Anticonvulsant Medications

What are anticonvulsants?

Anticonvulsants were invented relatively recently, about 100 years ago. Currently, on the pharmaceutical market a variety of drugs for spasms and cramps with different mechanisms of action and the ability to eliminate spasms of varying intensity and origin.

Cramps are involuntary muscle contractions. They can be in fully healthy people after a severe muscle strain, such as athletes, musicians, or sudden cooling in the water. Also, in healthy people, cramps and shudders may occur while falling asleep and during sleep.

But also spasms of different types can be symptoms of serious illnesses, such as epilepsy and others.

All the substances that are developed for anticonvulsant action inhibit neuronal excitability or excitation transmission in the central nervous system (CNS). However, they can also decrease the concentration of neurotransmitters in the extracellular space by affecting their reuptake and metabolism.

Effects on potential-dependent Na+ -channels and the GABAergic system are therapeutically important. Some anti-seizure medications impact more than one site at a time. Which antiepileptic meds should be used in a particular case depends on the type of seizure and the specific disease.

Types of seizure medications

Depending on the disease and its complexity, different types of anticonvulsants are used to treat seizures and spasms.

• AMPA receptor antagonist: Perampanel (Fycompa)
• Calcium channel modulators: Levetiracetam (Keppra, Keppra XL)
• Carbonic anhydrase inhibitor: Acetazolamide (Diamox), Carbamazepine (Tegretol), Eslicarbazepine (Aptiom)
• Carboxamides: Oxcarbazepine (Trileptal), Rufinamide (Banzel)
• GABA analogues: Gabapentin (Neurontin), Pregabalin (Lyrica), Progabide (Gabren), Vigabatrin (Sabril)
• GABA reuptake inhibitors: Tiagabine (Gabitril), Esogabine/Retigabine (Potiga)
• NMDA receptor blockers: Felbamate (Felbatol)
• Sodium channel modulators: Lacosamide (Vimpat), Lamotrigine (Lamictal), Phenytoin (Dilantin)
• Succinimides: Ethosuximide (Zarontin), Mesuximide (Celontin)
• Sulfamate-substituted monosaccharides: Topiramate (Topamax, Topamax ER, Qudexy XR)
• Sulfonamides: Zonisamide (Zonegran)
• Valproic acid: Divalproex Sodium (Depakote), Valproic acid (Depakine).
• Barbiturates: Phenobarbital, Primidone (Mysoline)
• Benzodiazepines: Clobazam (Onfi), Diazepam (Valium, Diastat), Lorazepam (Ativan), Clonazepam (Klonopin, Epitrile, Rivotril)

How does anti-seizure medication work?

A number of anti seizure meds, such as Carbamazepine, Oxcarbazepine, Valproic Acid, Phenytoin, and Lamotrigine, act predominantly on potential-dependent Na+ -channels. Valproate and Topiramate act in this way only partially by promoting the inactivation of Na+channels, the duration of the single action potential and its amplitude do not change.

The ability of neurons to produce bursts of high-frequency action potentials is reduced. Thus, the effect of these anticonvulsants is significantly more pronounced at high discharge frequencies than at low discharge frequencies.

Ca 2+ T-type channels play an important role in the development of absences. Ethosuximide and Mesuximide reduce Ca 2+ T-type currents in thalamocortical neurons. Depending on the membrane potential of the neuron, they inhibit the formation of low-threshold Ca 2+ spikes, which counteracts the development of spasms.

Benzodiazepines (Clobazam, Clonazepam, Diazepam, or Lorazepam) and barbiturates such as Phenobarbital are allosteric agonists of GABA receptors. They cause hyperpolarization of the cell membrane, which reduces cell excitability.

In addition, there are other mechanisms of action of anti seizure meds. Some affect the kinetics of neurotransmitters or neuromodulators, for example, Vigabatrin has an inhibitory effect on GABAergic transaminase and thus inhibits the breakdown of GABA in neurons and glial cells. Vigabatrin also increases the concentration of GABA in tissues by inhibiting the vesicular transport of GABA. Tiagabine blocks the uptake of GABA by neurons and glial cells. Because of this effect on the patient's nervous system, all of these drugs effectively eliminate seizures.

What are anticonvulsants used for?

The main disease that requires the use of anticonvulsant medications is epilepsy.

However, in addition to epilepsy there may be many other conditions that have nothing to do with it, but may be accompanied by seizures:

• Diseases of cerebral blood vessels and strokes are often the cause of the onset of acute symptomatic seizures.
• Traumatic brain injuries.
• Infectious diseases of the central nervous system (meningitis, encephalitis, HIV infection)
• Body intoxication
• Unwanted effects of the drug
• Hypoglycemia or electrolyte imbalances
• Drug or alcohol withdrawal seizures
• Alcohol overdose
• Intake of psychotropic drugs
• Liver failure
• Parkinson's Disease

In any case of severe or frequent seizures, antiepileptic meds are used.

Epilepsy medications: side effects

Since anticonvulsant medications affect the central nervous system, most cause some degree of drowsiness or dizziness, at least at the beginning of therapy.

In addition, most medicines for seizures can cause suicidal thoughts or actions and can cause or exacerbate depression.

Anticonvulsants have many possible side effects. Characteristic side effects include dizziness and severe fatigue. These symptoms occur with many anticonvulsants. Other side effects depend on the specific medication and can be caused by individual active ingredients.

What is the most common seizure medication?

The most commonly used medications in the epilepsy medications group are:

1. Valproic acid (Depakene, Depakote)

2. Lamotrigine

3. Topiramate

For partial seizures, the first drugs prescribed are:

1. Carbamazepine (Tegretol)

2. Phenytoin (Dilantin)

3. Oxcarbazepine (Trileptal)

Common medicines for seizures for children are Ethosuximide (Zarontin) and Phenobarbital in low doses for seizures in very young children.

It is important to use antispasmodic medications only after consulting a doctor and to dose them strictly according to the instructions or as directed by the doctor.