Q: Which antiepileptic works good for arrhythmia due to digoxin (cardiac glycosides) acute toxicity?

Answer: Phenytoin

Interestingly, literature in this regard is very old but has been well described.

1. Bashour FA, Edmonson RE, Gupta DN, Prati R. Treatment of digitalis toxicity by diphenylhydantoin (Dilantin). Dis Chest. 1968 Mar;53(3):263–270

2. B H Rumack, R R Wolfe, and H Gilfrich - Phenytoin (diphenylhydantoin) treatment of massive digoxin overdose. - Br Heart J. Apr 1974; 36(4): 405–408.