Paracetamol

Paracetamol
Clinical data
PronunciationParacetamol: /ˌpærəˈsiːtəmɒl/
Acetaminophen: /əˌsiːtəˈmɪnəfɪn/ ⓘ
Trade namesTylenol, Panadol, others[1]
Other namesN-acetyl-para-aminophenol (APAP), acetaminophen (USAN US)
AHFS/Drugs.comMonograph
MedlinePlusa681004
License data
Pregnancy
category
Routes of
administration		By mouth, rectal, intravenous (IV)
Drug class
ATC code
Legal status
Legal status
Pharmacokinetic data
Bioavailability63–89%[5]: 73 
Protein bindingnegligible to 10–25% in overdose[6]
MetabolismPredominantly in the liver[9]
MetabolitesAPAP gluc, APAP sulfate, APAP GSH, APAP cys, AM404, NAPQI[7]
Onset of actionOral: 37 minutes[8]
Intravenous: 8 minutes[8]
Elimination half-life1.9–2.5 hours[6]
ExcretionKidney[6]
Identifiers
  • N-(4-hydroxyphenyl)acetamide
CAS Number
PubChem CID
PubChem SID
IUPHAR/BPS
DrugBank
ChemSpider
UNII
KEGG
ChEBI
ChEMBL
PDB ligand
CompTox Dashboard (EPA)
ECHA InfoCard100.002.870 Edit this at Wikidata
Chemical and physical data
FormulaC8H9NO2
Molar mass151.165 g·mol−1
3D model (JSmol)
Density1.293 g/cm3
Melting point169 °C (336 °F) [10][11]
Solubility in water
  • 7.21 g/kg (0 °C)[12]
  • 8.21 g/kg (5 °C)[12]
  • 9.44 g/kg (10 °C)[12]
  • 10.97 g/kg (15 °C)[12]
  • 12.78 g/kg (20 °C)[12]
  • ~14 mg/ml (20 °C)
  • CC(=O)Nc1ccc(O)cc1
  • InChI=1S/C8H9NO2/c1-6(10)9-7-2-4-8(11)5-3-7/h2-5,11H,1H3,(H,9,10) checkY
  • Key:RZVAJINKPMORJF-UHFFFAOYSA-N checkY
  (verify)

Paracetamol[a], or acetaminophen[b], is a non-opioid analgesic and antipyretic agent used to treat fever and mild to moderate pain.[13][14][15] It is a widely used over-the-counter medication. Common brand names include Tylenol and Panadol.

Paracetamol relieves pain in both acute mild migraine and episodic tension headache.[16][17] At a standard dose, paracetamol slightly reduces fever;[14][18][19] it is inferior to ibuprofen in that respect,[20] and the benefits of its use for fever are unclear, particularly in the context of fever of viral origins.[14][21][22] The aspirin/paracetamol/caffeine combination also helps with both conditions where the pain is mild and is recommended as a first-line treatment for them.[23][24] Paracetamol is effective for post-surgical pain, but it is inferior to ibuprofen.[25] The paracetamol/ibuprofen combination provides further increase in potency and is superior to either drug alone.[25][26] The pain relief paracetamol provides in osteoarthritis is small and clinically insignificant.[15][27][28] The evidence in its favor for the use in low back pain, cancer pain, and neuropathic pain is insufficient.[15][27][29][30][31][32]

In the short term, paracetamol is safe and effective when used as directed.[33] Short term adverse effects are uncommon and similar to ibuprofen,[34] but paracetamol is typically safer than nonsteroidal anti-inflammatory drugs (NSAIDs) for long-term use.[35] Paracetamol is also often used in patients who cannot tolerate NSAIDs like ibuprofen.[36][37] Chronic consumption of paracetamol may result in a drop in hemoglobin level, indicating possible gastrointestinal bleeding,[38] and abnormal liver function tests. The recommended maximum daily dose for an adult is three to four grams.[27][39] Higher doses may lead to toxicity, including liver failure.[40] Paracetamol poisoning is the foremost cause of acute liver failure in the Western world, and accounts for most drug overdoses in the United States, the United Kingdom, Australia, and New Zealand.[41][42][43]

Paracetamol was first made in 1878 by Harmon Northrop Morse or possibly in 1852 by Charles Frédéric Gerhardt.[44][45][46] It is the most commonly used medication for pain and fever in both the United States and Europe.[47] It is on the World Health Organization's List of Essential Medicines.[48] Paracetamol is available as a generic medication, with brand names including Tylenol and Panadol among others.[49] In 2022, it was the 114th most commonly prescribed medication in the United States, with more than 5 million prescriptions.[50][51]

  1. ^ International Drug Names
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