Get emergency medical help if you have signs of an allergic reaction to tadalafil: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Stop and get medical help at once if you have nausea, chest pain, or dizziness during sex. You could be having a life-threatening side effect.
Stop using tadalafil and call your doctor at once if you have:
a light-headed feeling, like you might pass out;
an erection is painful or lasts longer than 4 hours (prolonged erection can damage the penis);
vision changes or sudden vision loss;
ringing in your ears or sudden hearing loss; or
heart attack symptoms - chest pain or pressure, pain spreading to your jaw or shoulder, nausea, sweating.
Common tadalafil side effects may include:
headache;
flushing (warmth, redness, or tingly feeling);
nausea, upset stomach;
stuffy nose; or
muscle pain, back pain, pain in your arms, legs, or back.
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.
 Tadalafil side effects (more detail)
