How Long Does It Take for Tylenol (Acetaminophen) to Start Working?

Family Medicine, Roots Community Health Center, Hippo Education, Kameda Medical Center

Supervised by Kenji Taylor, MD, MSc

Tylenol, or acetaminophen, is a commonly used over-the-counter medication for pain relief and fever reduction. It takes about 30-60 minutes to start working after taking it.

Explanation

Onset of Action

Timeframe: Acetaminophen typically starts to work within 30 minutes to 1 hour after ingestion. The peak effect is usually observed around 1 to 2 hours after taking the medication.
Factors Influencing Onset:

Pharmacokinetics

Absorption: Acetaminophen is rapidly absorbed from the gastrointestinal tract, which contributes to its relatively quick onset of action.
Distribution: Once absorbed, it is distributed throughout the body, including the central nervous system, where it exerts its analgesic effects.

(References)

Shinoda S, Aoyama T, Aoyama Y, Tomioka S, Matsumoto Y, Ohe Y. Pharmacokinetics/pharmacodynamics of acetaminophen analgesia in Japanese patients with chronic pain. Biol Pharm Bull. 2007 Jan;30(1):157-61. doi: 10.1248/bpb.30.157. PMID: 17202677.
Hakim M, Anderson BJ, Walia H, Tumin D, Michalsky MP, Syed A, Tobias JD. Acetaminophen pharmacokinetics in severely obese adolescents and young adults. Paediatr Anaesth. 2019 Jan;29(1):20-26. doi: 10.1111/pan.13525. Epub 2018 Nov 28. PMID: 30484909.
Forrest JA, Clements JA, Prescott LF. Clinical pharmacokinetics of paracetamol. Clin Pharmacokinet. 1982 Mar-Apr;7(2):93-107. doi: 10.2165/00003088-198207020-00001. PMID: 7039926.

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