Paracetamol

Paracetamol
Paracetamol-skeletal.svg
Paracetamol-from-xtal-3D-balls.png
Clinical data
PronunciationParacetamol: l/
Acetaminophen: n/ (About this soundlisten)
Trade namesTylenol, Panadol, others[2]
SynonymsN-acetyl-para-aminophenol (APAP), acetaminophen (USAN US)
AHFS/Monograph
a681004
License data
Pregnancy
category
  • AU: A
  • US: C (Risk not ruled out) [1]
  • Not tested but seems to be safe
Routes of
administration
By mouth, through the cheek, rectal, intravenous (IV)
ATC code
Legal status
Legal status
Pharmacokinetic data
Bioavailability63–89%[4]:73
Protein binding10–25%[5]
MetabolismPredominantly in the liver[3]
MetabolitesAPAP gluc, APAP sulfate, APAP GSH, APAP cys, NAPQI[6]
Onset of actionPain relief onset by route:
By mouth – 37 minutes[7]
Buccal – 15 minutes[7]
Intravenous – 8 minutes[7]
half-life1–4 hours[3]
ExcretionUrine (85–90%)[3]
Identifiers
103-90-2 ☑Y
1983
5239
DB00316 ☑Y
1906 ☑Y
362O9ITL9D
D00217 ☑Y
CHEBI:46195 ☑Y
ChEMBL112 ☑Y
PDB RCSB PDB)
100.002.870 Edit this at Wikidata
Chemical and physical data
FormulaC8H9NO2
Molar mass151.163 g/mol
3D model (Interactive image
Density1.263 g/cm3
Melting point169 °C (336 °F) [9][10]
Boiling point420 °C (788 °F)
Solubility in water7.21 g/kg (0 °C)[8]

8.21 g/kg (5°C)[8]
9.44 g/kg (10°C)[8]
10.97 g/kg (15°C)[8]
12.78 g/kg (20°C)[8]

~14 mg/mL (20 °C)
  (verify)

Paracetamol, also known as acetaminophen or APAP, is a medicine used to treat pain and fever.[1] It is typically used for mild to moderate pain relief.[1] Evidence for its use to relieve fever in children is mixed.[11][12] It is often sold in combination with other medications, such as in many cold medications.[1] In combination with opioid pain medication, paracetamol is also used for severe pain such as cancer pain and pain after surgery.[13] It is typically used either by mouth or rectally, but is also available intravenously.[1][14] Effects last between 2 and 4 hours.[14]

Paracetamol is generally safe at recommended doses.[15] Serious skin rashes may rarely occur, and too high a dose can result in liver failure.[1] It appears to be safe during pregnancy and when breastfeeding.[1] In those with liver disease, it may still be used, but in lower doses.[16] It is classified as a mild analgesic.[14] It does not have significant anti-inflammatory activity and how it works is not entirely clear.[17]

Paracetamol was first made in 1877.[18] It is the most commonly used medication for pain and fever in both the United States and Europe.[19] It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system.[20] Paracetamol is available as a generic medication with trade names including Tylenol and Panadol, among others.[21] The wholesale price in the developing world is less than US$ 0.01 per dose.[22] In the United States, it costs about US$0.04 per dose.[23]

Medical uses

Fever

Paracetamol is used for reducing fever in people of all ages.[24] The World Health Organization recommends that paracetamol be used to treat fever in children only if their temperature is higher than 38.5 °C (101.3 °F).[25] The efficacy of paracetamol by itself in children with fevers has been questioned[26] and a meta-analysis showed that it is less effective than ibuprofen.[27] Paracetamol does not have significant anti-inflammatory effects.

Pain

Paracetamol is used for the relief of mild to moderate pain.[1] The use of the intravenous form for short-term pain in people in the emergency department is supported by limited evidence.[28]

Osteoarthritis

The American College of Rheumatology recommends paracetamol as one of several treatment options for people with arthritis pain of the hip, hand, or knee that does not improve with exercise and weight loss.[29] A 2015 review, however, found it provided only a small benefit in osteoarthritis.[30]

Paracetamol has relatively little anti-inflammatory activity, unlike other common analgesics such as the nonsteroidal anti-inflammatory drugs (NSAIDs), aspirin, and ibuprofen, but ibuprofen and paracetamol have similar effects in the treatment of headache. Paracetamol can relieve pain in mild arthritis, but has no effect on the underlying inflammation, redness, and swelling of the joint.[31] It has analgesic properties comparable to those of aspirin, while its anti-inflammatory effects are weaker. It is better tolerated than aspirin due to concerns about bleeding with aspirin.

