Complex partial seizure drugs used

Benzodiazepines and barbiturates are used as anticonvulsant drugs in the treatment of epilepsy. Epilepsy, a medical disorder characterized by recurrent seizures, has many different forms. The four most common seizure types are generalized tonic-clonic seizures (old name grand mal seizures), generalized absence seizures (petit mal seizures), complex partial seizures (psychomotor or temporal lobe seizures), and simple partial seizures (focal seizures). 

All the following drugs are useful in treating complex partial seizures EXCEPT ... 

Mephenytoin is demethylated to 5-ethyl-5-phenylhydantoin (Nirvanol), which is an active anticonvulsant. Mephenytoin binds to plasma protein to the extent of 40%, with an elimination half-life of 7 hours. Mephenytoin causes sedation, whereas phenytoin does not. The incidence of dose- and time-dependent side effects of mephenytoin is lower than that seen with phenytoin. On the other hand, the incidence of severe and fatal hypersensitivity reactions is far higher than that reported for phenytoin. Therefore, mephenytoin is not the first drug of choice. It is used for the treatment of tonic-clonic, simple partial, and complex partial seizures... 

Tiagabine is used as adjunct therapy in the control refractive partial seizures. When added to other antiepileptic drug regimens, tiagabine significantly decreases seizure frequency (by 50 percent or more) in about 25 percent of patients with refractory complex partial seizures and in roughly 32 percent of patients with simple complex seizures. 

Carbamazepine was probably used at the start of treatment to prevent the automatisms (complex partial seizures) that were reportedly part of the patient s seizure repertoire. Carbamazepine is considered a drug of choice for this seizure type. When it became apparent that such seizures were actually infrequent in this patient, the drug was withdrawn. Carbamazepine has been reported to make absence (or myoclonic) seizures worse. 

Valproic acid has become a major AED against several seizure types. It is highly effective against absence seizures and myoclonic seizures. In addition, valproic acid can be used either alone or in combination with other drugs for the treatment of generalized tonic-clonic epilepsy and for partial seizures with complex symptoms. 

Therapeutic uses Phenytoin is highly effective for all partial seizures (simple and complex), for tonic-clonic seizures, and in the treatment of status epilepticus caused by recurrent tonic-clonic seizures (Figure 15.3). Phenytoin is not effective for absence seizures, which often may worsen if such a patient is treated with this drug. 

Therapeutic uses Carbamazepine is highly effective for all partial seizures (simple and complex) and is often the drug of first choice. In addition the drug is highly effective for tonic-clonic seizures and is used to treat trigeminal neuralgia. It has occasionally been used in manic-depressive patients to ameliorate the symptoms. 

Ethotoin differs from phenytoin in that one phenyl substituent at position 5 has been replaced by hydrogen, and the N-H at position 3 is replaced by an ethyl group (Fig. 20.5). It may be indicated for treatment of tonic-clonic and complex partial (psychomotor) seizures. Because it is considered to be less toxic but also less effective and more sedating than phenytoin, ethotoin usually is reserved for use as an add-on drug (39). Ethotoin does not share phenytoln s profile of antlarrhythmic action. The metabolism of ethotoin, like phenytoin, is saturable and nonlinear. Its administration Is contraindicated in patients with hepatic abnormalities and hematologic disorders. 

Carbamazepine is indicated for use as an anticonvulsant drug. Evidence supports the use of carbamazepine in the control of partial seizures with complex symptomatology (psychomotor, temporal lobe), generalized tonic-clonic seizures (grand mal), and mixed seizure patterns which include the above. Absence seizures (petit mal) do not appear to be controlled by carbamazepine. 

Carbamazepine, an iminostilbene compound, was introduced in the United States in 1974 for the treatment of trigeminal neuralgia. It has become a first-line drug for the treatment of generalized and partial complex seizure disorders, and has found expanded use for pain syndromes, psychiatric illnesses, and drug withdrawal reactions. 

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