Category:
Analgesic; Antipyretic
Indication: accepted for pain ,arthritic, mild(treatment);or fever(treatment)-Acetaminophen is indicated to relieve mild or moderate pain and reduce fever . it provides symptomatic relief only ; additional therapy to treat the cause of the pain or fever should be instituted when necessary. Acetaminophen has minimal anti-inflammatory activity and does not relieve redness, swelling or stiffness due to arthritis ; it cannot be used in place of aspirin or other salicylates or other nonsteroidal anti-inflammatory drugs(NSAIDS) in the treatment of rheumatoid arthritis .
Pharmacology:
Analgesic: the mechanism of analgesic action has not fully determined acetaminophen may act
Predominantly by inhibiting prostaglandin synthesis in central nervous system(CNS) and to a lesser extent, through a peripheral action by blocking pain impulse generation .the peripheral action may also by blocking pain impulse generation. The peripheral action may also be due to inhibition of prostaglandin synthesis or to inhibition of synthesis or actions of other substances that sensitize pain receptors to mechanical or chemical stimulation.
Antipyretic; acetaminophen probably produce antiphrasis by acting centrally on the hypothalamic heat-regulating center to produce peripheral vasodilation resulting in increased blood flow through the skin , sweating, and heat loss. The central action probably involves inhibition of prostaglandin synthesis in the hypothalamus.
Pharmacokinetic/pharmacodinamic: rapid and almost complete; may be decreased if acetaminophen is taken following a high carbohydrate meal. Time to pick concentration 0.5-2 hours. Not significant with doses producing plasma concentrations below 60 mcg per ml may reach moderate levels with high or toxics Doses. Approximately 90to95 % of a dose to metabolized in the liver , half-life is 1to 4 hours ,time to pick concentration is 0.5 to 2 hours , peak plasma concentration 5-20mcg per ML with doses up to 650 mg ,time to peak effect 1to 3 hours, duration of action 3to4 and elimination is renal .
General Dosing information:
Usual adult and adolescent dose: as antipyretic and analgesic-325 to 500 mg every four hours, 650 to1gram every 6 hours as need or 1300mg every 8 hours while symptom persist.
Usual pediatric dose: as antipyretic and analgesic:
Infants up to 3 months of age-oral, 40mg every 4 hours as needed.
Infant 4 to 12months of age-oral, 80mg every 4 hours as needed
Children 1to 2 years of age –oral, 120mg every 4 hours as needed
Children 2 to 4 years of ages –oral 160mg every four hours as needed
Children 4-6 years of ages –oral 240mg every four hours as needed
Children 6-9 years of ages-oral 320mg every four hours as needed
Children 9-11 years of ages –oral 320 to 400 mg every four hours as needed
Children 11to 12 years of age -320 to 480 mg every four hours as needed
Precaution to consider; sensitive to acetaminophen and other ingredient that use in the tablet.
Pregnancy-problems in human have not been documented and it has been shown acetaminophen
Crosses the placenta.in breast- feeding problems have not been documented. Although peak concentrations of 10 to 15 mcg per Ml have been measured in breast milk.
Drug inter action and/or related problems : Alcohol ,especially chronic abuse of or hepatic enzyme inducer or hepatotoxic medications ,barbiturates or primidon,anticoagulants,cumarin , anti –inflammatory drugs, nonsteroidal (NSAID) or ASPRIN or other salicylates.
Side/adverse effects:
Agranulocytosis (fever with or without chills: soars, ulcers, or white spots on lips or in mouth: sore Throat): anemia(unusual tiredness or weakness): dermatitis, allergic(skin rash , hive or itching)hepatitis(yellow eye or skin): renal colic, renal failure(sudden decrease in amount of urine):thrombocytopenia