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 a serious side effect such as:
- fast or pounding heartbeats or fluttering in your chest;
- feeling like you might pass out;
- trouble breathing;
- swelling in your hands, ankles, or feet; or
- penis erection that is painful or lasts 4 hours or longer.
Less serious side effects may include:
- mild dizziness;
- weakness, tired feeling, drowsiness;
- headache; or
This is not a complete list of side effects and others may occur.