Fever Reducer & Pain Reliever (acetaminophen)
Last reviewed · Source: First Databank (FDB) drug data
Overview
Acetaminophen is a synthetic nonopiate derivative of p-aminophenol that produces analgesia and antipyresis.
Acetaminophen is a non-salicylate antipyretic and non-opioid analgesic agent. Acetaminophen produces analgesia and antipyresis in human and animal studies. Although the precise mechanism by which acetaminophen exerts its analgesic and antipyretic properties is not known, its primary activity is thought to occur centrally.
Individual doses of up to 3 grams and repeated doses of 1 gram of acetaminophen every 6 hours for 48 hours have not been shown to significantly impact platelet aggregation. Acetaminophen also does not have any immediate or delayed effects on small-vessel hemostasis. In patients with hemophilia treated with acetaminophen, there were no significant effects on bleeding time compared to healthy patients after multiple doses.
Following IV administration of single 500-mg, 650-mg, and 1-g doses of acetaminophen in adults, the pharmacokinetics are proportional to the dose administered. The peak plasma concentration of acetaminophen occurs at the end of the 15-minute IV infusion and is up to 70% higher than peak concentrations observed following oral administration of the same dose; however, systemic exposure to acetaminophen is similar following IV or oral administration. Following IV administration of a single dose of 15 mg/kg in pediatric patients or 1 g in adults, systemic exposure to acetaminophen is similar.
Acetaminophen plasma concentrations in neonates >32 weeks gestational age at birth receiving dosages of 12.5 mg/kg IV are similar to those in infants, children, and adolescents receiving dosages of 15 mg/kg IV, and adults receiving 1 g IV. Acetaminophen is widely distributed into most body tissues except fat. Acetaminophen is distributed into human milk in small quantities following oral administration.
About 10-25% of acetaminophen in blood is bound to plasma proteins.
Acetaminophen primarily undergoes metabolism via first-order kinetics that involves 3 separate pathways. These pathways include glucuronide conjugation, sulfate conjugation, and oxidation via the cytochrome P-450 (CYP) enzyme pathways, primarily CYP isoenzyme 2E1, to form a reactive intermediate metabolite N-acetyl-p-benzoquinone imine (NAPQI). At therapeutic doses, NAPQI is rapidly conjugated with glutathione and further metabolized to form cysteine and mercapturic acid conjugates.
Metabolites of acetaminophen are primarily excreted in the urine. Less than 5% of a dose of acetaminophen is excreted in urine as free acetaminophen and >90% of the dose is excreted within 24 hours after ingestion. Acetaminophen has been reported to have a plasma half-life of 2.4-3 hours in children, adolescents, and adults.
USES: This drug is used to treat mild to moderate pain (from headaches, menstrual periods, toothaches, backaches, osteoarthritis, or cold/flu aches and pains) and to reduce fever.
Generic name: acetaminophen
Pronunciation: (a-SEET-a-MIN-oh-fen)
Reference product & biosimilars
No reference, biosimilar or interchangeable associated with this drug.
Today’s intelligence on Fever Reducer & Pain Reliever
Indications
The following indications are listed for Fever Reducer & Pain Reliever:
- Arthritic Pain
- Back Pain
- Dysmenorrhea
- Fever
- Headache Disorder
- Myalgia
- Pain
- Toothache
Also known as: Aching Muscles, Cephalgia, Cephalodynia, Difficult Menses, Difficult Menstruation, Febrile, Febrile Reaction, Myalgic Pain, Myodynia, Painful Menses, Painful Menstrual Cramps, Pyrexia.
Dosing
To minimize risk of overdosage, recommended age-appropriate daily dosages of acetaminophen should not be exceeded.
Acetaminophen injection is administered by IV infusion over 15 minutes.
Acetaminophen is also commercially available in fixed-combination with ibuprofen (Combogesic(R)IV) for IV administration. See the full prescribing information for administration of this combination product.
Several commercially available fixed-combination prescription preparations containing acetaminophen are also available for oral use. See the full prescribing information for administration of these combination products.
Acetaminophen is commercially available in various oral and rectal over-the-counter (OTC) preparations as a single ingredient or in combination with other analgesics (e.g., ibuprofen), antihistamines, or decongestants. See the FDA Orange Book and the manufacturer's Drug Facts for further information.
No dosing information is available for this tab.
No dosing information is available for this tab.
Drug interactions
There is no enhanced messaging for this drug.
There are no contraindication interactions for this drug.
There are no severe interactions for this drug.
There are no moderate interactions for this drug.
Contraindications
*Known hypersensitivity to acetaminophen or any ingredient in the formulation.
*Severe hepatic impairment or severe active liver disease.
There are no contraindication contraindications for this drug.
There are no severe contraindications for this drug.
There are no moderate contraindications for this drug.
Adverse reactions
The most common adverse effects reported in clinical trials in >=5% of patients receiving IV acetaminophen were nausea, vomiting, headache, and insomnia in adults and nausea, vomiting, constipation, and pruritus in pediatric patients.
Common adverse effects associated with oral or rectal administration of acetaminophen include skin rash, hypersensitivity reactions, nephrotoxicity, and hematologic abnormalities (e.g., anemia, leukopenia, neutropenia, and pancytopenia).
