Progabide Phenytoin

Figure 16.7 The structure of some established antiepileptic drugs (AEDs) and some newer ones. Note that while the structures of phenytoin and ethosuximide are similar and also close to that of phenobarbitone, they are effective in different forms of epilepsy. Vigabatrin, progabide and gabapentin are clearly related to GABA. Muscimol is a GABAa agonist but is not an effective antiepileptic drug...

Progabide may raise phenytoin levels and alter the serum levels of carbamazepine, clonazepam, phenobarbitaL The effect of these antiepileptics on progabide levels appears to be only moderate or small. 

Marked increases in serum phenytoin levels have been seen in a few patients also given progabide, " while smaller changes have been described in some studies, - and negligible ehanges in others. ... 

Information about antiepilepties other than phenytoin is limited, but progabide is reported to minimally reduee, - minimally increase or not to change carbamazepine - " serum levels. An increase of up to 24% in the levels of earbamazepine-10,11-epoxide (the active metabolite of carbamazepine) has also been reported. - Vaiproate, - " and clonazepam" serum levels were not significantly affected by progabide. Progabide appears to eause a small inerease in serum phenobarbital levels, which is of little elinieal importanee. - " ... 

Some small to moderate ehanges in the serum levels of carbamazepine, phenobarbital, valproate and elonazepam ean apparently occur in the presence of progabide, but only the interaetion with phenytoin appears to be... 

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