Some common side effects of this medication include:

Lightheadedness
Headaches
Mild nausea (should be mild and pass quickly. If it doesn’t, contact a medical professional immediately.)
Mild diarrhea (Like nausea, anything that is more than mild or lasts longer than a few days, you should contact a medical professional.)
Signs of allergic reactions include hives, itching, swelling of your tongue/throat/mouth, or shortness of breath.

If you think you are experiencing an allergic reaction when taking this medication, you should seek medical help immediately.

There are some other side effects that you may experience, which could be more related to losing weight rather than the medication. These symptoms include:

Jitteriness
Irritability
Extreme fatigue
Hunger pangs
Upset gastrointestinal tract