There are no severe adverse reactions for this drug.
There are no less severe adverse reactions for this drug.
Precautions
No enhanced messaging available.
Use of IV acetaminophen for analgesia in pediatric patients >=2 years of age is supported by evidence from adequate and well-controlled studies of IV acetaminophen in adults and additional safety and pharmacokinetic data from 483 pediatric patients ranging in age from neonates to adolescents. Efficacy of IV acetaminophen for analgesia has not been established in pediatric patients <2 years of age.
Use of IV acetaminophen for fever in pediatric patients <2 years of age, including premature neonates (postmenstrual age of at least 32 weeks) is supported by evidence from adequate and well-controlled studies of IV acetaminophen in adults, clinical data in pediatric patients >=2 years of age, and additional safety and pharmacokinetic data from 239 patients <2 years of age, including neonates with a postmenstrual age of at least 32 weeks.
Epidemiologic data regarding oral acetaminophen use in pregnant females have shown no increased risk of major congenital malformations in infants exposed in utero to the medication. In a large population-based prospective cohort study involving more than 26,000 females with live-born singleton infants who were exposed to oral acetaminophen during the first trimester of pregnancy, no increase in the risk of congenital malformations was observed in exposed children compared with a control group of unexposed children; rate of congenital malformations (4.3%) was similar to the rate in the general population. A population-based, case-control study from the National Birth Defects Prevention Study also found no increase in the risk of major birth defects in a group of 11,610 children who had been exposed to acetaminophen during the first trimester of pregnancy compared with a control group of 4,500 children.
Animal reproduction studies in pregnant rats given oral acetaminophen during organogenesis at dosages up to 0.85 times the maximum recommended human daily dosage (4 g daily, based on body surface area comparison) showed evidence of fetotoxicity (reduced fetal weight and length) and a dose-related increase in bone variations (reduced ossification and rudimentary rib changes); the offspring showed no evidence of external, visceral, or skeletal malformations. When pregnant rats received oral acetaminophen throughout gestation at a dosage of 1.2 times the maximum recommended human daily dosage, areas of necrosis occurred in both the liver and kidney of pregnant rats and fetuses; these effects did not occur in animals given acetaminophen at dosages of 0.3 times the maximum recommended human dosage.
In a continuous breeding study in which pregnant mice were given acetaminophen at dosages approximately equivalent to 0.43, 0.87, or 1.7 times the maximum recommended human daily dosage (based on body surface area comparison), a dose-related reduction in body weight of the fourth and fifth litter offspring of the treated mating pair occurred during lactation and following weaning at all dosages studied. Animals receiving the highest dosage had a reduced number of litters per mating pair, male offspring with an increased percentage of abnormal sperm, and reduced birth weights in the next-generation pups.
The manufacturer states that there are no animal reproductive studies with IV acetaminophen.
A correlation between acetaminophen use during pregnancy and neurodevelopmental disorders in children, including autism and attention-deficit/hyperactivity disorder (ADHD), has been observed in studies; however, inconsistent findings have been reported in the literature and a causal relationship has not been established. Results of 2 high-quality studies with sibling controls indicate prenatal exposure to acetaminophen was not associated with an increased risk of a neurodevelopmental diagnosis. There are unmeasured familial confounding factors that may explain the apparent association observed in some studies. Acetaminophen is considered the preferred analgesic/antipyretic for use during pregnancy because of its relatively favorable safety profile compared with other common analgesics. The American College of Obstetricians and Gynecologists (ACOG) supports use of acetaminophen during pregnancy when taken as needed in moderation and after consultation with a doctor. There is no evidence to support any risk associated with appropriate use of acetaminophen during pregnancy. However, untreated maternal fever and pain pose risks such as neural tube defects and preterm birth, necessitating a balanced approach.
It is not known if IV acetaminophen is excreted into human milk; however, data suggest following oral administration of acetaminophen, infant exposure is approximately 1-2% of the weight-adjusted maternal daily dosage. Limited published studies report acetaminophen passes rapidly into human milk with similar levels noted in milk and plasma. A case of rash in a breast-fed infant has been reported; the rash resolved when the mother discontinued acetaminophen use and recurred when she resumed acetaminophen therapy. The developmental and health benefits of breast-feeding should be considered along with the mother's clinical need for acetaminophen and any potential adverse effects on the breast-fed infant from exposure to the medication or to the underlying maternal condition.
The manufacturer makes no specific dosage recommendations for geriatric patients. Although no overall differences in efficacy or safety were observed between geriatric and younger patients, and other clinical experience revealed no evidence of age-related differences, the possibility that some older patients may exhibit increased sensitivity to IV acetaminophen cannot be ruled out.
When the total number of patients studied in clinical trials of IV acetaminophen is considered, 15% were >=65 years of age, while 5% were >=75 years of age. Although no overall differences in efficacy or safety were observed between geriatric and younger patients, and other clinical experience revealed no evidence of age-related differences, the possibility some older patients may exhibit increased sensitivity to acetaminophen cannot be ruled out.
ICD codes
No ICD codes are available for this drug.
Formulary status
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Last reviewed · Source: First Databank (FDB) drug data
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