ETHOTOIN

Absorption

Fairly rapidly absorbed, however, the extent of oral absorption is not known.

Toxicity

Symptoms of overdose include drowsiness, loss of or impaired muscle coordination, nausea, visual disturbance, and, at very high doses, coma.

Originator

Peganone,Abbott,US,1957

The Uses of ETHOTOIN

Ethotoin is less active and less toxic than phenytoin. It is used for the same indications as is phenytoin, i.e. for control of major and complex epileptic attacks.

The Uses of ETHOTOIN

Ethotoin is a hydantoin based anticonvulsant drug used in the treatment of epilepsy.

Background

Ethotoin is a hydantoin derivative and anticonvulsant. Ethotoin exerts an antiepileptic effect without causing general central nervous system depression. The mechanism of action is probably very similar to that of phenytoin. The latter drug appears to stabilize rather than to raise the normal seizure threshold, and to prevent the spread of seizure activity rather than to abolish the primary focus of seizure discharges. Ethotoin is no longer commonly used.

Indications

For the control of tonic-clonic (grand mal) and complex partial (psychomotor) seizures.

Definition

ChEBI: An imidazolidine-2,4-dione that is hydantoin substituted by ethyl and phenyl at positions 3 and 5, respectively. An antiepileptic, it is less toxic than phenytoin but also less effective.

Manufacturing Process

Benzaldehyde cyanohydrin is reacted with urea to displace the hydroxyl group of the cyanohydrin. That intermediate is treated with HCl to convert the urea nitrogen to a nitrile. The resultant imine is hydrolyzed to the phenylhydantoin. Alkylation with ethyl iodide gives ethotoin, as described by A. Pinner in Chem. Ber. 21, 2325 (1888).

brand name

Peganone (Ovation.

Therapeutic Function

Anticonvulsant

Pharmacokinetics

Ethotoin is a hydantoin derivative and anticonvulsant. Ethotoin exerts an antiepileptic effect without causing general central nervous system depression. The mechanism of action is probably very similar to that of phenytoin. The latter drug appears to stabilize rather than to raise the normal seizure threshold, and to prevent the spread of seizure activity rather than to abolish the primary focus of seizure discharges.

Synthesis

Ethotoin, 3-ethyl-5-phenylimidazolidine-2,4-dione (9.1.5), is synthesized in basically the same manner as described above, which in this case involves the reaction of benzaldehyde oxynitrile (9.1.2), with urea or ammonium hydrocarbonate, which forms the intermediate urea derivative (9.1.3) which on acidic conditions (9.1.3) cyclizes to 5-phenylhydantoin (9.1.4). Alkylation of this product using ethyliodide leads to the formation of ethotoin (9.1.5) [3,4].

Metabolism

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. 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. Ethotoin does not share phenytoin's profile of antiarrhythmic action. The metabolism of ethotoin, like phenytoin, is saturable and nonlinear. Its administration is contraindicated in patients with hepatic abnormalities and hematologic disorders.

Metabolism

Hepatic. The drug exhibits saturable metabolism with respect to the formation of N-deethyl and p-hydroxyl-ethotoin, the major metabolites.

Purification Methods

It is an anticonvulsant and is used in epilepsy. [Dudley et al. J Heterocycl Chem 10 173 1973, Pinner Chem Ber 21 2320 1888, Beilstein 25 III/IV 963, 27 II 860.]