<s>[INST] My father took chemotherapy in 1994. He was well after taking chemotherapy. But before 3/4 years he started to forget some little things like he puts the key to a place after sometime he forgets where does he put the key. He was worried that he was suffering from memory loss due to chemotherapy. We consulted to a local neurologist and he has been taking medicine from last one year(unister 75, elcafort,donetaz 11.5) but after taking the medicines he started to forget major things. In last year december he went to a nearby shop then he forgot the way to home and went to an another place. The day before yesterday the same incident was happened . He was coming from office and he forgot the way to home. My family is really worried after this incident. Does chemotherapy cause memoryloss?? Please give me somesolution [/INST] Hello, Thanks for choosing Chat Doctor for posting your query. I have gone through your question in detail and I can understand what you are going through. Yes, chemotherapy can cause memory loss and the case appears to have progressed to the level of dementia. He will need Chat Doctor.  For such severe cases one should consider Semantic 5 mg and then gradually increase it to 20 mg. It's an FDA approved  </s>