PAMOL 650 TABLET 650MG

Paracetamol

Source of information: Drugbank (External Link). Last updated on: 3rd July 18
*Trade Name used in the content below may not be the same as the HSA-registered product.

Active Ingredient / Synonyms

4-(Acetylamino)phenol | 4-acetamidophenol | 4'-hydroxyacetanilide | Acenol | acetaminofén | Acetaminophen | acétaminophène | APAP | N-acetyl-p-aminophenol | p-acetamidophenol | p-acetaminophenol | p-Acetylaminophenol | p-hydroxy-acetanilid | p-hydroxyacetanilide | p-hydroxyphenolacetamide | Paracétamol | Paracetamol | Paracetamolum | Acetaminophen |

Description

Acetaminophen, also known as paracetamol, is commonly used for its analgesic and antipyretic effects. Its therapeutic effects are similar to salicylates, but it lacks anti-inflammatory, antiplatelet, and gastric ulcerative effects.

Indication

For temporary relief of fever, minor aches, and pains.

Mechanism of Action

Acetaminophen is thought to act primarily in the CNS, increasing the pain threshold by inhibiting both isoforms of cyclooxygenase, COX-1, COX-2, and COX-3 enzymes involved in prostaglandin (PG) synthesis. Unlike NSAIDs, acetaminophen does not inhibit cyclooxygenase in peripheral tissues and, thus, has no peripheral anti-inflammatory affects. While aspirin acts as an irreversible inhibitor of COX and directly blocks the enzyme's active site, studies have found that acetaminophen indirectly blocks COX, and that this blockade is ineffective in the presence of peroxides. This might explain why acetaminophen is effective in the central nervous system and in endothelial cells but not in platelets and immune cells which have high levels of peroxides. Studies also report data suggesting that acetaminophen selectively blocks a variant of the COX enzyme that is different from the known variants COX-1 and COX-2. This enzyme is now referred to as COX-3. Its exact mechanism of action is still poorly understood, but future research may provide further insight into how it works. The antipyretic properties of acetaminophen are likely due to direct effects on the heat-regulating centres of the hypothalamus resulting in peripheral vasodilation, sweating and hence heat dissipation.

Pharmacodynamics

Acetaminophen (USAN) or Paracetamol (INN) is a widely used analgesic and antipyretic drug that is used for the relief of fever, headaches, and other minor aches and pains. It is a major ingredient in numerous cold and flu medications and many prescription analgesics. It is extremely safe in standard doses, but because of its wide availability, deliberate or accidental overdoses are not uncommon. Acetaminophen, unlike other common analgesics such as aspirin and ibuprofen, has no anti-inflammatory properties or effects on platelet function, and it is not a member of the class of drugs known as non-steroidal anti-inflammatory drugs or NSAIDs. At therapeutic doses acetaminophen does not irritate the lining of the stomach nor affect blood coagulation, kidney function, or the fetal ductus arteriosus (as NSAIDs can). Like NSAIDs and unlike opioid analgesics, acetaminophen does not cause euphoria or alter mood in any way. Acetaminophen and NSAIDs have the benefit of being completely free of problems with addiction, dependence, tolerance and withdrawal. Acetaminophen is used on its own or in combination with pseudoephedrine, dextromethorphan, chlorpheniramine, diphenhydramine, doxylamine, codeine, hydrocodone, or oxycodone.

Pharmacokinetics

Absorption:

Rapid and almost complete

Distribution:

Not Available

Metabolism:

Acetaminophen primarily undergoes glucuronidation (45-55% of the dose) in which this process is facilitated by UGT1A1, UGT1A6, UGT1A9, UGT2B15 in the liver or UGT1A10 in the gut. 30-35% of the dose undergoes sulfation. This biotransformation is facilitated by SULT1A1, SULT1A3, SULT1A4, SULT1E1 and SULT2A1. A small percentage of acetaminophen is oxidized by CYP2E1 to form N-acetyl-p-benzo-quinone imine (NAPQI), a toxic metabolite which is then conjugated to glutathione and excreted renally. Studies suggest that CYP3A4 and CYP2E1 are the primary cytochrome P450 isozymes responsible for the generation of toxic metabolites. Accumulation of NAPQI may occur if primary metabolic pathways are saturated.

Elimination:

Approximately 80% of acetaminophen is excreted in the urine after conjugation and about 3% is excreted unchanged.

