Influence of isradipine, niguldipine and dantrolene on the anticonvulsive action of conventional antiepileptics in mice.
We report the effects of two new dihydropyridine derivatives, isradipine (4-(4'-benzofurazanyl)-1,4-dihydro-2,6-dimethyl-3,5-pyridinedic arboxylic acid methylisopropylester) and niguldipine (1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-3,5-pyridinecarboxylic acid 3-(4,4-diphenyl-1-piperidinyl)-propyl methyl ester hydrochloride), and of dantrolene (1-[(5-[p-nitrophenyl]furfurylidene)-amino]hydantoin sodium, an inhibitor of Ca2+ release from intracellular stores) on the protective efficacy of antiepileptic drugs against maximal electroshock-induced seizures. It was shown that dantrolene (5-20 mg/kg), isradipine (5-10 mg/kg) and niguldipine (up to 2.5 mg/kg) did not influence the electroconvulsive threshold in mice, although a higher dose of niguldipine (5 mg/kg) significantly elevated it. Dantrolene (10-20 mg/kg) and isradipine (1 mg/kg) did not affect the anticonvulsive activity of conventional antiepileptic drugs. In contrast, niguldipine (2.5-5 mg/kg) impaired the protective action of carbamazepine and phenobarbital. No effect of niguldipine (2.5-5 mg/kg) was observed upon the anticonvulsive efficacy of diphenylhydantoin and valproate. BAY k-8644 (methyl-1,4-dihydro-2,6-dimethyl-5-nitro-4- [(2-trifluoromethyl)-phenyl]-pyridine-5-carboxylate, an L-type Ca2+ channel agonist) did not reverse the action of niguldipine alone or the niguldipine-induced impairment of the anticonvulsive action of carbamazepine and phenobarbital. Niguldipine did not influence the free plasma levels of carbamazepine and phenobarbital, so a pharmacokinetic interaction is not probable. The results suggest that in contrast to the anticonvulsive activity of niguldipine against electroconvulsions, this Ca2+ channel inhibitor significantly weakened the protective action of both carbamazepine and phenobarbital. These effects do not seem to result from the blockade of voltage-dependent Ca2+ channels. Isradipine and dantrolene did not have a modulatory action on the threshold for electroconvulsions or on the anticonvulsive activity of antiepileptic drugs. It may be concluded that the use of niguldipine, isradipine, and dantrolene in epileptic patients seems questionable.
Borowicz
K K
KK
Department of Pharmacology and Toxicology, Lublin Medical University School, Poland.
Gasior
M
M
Kleinrok
Z
Z
Czuczwar
S J
SJ
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D000927:Anticonvulsants / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D002120:Calcium Channel Agonists / Q000008:administration & dosage / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000008:administration & dosage / Q000633:toxicity*; D002220:Carbamazepine / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology / Q000627:therapeutic use; D003620:Dantrolene / Q000008:administration & dosage / Q000633:toxicity*; D004095:Dihydropyridines / Q000008:administration & dosage / Q000633:toxicity*; D004195:Disease Models, Animal; D004347:Drug Interactions; D004597:Electroshock / Q000009:adverse effects; D004827:Epilepsy / Q000188:drug therapy; D005260:Female; D017275:Isradipine / Q000008:administration & dosage / Q000633:toxicity*; D007928:Lethal Dose 50; D051379:Mice; D009043:Motor Activity / Q000187:drug effects; D010634:Phenobarbital / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology / Q000627:therapeutic use; D010672:Phenytoin / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D011897:Random Allocation; D012640:Seizures / Q000188:drug therapy / Q000209:etiology; D014635:Valproic Acid / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use
D000927:Anticonvulsants; D002120:Calcium Channel Agonists; D002121:Calcium Channel Blockers; D004095:Dihydropyridines; D002220:Carbamazepine; D014635:Valproic Acid; D010672:Phenytoin; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D003620:Dantrolene; D017275:Isradipine; D010634:Phenobarbital; C054074:niguldipine