         Breathing stopping temporarily
•         loss of consciousness
•         weakness
•         stupor
•         headache
•         confusion
•         incontinence of urine
•         tongue or cheek biting

Single focal

•         muscle contractions of a specific body part
•         abnormal sensations  
•         nausea
•         sweating
•         skin flushing
•         dilated pupils
•         other focal (localized) symptoms

Partial complex

•         automatism
•         nausea
•         sweating
•         skin flushing
•         dilated pupils
•         loss of consciousness
•         changes in personality  

Most commonly used anticonvulsants and their side effects:

Drug name	Drug class/structure	Common side effects
phenytoin (Dilantin®)	Hydantoin	Dizziness, drowsiness, confusion, Ataxia, nausea, gingival hyperplasia, megaloblastic anemia, leukopenia
carbamazepine (Epitol®, Tegretol®)	Tricyclic	Sedation, dizziness, fatigue, confusion, ataxia, nausea, blood, dyscrasias, hepatotoxicity
valproic acid (Depakene®, Depakote®)	Carboxylic acid	Anorexia, diarrhea, nausea, drowsiness, ataxia, irritability, confusion, headache, leucopenia, thrombocytopenia, hepatotoxicity, prolonged bleeding time
ethosuximide (Zarontin®)	Succinimide	Ataxia , sedation, dizziness, hallucinations, behavioral changes, headache, Stevens-Johnson syndrome, systemic lupus, erythematosus, nausea, anorexia
clonazepam (Klonopin®)	Benzodiazepine	Tachycardia, drowsiness, fatigue, anxiety, ataxia, headache, dizziness, blurred vision, xerostomia
primidone (Mysoline®)	Barbiturate derivative	Drowsiness, vertigo, ataxia, behavioral changes, headache, nausea
Phenobarbital (Barbita®, Luminal®, Solfoton®)	Barbiturate	Dizziness, lightheadedness, sedation, ataxia, impaired judgment, skin rashes

Anticonvulsants as mood stabilizers

Mood stabilizers are medications used to treat mood disorders, especially bipolar disorder. They are used to treat the depressive part of this disorder (which also has a manic part, of course.) Anticonvulsants also used as mood stabilizers include valproic acid and carbamazepine. There are several theories regarding their mechanism of function, and the most probable is the one that claims they regulate the glutamate excitatory neurotransmission and GABA inhibitory neurotransmission. Studies have shown that they also have certain intracellular effects such as modulation of the activity of enzymes, ions, arachidonic acid turnover, G-protein coupled receptors, and intracellular pathways involved in synaptic plasticity and neuroprotection. 
 

Common anticonvulsants and their side-effects

There are some side effects common to all anticonvulsants. Some of these also can be applied to mood stabilizers of other classes.
 
•         Lethargy and photosensitivity
 Anticonvulsants may lead to lethargy and photosensitivity; if you want to sleep more, you simply must avoid prolonged exposure to strong sunlight, This side effect is practically unavoidable, since it’s due to the specific nature of anticonvulsants. They are made to slow down the brain’s impulse to fight mania or prevent seizures to happen; in doing so, they also wind up slowing down the patient’s metabolism. 

•         Weight gain
A number of patients have reported weight gain, but only with four of the FDA-approved mood stabilizers: Lithium®, Depakote®, Seroquel® (quetiapine) , and Zyprexa® (olanzapine).

•         Impact on memory and cognitive processes
Most anticonvulsants will impact a patient’s memory and cognitive processes, but only at first. After a while, this side effect simply stops. This has been reported by a great majority of patients.

•         Changes in dreaming patterns
There is no exact rule about the extent of possible changes, but a patient’s dreams do change in some ways.  Some report positive changes, and some experience nightmares. 

•         Hormonal changes
Almost all anticonvulsants mess around with our hormones, both female and male. Women can expect menstrual cycles to be disrupted, for example. If a patient is taking birth control pills, she must discuss the interaction of these medications with a specialist. Anticonvulsants such as Tegretol® (carbamazepine USP) and valproates are believed to interfere with a normal metabolism of testosterone.

Interactions with Dietary Supplements

 
•         Biotin: Several controlled studies have shown that anticonvulsant treatment decreases blood levels of a vitamin called biotin. This can leave a great impact, especially on children; it can cause withdrawn behavior and a delay in mental development. Adults experience a loss of appetite, feelings of discomfort or uneasiness, mental depression, or hallucinations. 
•         Calcium: Patients who are on long-term multiple anticonvulsant therapy may develop a condition called hypocalcaemia, characterized by below-normal blood levels of calcium. 
•         Vitamin A: Anticonvulsant drugs can occasionally cause birth defects when taken by pregnant women, possibly due to low blood levels of vitamin A. 
•         Vitamin B6: Anticonvulsive medications may also cause reduced blood levels of vitamin B6. This condition has been associated with atherosclerosis and some other symptoms such as dizziness, fatigue, and mental depression.
•         Vitamin B12: Some anticonvulsants can even cause anemia. Such effects might be associated with a vitamin B12 deficiency. 
•         Vitamin K: Babies born to women taking anticonvulsant drugs tend to have low blood levels of vitamin K. This vitamin is important in blood clotting, so the main symptom is usually the infant’s bleeding.