Half-life

1 to 4 hours

Clearance

Not Available

Toxicity

Oral, mouse: LD50 = 338 mg/kg; Oral, rat: LD50 = 1944 mg/kg. Acetaminophen is metabolized primarily in the liver, where most of it is converted to inactive compounds by conjugation with glucuronic acid and, to a lesser extent, sulfuric acid. Conjugates are then excreted by the kidneys. Only a small portion is excreted in unchanged in urine or oxidized via the hepatic cytochrome P450 enzyme system (CYP2E1). Metabolism via CYP2E1 produces a toxic metabolite, N-acetyl-p-benzoquinoneimine (NAPQI). The toxic effects of acetaminophen are due to NAPQI, not acetaminophen itself nor any of the major metabolites. At therapeutic doses, NAPQI reacts with the sulfhydryl group of glutathione to produce a non-toxic conjugate that is excreted by the kidneys. High doses of acetaminophen may cause glutathione depletion, accumulation of NAPQI and hepatic necrosis. The maximum daily dose of acetaminophen is 4 g. Liver failure has been observed at doses as low as 6 g per day. As such, the maximum daily and single dose of acetaminophen is currently being reviewed in some countries. N-acetyl-cysteine, a precursor of glutathione, may be administered in the event of acetaminophen toxicity.

References

  1. Health Science Authority of Singapore - Reclassified POM
  2. Drugbank

Although best effort has been made to ensure the information provided is correct and updated, users are advised to visit HSA Official website whenever in doubt. Please see Disclaimers.
We welcome all the content error reporting/feedback. Please contact us @ Text Us!

Approval Information

PAMOL 650 TABLET 650MG was registered with Health Science Authority of Singapore by SUNWARD PHARMACEUTICAL PTE LTD. It is marketed with the registration number of SIN15037P with effective from 2016-06-22.

This product contains 650MG of Paracetamol in the form of ORAL TABLET.

The medicine was manufactured by SUNWARD PHARMACEUTICAL SDN BHD in MALAYSIA

It is a an Over-the-counter Medicine which can be freely obtained from any retailer

Anatomical Therapeutic Chemical (ATC) Classification

ATC Code: N02BE01

Products Containing as Single Ingredient

Drug IDTrade NameActive IngredientsForensic ClassRegistrantStatus
1DEXTROMETHORPHAN LINCTUS 15mg/5mlDextromethorphanP OnlyDRUG HOUSES OF AUSTRALIA PTE LTDActive
22ZENMOLIN SYRUP 2mg/5mlSalbutamolP OnlyDRUG HOUSES OF AUSTRALIA PTE LTDActive
41APO-PROPRANOLOL TABLET 40mgPropranololPOMPHARMAFORTE SINGAPORE PTE LTDActive
42APO-DIAZEPAM TABLET 2mgDiazepamPOMPHARMAFORTE SINGAPORE PTE LTDActive
44APO-DIAZEPAM TABLET 5mgDiazepamPOMPHARMAFORTE SINGAPORE PTE LTDActive
45APO-DIAZEPAM TABLET 10mgDiazepamPOMPHARMAFORTE SINGAPORE PTE LTDActive
46APO-PROPRANOLOL TABLET 10mgPropranololPOMPHARMAFORTE SINGAPORE PTE LTDActive
55APO-ISDN TABLET 10mgIsosorbide DinitratePOMPHARMAFORTE SINGAPORE PTE LTDActive
63DIAPO TABLET 10mgDiazepamPOMBEACONS PHARMACEUTICALS PTE LTDActive
64FURMIDE TABLET 40mgFurosemidePOMBEACONS PHARMACEUTICALS PTE LTDActive

Products Containing as Mixture Ingredient

Drug IDTrade NameActive IngredientsForensic ClassRegistrantStatus
4DIPHENHYDRAMINE EXPECTORANTAmmonium Chloride|Diphenhydramine|Sodium CitrateP OnlyDRUG HOUSES OF AUSTRALIA PTE LTDActive
5DIPHENHYDRAMINE EXPECTORANT PAED.Ammonium Chloride|Diphenhydramine|Sodium CitrateP OnlyDRUG HOUSES OF AUSTRALIA PTE LTDActive
400FAKTU SUPPOSITORYCinchocaine|PolicresulenP OnlyTAKEDA PHARMACEUTICALS (ASIA PACIFIC) PTE LTDActive
407TRIMAXAZOLE TABLETSulfamethoxazole|TrimethoprimPOMBEACONS PHARMACEUTICALS PTE LTDActive
435APO-SULFATRIM TABLETSulfamethoxazole|TrimethoprimPOMPHARMAFORTE SINGAPORE PTE LTDActive
508APO-SULFATRIM PEDIATRIC TABLETSulfamethoxazole|TrimethoprimPOMPHARMAFORTE SINGAPORE PTE LTDActive
526B.S. SUSPENSIONSulfamethoxazole|TrimethoprimPOMAPEX PHARMA MARKETING PTE LTDActive
583CO-TRIMEXAZOLE SUSPENSIONSulfamethoxazole|TrimethoprimPOMBEACONS PHARMACEUTICALS PTE LTDActive
676BANEOCIN OINTMENTBacitracin|NeomycinPOMNOVARTIS (SINGAPORE) PTE LTDActive
678BANEOCIN POWDERBacitracin|NeomycinPOMNOVARTIS (SINGAPORE) PTE LTDActive