Get emergency medical help if you have any of these signs of an allergic reaction to Bystolic: hives; difficult breathing; swelling of your face, lips, tongue, or throat. Call your doctor at once if you have a serious side effect such as:
feeling short of breath, even with mild exertion;
swelling of your ankles or feet;
slow or uneven heartbeats; or
numbness or cold feeling in your hands and feet.
Less serious Bystolic side effects may include:
headache;
tired feeling;
nausea, stomach pain;
diarrhea; or
sleep problems (insomnia).
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
 Bystolic side effects (more detail)
