Acetaminophen is the most commonly taken analgesic (pain reliever) worldwide and is recommended as first-line therapy in pain management by the WHO. It is also used for its antipyretic effects, helping to reduce fever. The drug was initially approved by the F.D.A in 1951.

Acetaminophen (paracetamol; N-acetyl-p-aminophenol; TYLENOL, others) is the active metabolite of phenacetin.

Formula: C8H9NO2

It is available as an over-the-counter pain relief medication and is used as a common household analgesic. Acetaminophen is an effective alternative to aspirin as an analgesic-anti-pyretic, however, its anti-inflammatory effects are much weaker. It is well tolerated and has a low incidence of gastrointestinal side-effects. However, an acute over-dose causes severe hepatic damage.

 

 

Mechanism of action of Acetaminophen:

 

The exact mechanism of action of acetaminophen is not yet. But It beliefs that, It blocks the production of cyclooxygenase-3 in the brain that reduces the production of prostaglandins (PGE) in the central nervous system.

Prostaglandins are chemicals that cause inflammation and swelling. Acetaminophen reduces pain by elevating the pain regulating center of the brain. It is believed that Acetaminophen relieves pain by increasing the pain threshold level.

 

 

Adult dosage and strength:

 

The adult dose of acetaminophen is 325-650 mg every 4 hours or 500 mg every 8 hours. The maximum daily dose is 4 grams per day.

The oral dose for a child:

If less than years of age, the dosing is 10-15 mg/kg every 6-8 hours not to exceed 2.6 g/day.

 

 

Dosage Forms and Strength of Acetaminophen

 

Tablet

• 325mg

• 500mg

Capsule

• 325mg

• 500mg

Tablet, oral-disintegrating

• 80mg

• 160mg

Tablet chewable

• 80mg

Solution or suspension, oral

• 160mg/5mL

Liquid oral

• 160mg/5mL

• 500mg/5mL

Syrup oral

• 160mg/5mL

 

 

 

Combinations with other medication

 

The drug is also available in a fixed-dose combination containing narcotics and non-narcotic analgesics, barbiturates, caffeine, anti-histamines, anti-tussive (cough suppressants), and decongestant treatments.

Acetaminophen is also used in conjugation with opiates to manage moderate to severe pain.

 

 

Therapeutic uses of Acetaminophen:

 

Acetaminophen is used to relieve pain, fever as well as aches associated with many conditions. If the pain is not due to inflammation, acetaminophen is as effective as aspirin.

Acetaminophen is suitable for analgesic or antipyretic uses, it is the 1^st–line analgesic in osteoarthritis and particularly valuable for patients whom aspirin is contraindicated.

Acetaminophen is an analgesic mostly used to relieve minor aches and pains due to headache, muscle aches, backache, and mild pain of arthritis, the common cold, toothache, and premenstrual and menstrual cramps. Acetaminophen is also used to temporarily reduce fever.

 

 

Is Acetaminophen safe to take in pregnancy or in breastfeeding mothers?

 

 Acetaminophen is excreted in breast milk in small quantities. However, acetaminophen use by the nursing mother appears to be safe.

Use of normal doses during pregnancy not associated with an increased risk of miscarriage or teratogenic effects; however, an increase in fetal death or spontaneous abortion may be seen with maternal overdose if treatment delayed.

 

 

Side effects of Acetaminophen

 

Though acetaminophen is well-tolerated, side effects of acetaminophen are not common. Some side effects may be nausea, vomiting, and rash (hypersensitivity reactions).

Acetaminophen toxicity include;

 

Hepatotoxicity:

For the average healthy adult, the generally recommended maximum daily dose is no more than 4,000 milligrams (mg) from all sources. Adults should not take more than 4000 milligrams (4 grams) of acetaminophen a day

In adults, hepatotoxicity may occur often after ingestion of a single dose of 7.5-10 grams of acetaminophen.

 

 

 

References

1. Acetaminophen. (n.d.). Retrieved from WebMD: https://www.webmd.com/drugs/2/drug-362/acetaminophen-oral/details
2. acetaminophen (OTC). (n.d.). Retrieved from Medscape: https://reference.medscape.com/drug/tylenol-acetaminophen-343346#6
3. Acetaminophen safety: Be cautious but not afraid. (n.d.). Retrieved from Harvard's Health Publishing: https://www.health.harvard.edu/pain/acetaminophen-safety-be-cautious-but-not-afraid
4. John P. Cunha, D. F. (n.d.). ACETAMINOPHEN. Retrieved from RxList: https://www.rxlist.com/consumer_acetaminophen_tylenol/drugs-condition.htm
5. Omudhome Ogbru, P. (n.d.). Acetaminophen Uses, Side Effects, and Dosage. Retrieved from MedicineNet: https://www.medicinenet.com/acetaminophen/article.htm#what_is_acetaminophen_how_does_it_work_mechanism_of_action
6. Susan E Farrell, M., & Chief Editor: Michael A Miller, M. (2020, January 17). Acetaminophen Toxicity. Retrieved from Medscape: https://emedicine.medscape.com/article/820200-overview#a1

 

 

---

Find articles related to: Medicine Telehealth Health Acetaminophen Analgesic Antipyretic Acetaminophen Toxicity


More articles about Pain Management

Back to the Health Tips Index