Possible side effects of acetaminophen include unusual tiredness or weakness, skin rash, hives and itching, according to Mayo Clinic. Additional potential side effects include sore throat unrelated to an existing condition being treated, white spots on the lips or mouth, ulcers or sores. Some people may experience unusual bruising or bleeding.
Additional possible side effects of acetaminophen include pinpoint red spots on the skin, jaundice, increased amounts of urine and severe, sharp pain in the lower back or side, explains Mayo Clinic. Some people get a fever unrelated to an existing condition being treated, and it may be accompanied by the chills. Bloody or black, tarry stools and cloudy or bloody urine are possible side effects of acetaminophen. Side effects of acetaminophen are rare, but if they occur, contact a doctor immediately.
It is possible to overdose on acetaminophen. Signs of an overdose include loss of appetite, increased sweating, nausea, diarrhea and vomiting, states Mayo Clinic. Some people may experience pain or cramps in the stomach. Pain, tenderness or swelling in the stomach or upper abdominal region are signs of an overdose. Some people may experience other unlisted side effects. If any side effects occur, contact a health care professional.