Combined application of propranolol and local anesthetics: enhanced anticonvulsant action.

The influence of the local anesthetics procaine and lidocaine on the anticonvulsant action of propranolol was investigated using the maximal electroshock seizure test in mice. Combined application markedly reduced ED50 values either of the local anesthetics or of propranolol. Selected anticonvulsants and antiarrhythmics were tested by comparison. Similar results could be obtained with phenytoin and isatin when administered together with propranolol, whereas procainamide and quinidine failed to exert synergism in a higher degree or in general. Na-Ca-exchange on the membrane level may be a link for the interpretation of the reported findings, since most of the drugs tested are involved in these processes.