The administration of Biperiden in combination with other anticholinergic psychotropic drugs, antihistamines, antiparkinsonian drugs and antispasmodics can potentiate the CNS and peripheral side effects. The concomitant intake of quinidine may potentiate the anticholinergic effect (especially AV conduction). The concurrent administration of levodopa and Biperiden may potentiate dyskinesia. Generalised choriec movements have been reported in Parkinson's disease following concurrent administration of carbidopa/levodopa and Biperiden. Tardive dyskinesia induced by presence of existing tardive are occasionally so serious as to mandate continued anticholinergic therapy. The effect of metoclopramide and compounds with similar activity on the gastrointestinal tract is attenuated by anticholinergics such as Biperiden. As with all other drugs acting on the central nervous system, the consumption of alcohol should be avoided under Biperiden therapy.