Your best bet is to actually call the pharmacist. While doctors SHOULD know the answer to this question, pharmacists are better educated about this. The one thing I can tell you about any weight loss drug is that even though they may be safe to take together, anytime I've taken them (or even green tea), my heart rate goes through the roof and I get jittery. So, even if the drugs are safe together, if you notice increased anxiety, this could be why.
www.drugs.com you can put in meds and it can tell you potential side effects etc. But honestly you can always call your doc anytime and they can tell you too. I used to take Phentermine and Zoloft together and it was fine but every med is different.
Think that you should go back to your doctor and discuss this with your doctor.