Drug information of Acetaminophen

Mechanism of effect

Exhibits analgesic and antipyretic activity. Weak, reversible, isoform-nonspecific cyclooxygenase inhibitor at dosages of 1 g daily Inhibitory effect on cyclooxygenase-1 is limited; does not inhibit platelet function

Pharmacodynamic

Exhibits analgesic and antipyretic activity. Weak, reversible, isoform-nonspecific cyclooxygenase inhibitor at dosages of 1 g daily Inhibitory effect on cyclooxygenase-1 is limited; does not inhibit platelet function

Pharmacokinetics

Well absorbed following oral administration, with peak plasma concentration attained within 10–60 minutes (immediate-release preparations) or 60–120 minutes (extended-release preparations) Poor or variable absorption following rectal administration.
Food may delay absorption following administration as extended-release tablets.
Rapidly distributed to most body tissues. Crosses placenta and is distributed into breast milk.
Plasma Protein Binding:25% Metabolized principally by sulfate and glucuronide conjugation Mainly excreted in urine as conjugates.
Half-life:1.25–3 hours.

Drug indications

fever , Analgesic Activity

Dosage

*Pediatric Patients:Dosage in children should be guided by body weight.
--Pain:
-Oral Dose may be given every 4–6 hours as necessary (up to 5 times in 24 hours).
-Rectal Dose may be given every 4–6 hours as necessary (up to 5 times in 24 hours)
--Fever
-Oral Dose may be given every 4–6 hours as necessary (up to 5 times in 24 hours).
-- Rectal 325–650 mg every 4 hours as necessary
*Adults: Current limit is 4 g daily(oral or rectal)
--Pain Self-medication should not exceed 10 days
--Fever Self-medication should not exceed 3 days

Drug contraindications

hypersensitivity to drug or its components.

Side effects

nausea , decreased appetite , vomiting , rash , upper stomach pain , itching , acute pancreatitis

Interactions

Aripiprazole , Amitriptyline , Adefovir , Isoniazid , Imatinib , Phenobarbital , Phenytoin , Phenytoin phenobarbital , Warfarin , Hydroxyprogesterone Caproate , Desmopressin , Diphenhydramin , Digoxin , Risperidone , Cefalexin , Cisplatin , Cyclopentolate , Lactulose , Methimazole , Disulfiram , Zolmitriptan , probenecid , Vancomycin , Piperazine , cefepime , Tamoxifen , Mipomersen , Ethinyl Estradiol , Phenindione , Polyethylene glycol , Telmisartan , Methyclothiazide , Remdesivir , Blonanserin , Florbetapir F18

Alerts

1-Ingestion of a single toxic dose or multiple excessive doses can result in hepatotoxicity.
2- Serious, potentially fatal dermatologic reactions (e.g., Stevens-Johnson syndrome, toxic epidermal necrolysis, acute generalized exanthematous pustulosis) reported rarely.
3- Sensitivity reactions reported rarely.
4- Some formulations contain sulfites, which may cause allergic-type reactions

Points of recommendation

1-Risk of severe hepatic damage with use of excessive dosages, with concomitant use of multiple acetaminophen-containing preparations, and in those consuming substantial amounts of alcohol
2- When used for self-medication, importance of reading the product labeling
3- When used for self-medication in pediatric patients, importance of basing the dose on the child’s weight. importance of not exceeding the recommended daily dosage
4- Advise patients that paracetamol and APAP are other names for acetaminophen
5- Phenylketonuria:Children’s Tylenol and Junior Strength Tylenol chewable tablets contain aspartame (NutraSweet), which is metabolized in the GI tract to phenylalanine

Pregnancy level

B

Related drugs

Acetaminophen+codine , Acetaminophen+caffein+acetylsalic , Vitamin c+ASA