need moore every time lithium

Hello , i hope i can get help on this cuestion.

when i did star taking lithium 150mg was very confution . no consentrtion at work very confuse

but after a 3 month star workin perfet . an only last me 4 good month of medicine an now

from 150 to 450 . my DR. tell me the I have to check my bloab i jas wonder why????

Alvaro Soto