DESCRIPTION
Ibuprofen -Ibuprofen, a propionic acid derivative, is a prototypical nonsteroidal anti-inflammatory agent (NSAIA) with analgesic and antipyretic properties. Paracetamol -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.
CATEGORIES
Ibuprofen -Anti-Inflammatory Agents, Non-Steroidal,Cyclooxygenase Inhibitors,Analgesics, Non-Narcotic. Paracetamol -Analgesics, Non-Narcotic,Antipyretics.
CHEMICAL FORMULA
Ibuprofen -C13H18O2, Paracetamol – C8H9NO2.
COMPOSITION
Ibubrufen 100mg + Paracetamol 162.5mg
INDICATION
Ibuprofen -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. Paracetamol – For temporary relief of fever, minor aches, and pains.
PHARMACODYNAMICS
Ibuprofen – Ibuprofen is a nonsteroidal anti-inflammatory agent (NSAIA) or nonsteroidal anti-inflammatory drug (NSAID), with analgesic and antipyretic properties. Ibuprofen has pharmacologic actions similar to those of other prototypical NSAIAs, which are thought to act through inhibition of prostaglandin synthesis. Paracetamol – 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.
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ABSORPTION
Ibuprofen -~ 80% absorbed from GI tract ,Time to reach peak plasma concentration = 47 minutes (suspension), 62 minutes (chewable tablets), 120 minutes (conventional tablets). Paracetamol – Rapid and almost complete.
METABOLISM
Ibuprofen -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. Paracetamol – 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
Ibuprofen – Ibuprofen is rapidly metabolized and eliminated in the urine. Paracetamol – Approximately 80% of acetaminophen is excreted in the urine after conjugation and about 3% is excreted unchanged.
HALF LIFE
Ibuprofen – 2-4 hours, Paracetamol – 1 to 4 hours.
TOXICITY
Ibuprofen -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), Paracetamol – 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.
SIDE EFFECTS
Ibuprofen -Belly pain. Upset stomach or throwing up. Many small meals, good mouth care, sucking hard, sugar-free candy, or chewing sugar-free gum may help. Loose stools (diarrhea). Hard stools (constipation). Drinking more liquids, working out, or adding fiber to your diet may help. Talk with your doctor about a stool softener or laxative. Paracetamol – Upset stomach or throwing up. Harm to the liver may rarely happen.