How Long Does Tylenol Stay in Your System?

Tylenol's Makeup and Use

To understand how long Tylenol stays in your system, you must know what the drug is and how it is used and metabolized by your body. Tylenol is the brand name for acetaminophen, an over-the-counter analgesic (or pain reliever) and antipyretic (or fever reducer). The drug is used to treat headaches, colds and fevers, as well as other body aches and pains. Many cold and flu remedies found at drugstores contain acetaminophen. It is often combined with other drugs, such as antihistamines or cough suppressants to create multi-symptom relieving formulas.

How Long Acetaminophen Lasts

Acetaminophen is usually taken orally and is quickly absorbed from the gastrointestinal tract into the bloodstream, namely the plasma. Its effects are generally felt within 30 to 45 minutes 1. It is metabolized by the liver, enters the bloodstream and is later excreted via urine. The term "half-life" is used to determine how long it takes a medication or drug to be eliminated from blood plasma by one half of its strength. Once the drug is no longer in blood plasma, it loses its detectability. Therefore, after its half-life ends, the drug is no longer in the bloodstream.

The half-life of acetaminophen is 1 to 2 ½ hours in most people, meaning that it is detectable up to that point, but not much longer afterward, as the drug is exiting the blood to be excreted by urine. Within six to eight hours, only tiny, generally undetectable traces of the drug are left.

Therefore, Tylenol stays in your body no longer than six to eight hours.