Before taking phentermine, tell your doctor if you are using any of the following drugs:
medicines to treat high blood pressure;
insulin or diabetes medication you take by mouth;
guanadrel (Hylorel), guanethidine (Ismelin);
antidepressants such as citalopram (Celexa), escitalopram (Lexapro), fluoxetine (Prozac, Sarafem), fluvoxamine (Luvox), paroxetine (Paxil), or sertraline (Zoloft); or
antidepressants such as amitriptyline (Elavil, Etrafon), amoxapine (Ascendin), clomipramine (Anafranil), desipramine (Norpramin), doxepin (Sinequan), imipramine (Janimine, Tofranil), nortriptyline (Pamelor), protriptyline (Vivactil), or trimipramine (Surmontil).
If you are using any of these drugs, you may not be able to use phentermine, or you may need dosage adjustments or special tests during treatment.
There may be other drugs not listed that can affect phentermine. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.