Product Information
Registration Status: ActiveMAXIGESIC TABLET 500MG/150MG is approved to be sold in Singapore with effective from 2014-10-23. It is marketed by APEX PHARMA MARKETING PTE LTD, with the registration number of SIN14648P.
This product contains Ibuprofen 150mg, and Paracetamol 500mg in the form of TABLET, FILM-COATED. It is approved for ORAL use.
This product is manufactured by SIGMA LABORATORIES LTD in INDIA.
It is an Over-the-counter Medicine that can be freely obtained from any retailer
Description
Ibuprofen, a propionic acid derivative, is a prototypical nonsteroidal anti-inflammatory agent (NSAIA) with analgesic and antipyretic properties.
Indication
For symptomatic treatment of rheumatoid arthritis, juvenile rheumatoid arthritis and osteoarthritis. May be used to treat mild to moderate pain and for the management of dysmenorrhea. May be used to reduce fever. Has been used with some success for treating ankylosing spondylitis, gout and psoriatic arthritis. May reduce pain, fever and inflammation of pericarditis. May be used IV with opiates to relieve moderate to severe pain. Ibuprofen lysine may be used IV to treat patent ductus arteriosus (PDA) in premature neonates.
Mechanism of Action
The exact mechanism of action of ibuprofen is unknown. Ibuprofen is a non-selective inhibitor of cyclooxygenase, an enzyme invovled in prostaglandin synthesis via the arachidonic acid pathway. Its pharmacological effects are believed to be due to inhibition cylooxygenase-2 (COX-2) which decreases the synthesis of prostaglandins involved in mediating inflammation, pain, fever and swelling. Antipyretic effects may be due to action on the hypothalamus, resulting in an increased peripheral blood flow, vasodilation, and subsequent heat dissipation. Inhibition of COX-1 is thought to cause some of the side effects of ibuprofen including GI ulceration. Ibuprofen is administered as a racemic mixture. The R-enantiomer undergoes extensive interconversion to the S-enantiomer in vivo. The S-enantiomer is believed to be the more pharmacologically active enantiomer.
Pharmacokinetics
- Absorption
- ~ 80% absorbed from GI tract
Time to reach peak plasma concentration = 47 minutes (suspension), 62 minutes (chewable tablets), 120 minutes (conventional tablets)
- Distribution
- Metabolism
- R-enanatiomer undergoes extensive enantiomeric conversion (53-65%) to the more active S-enantiomer in vivo. Metablized by oxidation to 2 inactive metabolites: (+)-2[4´-(2-hydroxy-2-methylpropyl)phenyl]propionic acid and (+)-2-[4´-(2-carboxypropyl)phenyl]propionic acid. Very small amounts of 1-hydroxyibuprofen and 3-hydroxyibuprofen have been recovered from urine. Cytochrome P450 2C9 is the major catalyst in the formation of oxidative metabolites. Oxidative metabolites may be conjugated to glucuronide prior to excretion.
- Elimination
Toxicity
Side effects: May cause peripheral edema and fluid retention. Use caution in patients with congestive heart failure or severe uncontrolled hypertension. May cause dyspepsia, heartburn, nausea, vomiting, anorexia, diarrhea, constipation, stomatitis, flatulence, bloating, epigastric pain, and abdominal pain. Peptic ulcer and GI bleeding have been reported. May also cause dizziness, headache and nervousness. Acute renal failure accompanied by acute tubular necrosis has been reported.
Most common symptoms of overdose are abdominal pain, nausea, vomiting, lethargy, vertigo, drowsiness (somnolence), dizziness and insomnia. Other symptoms of overdose include headache, loss of consciousness, tinnitus, CNS depression, convulsions and seizures. May rarely cause metabolic acidosis, abnormal hepatic function, hyperkalemia, renal failure, dyspnea, respiratory depression, coma, acute renal failure, and apnea (primarily in very young pediatric patients).
LD50=1255mg/kg(orally in mice)
Active Ingredient/Synonyms
(±)-2-(p-isobutylphenyl)propionic acid | (±)-ibuprofen | (±)-p-isobutylhydratropic acid | (±)-α-methyl-4-(2-methylpropyl)benzeneacetic acid | (4-isobutylphenyl)-α-methylacetic acid | (RS)-ibuprofen | 2-(4-isobutylphenyl)propanoic acid | 4-isobutylhydratropic acid | Ibuprophen | α-(4-isobutylphenyl)propionic acid | α-(p-isobutylphenyl)propionic acid | Ibuprofen |
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.
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.
Pharmacokinetics
- Absorption
- Rapid and almost complete
- Distribution
- 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
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.
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 |
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.