Influence of carbenoxolone on the anticonvulsant efficacy of conventional antiepileptic drugs against audiogenic seizures in DBA/2 mice

• Published in: European journal of pharmacology Vol. 484; no. 1; pp. 49 - 56
• Main Authors: Gareri, Pietro, Condorelli, Daniele, Belluardo, Natale, Gratteri, Santo, Ferreri, Guido, Donato Di Paola, Eugenio, De Sarro, Angela, De Sarro, Giovambattista
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 19.01.2004; Elsevier
• Subjects: Acoustic Stimulation - adverse effects; Acoustic Stimulation - methods; Animals; Anticonvulsant potency; Anticonvulsants - pharmacokinetics; Anticonvulsants - therapeutic use; Antiepileptic drug; Audiogenic seizure; Biological and medical sciences; Carbamazepine; Carbenoxolone; Carbenoxolone - pharmacokinetics; Carbenoxolone - therapeutic use; DBA/2; Drug Synergism; Epilepsy; Epilepsy, Reflex - blood; Epilepsy, Reflex - drug therapy; Felbamate; Gap junction; Medical sciences; Mice; Mice, Inbred DBA; Motor Activity - drug effects; Motor Activity - physiology; mouse; Pharmacology. Drug treatments; Phenytoin; Valproate; Antiepileptic drug; Carbenoxolone; Felbamate; Epilepsy; Anticonvulsant potency; DBA/2; Gap junction; Carbamazepine; Phenytoin; Valproate; Audiogenic seizure; Drug; Nervous system diseases; Rodentia; Antiinflammatory agent; Anticonvulsant; Cerebral disorder; Audiogenic epilepsy; Vertebrata; Mammalia; Mouse; Animal; Central nervous system disease
• ISSN: 0014-2999; 1879-0712
• DOI: 10.1016/j.ejphar.2003.10.047

Carbenoxolone, the succinyl ester of glycyrrhetinic acid, is an inhibitor of 11β-hydroxy steroid dehydrogenase and gap junctional intercellular communication. It is currently used in clinical treatment of ulcer diseases. Systemic administration of carbenoxolone (1–40 mg/kg, intraperitoneally (i.p.)) was able to produce a dose-dependent decrease in DBA/2 audiogenic seizure severity score. Glycyrrhizin, an analogue of carbenoxolone inactive at the gap-junction level, was unable to affect audiogenic seizures at doses up to 30 mg/kg. In combination with conventional antiepileptic drugs, carbenoxolone, 0.5 mg/kg, i.p., which per se did not significantly affect the occurrence of audiogenic seizures in DBA/2 mice, potentiated the anticonvulsant activity of carbamazepine, diazepam, felbamate, gabapentin, lamotrigine, phenytoin, phenobarbital and valproate against sound-induced seizures in DBA/2 mice. This effect was not observed after the combination of glycyrrhizin (10 mg/kg, i.p.) with some conventional antiepileptic drugs. The degree of potentiation induced by carbenoxolone was greater for diazepam, felbamate, gabapentin, phenobarbital and valproate, less for lamotrigine, phenytoin and carbamazepine. This increase was associated with a comparable impairment in motor activity; however, the therapeutic index of combined treatment of antiepileptic drugs with carbenoxolone was more favourable than the combination with glycyrrhizin or saline. Since carbenoxolone did not significantly influence the total and free plasma levels of diazepam, felbamate, gabapentin, lamotrigine, phenytoin, phenobarbital, valproate and carbamazepine, pharmacokinetic interactions are not likely. However, the possibility that carbenoxolone can modify the brain clearance of the anticonvulsant drugs studied may not be excluded. In addition, carbenoxolone did not significantly affect the hypothermic effects of the anticonvulsants tested. In conclusion, carbenoxolone showed an additive anticonvulsant effect when administered in combination with some classical anticonvulsants, most notably diazepam, felbamate, gabapentin, phenobarbital, and valproate, implicating a possible therapeutic relevance of such drug combinations.