Is cystone tablet good? Can be taken?

I have been having history of kidney stones since 2008. I have undergone bilateral RIRS twice.once in 2010 and last year on May 2016.we have done 24 hour urine analysis and everything is fine..doctor has not prescribed any medicine post surgery last May 2016.I also did a stone analysis this time and found that it was majorly calcium oxalate stone with traces of struvite stone..I want to prevent reoccurence of stone in future and want to take some preventive medication for the same..I have been drinking 2 litres per day and i know in shld drink more.. My question to a urologist is I have heard about a medicine from himalaya drug company by name Cystone.one of the doctor asked me to take 2 in morning and 2 in night daily as this will prevent stone occurence..I want to know whether this medicine is safe and can be taken daily to prevent reoccurence of stone.. Also pls let me know if any other medicine can be taken? Looking forward for an advice from a specialist urologist..Thanks...