Get emergency medical help if you have any of these signs of an allergic reaction to Excedrin: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
In rare cases, acetaminophen may cause a severe skin reaction that can be fatal. This could occur even if you have taken acetaminophen in the past and had no reaction. Stop taking Excedrin and call your doctor right away if you have skin redness or a rash that spreads and causes blistering and peeling. If you have this type of reaction, you should never again take any medicine that contains acetaminophen.
Stop using Excedrin and call your doctor at once if you have:
severe anxiety, agitation, confusion, panic;
easy bruising or bleeding;
a light-headed feeling, like you might pass out;
if you feel very thirsty or hot, are unable to urinate, and have heavy sweating or hot and dry skin;
symptoms of stomach bleeding--bloody or tarry stools, coughing up blood or vomit that looks like coffee grounds;
high potassium--slow heart rate, weak pulse, muscle weakness, tingly feeling; or
liver problems--nausea, upper stomach pain, itching, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).
Common Excedrin side effects may include:
upset stomach, heartburn;
depressed mood, feeling anxious or restless; 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.
 Excedrin side effects (more detail)
