Hello!
At 68 kgs and 168cm your BMI is 24.1 and normal
Sibutramine(reductil) is for treatment of obesity and you are not obese.
There are lots of side effects with reductil and should only be taken under prescription and it acts on neurotransmitters and cuts down your hunger.
For you to lose further 5 kgs you have to go for cardio activities like running, jogging, skipping, swimming, cycling, etc for a period of 30 minutes regularly.
Take care!
you dont need to lose 10kg
anyway, you need to watch your food quality and calories intake
if you do excercise on regular basis and eleminate all excess fat from your food then you will definitely lose weight
take fruits and youghurt as snack and lots of vegetables and limit your carbs and fat. if you feel hungry, try to have salads or apples or snack with some broccoli and asparagus
avoid processed foods as well.