SIDE EFFECTS
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
nausea.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.