Toxicity of quinacrine can be reduced by co-administration of P-glycoprotein inhibitor in sporadic Creutzfeldt-Jakob disease.

1. Recent publication has suggested that quinacrine may be a candidate for treatment of Creutzfeldt-Jakob disease (CJD). But serious toxicity of quinacrine to liver and hematological system has been reported. 2. We disclosed the permeability of quinacrine can be enhanced by presence of p-glycoprotein inhibitor at blood-brain barrier in vitro. Therefore, we tried the protocol of combination of quinacrine and p-glycoprotein inhibitor, verapamil for patients with CJD. 3. When compared clinical effects by quinacrine and the combination therapy, improvement of clinical findings was observed at the same level without any adverse effects. Low-dose quinacrine with verapamil can be used as safe treatment of CJD.