Low back pain

Based on a systematic review, paracetamol is recommended by the American Pain Society as a first-line treatment for low back pain.[32] In contrast, the American College of Physicians found good evidence for NSAIDs but only fair evidence for paracetamol, while other systematic reviews have concluded that evidence for its efficacy is lacking entirely.[30][33][34][35]

Headaches

A joint statement of the German, Austrian, and Swiss headache societies and the German Society of Neurology recommends the use of paracetamol in combination with caffeine as one of several first-line therapies for treatment of tension or migraine headache.[36] In the treatment of acute migraine, it is superior to placebo, with 39% of people experiencing pain relief at 1 hour compared with 20% in the control group.[37]

Postoperative pain

Paracetamol combined with NSAIDs may be more effective for treating postoperative pain than either paracetamol or NSAIDs alone.[38]

Dental use

NSAIDs such as ibuprofen, naproxen, and diclofenac are more effective than paracetamol for controlling dental pain or pain arising from dental procedures; combinations of NSAIDs and paracetamol are more effective than either alone.[39] Paracetamol is particularly useful when NSAIDs are contraindicated due to hypersensitivity or history of gastrointestinal ulceration or bleeding.[40] It can also be used in combination with NSAIDs when these are ineffective in controlling dental pain alone.[41] The Cochrane review of preoperative analgesics for additional pain relief in children and adolescents shows no evidence of benefit in taking paracetamol before dental treatment to help reduce pain after treatment for procedures under local anaesthetic, but the quality of evidence is low.[42]

Other

The efficacy of paracetamol when used in combination with weak opioids (such as codeine) improved for about 50% of people, but with increases in the number experiencing side effects.[43][44] Combination drugs of paracetamol and strong opioids such as morphine improve analgesic effect.[45]

The combination of paracetamol with caffeine is superior to paracetamol alone for the treatment of common pain conditions, including dental pain, post partum pain, and headache.[46]

Patent ductus arteriosus

Paracetamol is used to treat patent ductus arteriosus, a condition that affects newborns when a blood vessel used in developing the lungs fails to close as it normally does, but evidence for the safety and efficacy of paracetamol for this purpose is lacking.[47][48] NSAIDs, particularly indomethacin and ibuprofen, have also been used, but the evidence for them is also not strong.[47] The condition appears to be caused in part by overactive prostaglandin E2 (PGE2), signalling primarily through its EP4 receptor, but possibly also through its EP2 receptor and EP3 receptors.[47]

Other Languages
Afrikaans: Parasetamol
العربية: باراسيتامول
asturianu: Paracetamol
azərbaycanca: Parasetamol
تۆرکجه: استامینوفن
български: Парацетамол
bosanski: Paracetamol
català: Paracetamol
čeština: Paracetamol
Cymraeg: Paracetamol
Deutsch: Paracetamol
ދިވެހިބަސް: ޕެރަސެޓަމޯލް
Ελληνικά: Παρακεταμόλη
español: Paracetamol
Esperanto: Paracetamolo
euskara: Parazetamol
français: Paracétamol
galego: Paracetamol
հայերեն: Պարացետամոլ
hrvatski: Paracetamol
বিষ্ণুপ্রিয়া মণিপুরী: প্যারাসিটামল
Bahasa Indonesia: Parasetamol
íslenska: Parasetamól
italiano: Paracetamolo
עברית: פרצטמול
қазақша: Парацетамол
latviešu: Paracetamols
lietuvių: Paracetamolis
lingála: Paracétamol
magyar: Paracetamol
македонски: Парацетамол
Bahasa Melayu: Parasetamol
Nederlands: Paracetamol
नेपाल भाषा: पारासिटामोल
Nordfriisk: Paracetamol
occitan: Paracetamòl
polski: Paracetamol
português: Paracetamol
română: Paracetamol
русский: Парацетамол
Simple English: Paracetamol
slovenčina: Paracetamol
slovenščina: Paracetamol
کوردی: پانادۆڵ
српски / srpski: Paracetamol
srpskohrvatski / српскохрватски: Paracetamol
Basa Sunda: Parasetamol
svenska: Paracetamol
Türkçe: Parasetamol
українська: Парацетамол
Tiếng Việt: Paracetamol
粵語: 撲熱息痛