Tylenol (acetaminophen) is an analgesic (pain reliever) and fever reducer. Tylenol 500 mg is considered “extra strength.”
Tylenol 500 mg is used to temporarily reduce fever and for temporary relief of minor aches and pains due to:
- Headache
- Backache
- Minor arthritis pain
- Muscle aches
- The common cold
- Toothaches
- Premenstrual and menstrual cramping
The dose of Tylenol 500 mg is 1 to 2 tablets every four to six hours. The safest maximum daily dose of Tylenol 500 mg for adults is 6 tablets (3000 mg). Never take more than 8 pills (4000 mg) in 24 hours.
Taking the maximum daily dose for extended periods can cause serious damage to the liver. If you are experiencing chronic pain and feel that you need more than 3000 mg of Tylenol in one day, talk to your doctor.
What Are Side Effects of Tylenol 500 mg?
While Extra Strength Tylenol is a commonly used over-the-counter pain reliever, it has the potential risk for side effects as with any other medication.
Side effects of Tylenol 500 mg (acetaminophen) include:
- Nausea
- Loss of appetite
- Stomach pain
- Headache
- Rash (may itch)
- Clay-colored stools
- Dark urine
- Yellowing of skin or eyes (jaundice)
What Are Serious Side Effects of Tylenol 500 mg?
Serious side effects of Extra Strength Tylenol (500 mg) include:
- Skin swelling (angioedema)
- Hives
- Low levels of red blood cells, white blood cells, and/or platelets
- Disorientation
- Shortness of breath
- Cough
- Liver toxicity/liver failure
- Severe allergic reaction (anaphylaxis)
- Stevens-Johnson syndrome
- Toxic epidermal necrolysis
- Gastrointestinal hemorrhage
- Laryngeal edema
- Hyperammonemia
- Kidney toxicity
- Low white blood cell count (leukopenia, neutropenia)
- Low platelet count (thrombocytopenia)
- Low red and white blood cell count and low platelet count (pancytopenia)
- Agranulocytosis
Can Tylenol 500 mg Be Used During Pregnancy or While Breastfeeding?
- Tell your doctor if you are pregnant or plan to become pregnant before using Tylenol 500 mg (acetaminophen). Tylenol 500 mg may be acceptable for short-term use during pregnancy.
- Tylenol passes into breast milk but is considered compatible with breastfeeding. Consult your doctor before breastfeeding.
From 
https://reference.medscape.com/drug/tylenol-acetaminophen-343346
https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=1622f694-4d63-4c56-8737-fae31f0ecfb7
https://www.tylenol.com/products/tylenol-extra-strength-caplets
https://www.rxlist.com/tylenol-side-effects-drug-center.htm
https://www.health.harvard.edu/pain/acetaminophen-safety-be-cautious-but-not-afraid