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Anticonvulsants / Anti-Seizure MedicationsInformation, Articles, Resources
What are Anticonvulsants? Anticonvulsants are diverse class of drugs indicated for the treatment of various types of seizures associated with seizure disorders such as epilepsy, a neurological dysfunction in which excessive surges of electrical energy are emitted in the brain, and other disorders. Anticonvulsant drugs are central nervous system depressants. These agents work by preventing the spread of abnormal electric discharges in the brain, although the exact mechanism of action is unknown. Anticonvulsant drugs are used singly or in combinations depending on the type and degree of seizure activity. The first anticonvulsant medications were bromides, introduced in 1850. In 1910, phenobarbital, which then was used to induce sleep, was found to have antiseizure activity and became the drug of choice for many years. In 1940, phenytoin was found to be an effective drug for the treatment of epilepsy. The last ten years of the 20th century were called in neuroscience "decade of the brain". This period has brought many new antiepileptic drugs: vigabatrin, lamotrigine, topiramate, tiagabine, gabapentin, oxcarbazepine, levetiracetam and zonisamide. Anticonvulsants classification
How do Anticonvulsants work? Anticonvulsants include a variety of agents, all capable of depressing abnormal neuronal discharges in the CNS that may result in seizures. They may work by preventing the spread of seizure activity, depressing the motor cortex, raising seizure threshold, or altering levels of neurotransmitters, depending on the group. Anticonvulsants for Bipolar Disorder At first, anticonvulsants were prescribed only for people who did not respond to lithium. Today, they are often prescribed alone, with lithium, or with an antipsychotic drug to control mania. Anticonvulsants used to treat bipolar disorder include:
Anticonvulsants for Pain management Anticonvulsants have been used in pain management since the 1960s. Anticonvulsants are effective for chronic pain syndromes like trigeminal neuralgia, diabetic neuropathy and for migraine prophylaxis 2. Neuropathic pain Use of newer anticonvulsants has marked a new era in the treatment of neuropathic pain. Gabapentin has the most clearly demonstrated analgesic effect for the treatment of neuropathic pain, specifically for treatment of painful diabetic neuropathy and postherpetic neuralgia. Lamotrigine has been reported to be effective in relieving pain from trigeminal neuralgia refractory to other treatments, and central post-stroke pain. Results from clinical trials of phenytoin are equivocal. Zonisamide's mechanisms of action suggest that it would be effective in controlling neuropathic pain symptoms. Other anticonvulsants, including lorazepam, valproate, topiramate, and tiagabine, have also been under investigation. Anecdotal experience provides support for studies with oxcarbazepine and levetiracetam for treating neuropathic pain 4. Acute pain Anticonvulsants for Migraine Anticonvulsant drugs seem to be useful for the prophylaxis of migraine. This might be explained by a variety of actions of these drugs in the central nervous system that are probably relevant to the pathophysiology of migraine. Anticonvulsants that have demonstrated their efficacy in clinical trials are divalproex sodium, topiramate, sodium valproate, gabapentin, carbamazepine. Topiramate (Topamax) is the only anticonvulsant approved by the FDA for migraine prophylaxis. Neither clonazepam nor lamotrigine was superior to placebo in the studies. 3 References
Medications
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