Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Call your doctor at once if you have any of these serious side effects:

blurred vision or temporary blindness;

fever;
slow heart rate, trouble breathing;
anxiety, agitation, shivering;
feeling light-headed, fainting; or
urinating less than usual or not at all.

Other less serious side effects are more likely to occur, such as:

diarrhea or constipation;
weakness or tired feeling;
headache;
dizziness or drowsiness;

Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.