Paracetamol is analgesic and antipyretic agent. Paracetamol is the active metabolite of phenacetin, responsible for its analgesic effect. Paracetamol is a weak prostaglandin inhibitor in peripheral tissues and possesses no significant antinflammatory effects. Paracetamol is one of the most important drug used for the treatment of mild to moderate pain when an antinfalmmatory effect is not necessary. Paracetamol is preferred over aspirin as an analgesic/antipyretic for patients in whom aspirin is contraindicated, such as those who have a history of gastric ulcer or a coagulation disorder.
2 Analgesics, antipyretics, NSAIDs, antigout, and antirheumatics 2.1 Non-opioid analgesics 2.1.2 Paracetamol
Paracetamol also known as Acetaminophen, Acetaminophen. . It is of Synthetic origin and belongs to Aminophenol. It belongs to Cyclo-oxygenase inhibitor pharmacological group on the basis of mechanism of action and also classified in Analgesics and Anti-inflammatory Agents pharmacological group.The Molecular Weight of Paracetamol is 151.20. Its pKa is 9.5.
Oral absorption of Paracetamol is found to be 96.5% ±1.5. Volume of distribution is found to be 0.9 l/kg and plasma protien binding is < 20%. Presystemic metabolism is noted to be 20% and metabolism is reported hepatic. Renal Excretion accounts for 5% unchanged and plasma half life is 1.5-3.0 hr.
Paracetamol is primarily indicated in conditions like
Ear pain, Fever, Headache, Malaise, Migraine, Mild to moderate pain, Pain, Post-vaccine reaction, Short-bowel syndrome, Tobacco amblyopia and leber's optic atrophy, Toothache.
Paracetamol is known to interact with other drugs, the details of drug interactions is as follows:
Drug Details Severity Onset Management Alcohol Ascorbic Acid Ascorbic acid increases half life of acetaminophen. Azilisartan Medoxomil Azilisartan when administered with NSAIDS (like paracetamol) can lead to volume depletion Busulphan Metabolism of Intravenous Busulphan possibly inhibited Paracetamol (caution is advised within 72 hours of Paracetamol). Carbamazepine plasma concentration of paracetamol may be reduced by anti epileptic such as carbamazepine, phenobarbital , phenytoin or primidone Minor Chloramphenicol Cimetidine (HCl) Diflunisal Interferon Alpha Isoniazid Isoniazid exacerbate the hepatotoxicity of acetaminophen by inducing its CYP450 2E1 metabolism results in toxic metabolites. Moderate Coadministration is considered contraindicated. Cmonitor the patient for hepatotoxicity. Aspirin is considered as safer alternative of paracetamol. Itopride (HCl) Metoclopramide (HCl) Probenecid pretreatment with probenecid can decrease paracetamol clearance and increase plasma half life
Minor Propantheline (Br) Propantheline decreases the gastrointestinal absorption of acetaminophen by reducing gastric motility and delaying gastric emptying. Minor Sulphinpyrazone Sulphinpyrazone increases the hepatotoxicity of paracetamol and decreases its pharmacological effect by accelerating the metabolism of paracetamol. Moderate Use of this combination should be avoided over a prolong period of time. Closely monior for hepatotoxicity. Warfarin (Na) Warfarin (Na) Paracetamol potentiate the hypoprothrombinemic effect of warfarin Minor Monitor signs of bleeding. Zidovudine Combined use of these agents may potentiate the risk of bone marrow suppression and hepatotoxicity. Minor Closely monitor the patient for the development hepatotoxicity and bone marrow toxicity.
These interactions are sometimes beneficial and sometimes may pose threats to life. Always consult your physician for the change of dose regimen or an alternative drug of choice that may strictly be required.
Interference in Pathology
False +ve results for plasma salicylates
The severe or irreversible adverse effects of Paracetamol, which give rise to further complications include Bronchospasm.
Paracetamol produces potentially life-threatening effects which include Blood dyscrasias, Centribular Necrosis, Liver damage. which are responsible for the discontinuation of Paracetamol therapy.
The signs and symptoms that are produced after the acute overdosage of Paracetamol include hypoglycemic coma, Hepatic necrosis, Liver failure, renal tubular necrosis.
The symptomatic adverse reactions produced by Paracetamol are more or less tolerable and if they become severe, they can be treated symptomatically, these include Skin rashes, GI adverse effects.
Click on the appropriate strength of the dosage form to view its available brands.
Single Ingredient Inj: 500 mg, 150 mg/ml, Inf: 1 g/100ml, Drops: 60 mg, 12 mg/ml, 100 mg/ml, 80 mg/0.8ml, Syrup: 250 mg/5ml, Susp: 50 mg/5ml, 120 mg/5ml, 250 mg/5ml, Elixir: 120 mg/5ml, Tabs: 125 mg, 200 mg, 250 mg, 300 mg, 325 mg, 450 mg, 500 mg, 650 mg, Suppositories: 125 mg, 250 mg, Multi ingredient
Inj: 150 mg/ml, Syrup: 80 mg/5ml, 100 mg/5ml, 120 mg/5ml, 160 mg/5ml, 200 mg/5ml, 250 mg/5ml, 325 mg/5ml, Susp: 120 mg/5ml, Elixir: 80 mg/5ml, 325 mg/15ml, Sachet: 100 mg, 500 mg, Tabs: 75 mg, 150 mg, 200 mg, 250 mg, 300 mg, 325 mg, 400 mg, 450 mg, 500 mg, 600 mg, 650 mg, Caps: 300 mg, 500 mg, Powder: 500 mg/sachet,
Paracetamol's dosage details are as follows:
500 to 1000 mg 750 (750) 6 hourly PO Maximum adult dose is 4 g/day in divided doses (i.e. 1g every 6 hourly)
Paedriatic Dosage ( 20 Kg. )
10 to 15 mg/kg/dose 12 (12.5) 6 hourly Oral
Neonatal Dosage ( 3 Kg. )
12 mg/kg 12 (12) 6 hourly Oral -
High Risk Groups
If prescribing authority justifies the benefits of the drug against the possible damages he/she should reevaluate them and consult the reference material and previous studies.
Warning / Precautions
If sensitivity reaction occurs, discontinue use of paracetamol. If pain persist more than 10 days and arthritic and rheumatic condition affecting children, immediately consult physician. If patient have been diagnosed with liver or kidney impairment, seek medical advice before taking medication. If symptoms persists consult doctor.
Store in a well closed container, Below 40°C. Protect from Sunlight and Moisture.
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