My sister has bipolar disorder and recently...

lithium for injection ?
the form of lithium for injection is available for human consumbtion only via iv injection rather than that its used in animals as im injection
where i can find lithium injection ?
sorry its unavailable unless in the large psychiatry hospitals and not for people to buy 
what is the alternatives of lithium caps for the treatment of bipolar disorder ?

• we suggest using a liquid form of the drug that is available in form of lithuim citrate and its available almost in every large pharmacy 
• another method is to take lithium pills ( not capsules ) and dissolve it in water then drink it 

is gastric sleev makes you not able to take capsuls ?
yes you should not eat capsules or pills untill 2 weeks post operation but as a simple solution the doctors usually prescribe the drug and recommend to dissove it in water then drink it till the 2 weeks period pass by then you shoud be able to resume taking the pills that you have used to take prior surgery