Goodafternoon sir, My question is -one of my my patients having aged 80 years.She is suffering from Sevre Backpain and Bodyache,they r nt interest to do further Rx for it only want relief.Can i prescribe Methycobal injection 500 mg Alternate day or once in a week for 4 inj. for leg pain etc.after test dose oor directly. can he take 500 mg at this age and i doubt whether i precibe for 500 mg instead 500 mcg. What will happen if test dose is not given? please clarify sir.