My 12 lbs cat has constipation and he's on Lactulose by my vet, 2ml every 12 hours. It works in 24 hrs, faster than what I expected. (it's said it takes a couple days to work) I asked if I should reduced the dosage from now (like 1.5ml each time?), the vet said I should keep the same amount for 14 days. Somehow I think 2ml seems a lot to me and I hope it won't become additive?