Each tablet contains: Acetaminophen 500 mg Caffeine 65mg
Acetaminophen 4´-Hydroxyacetanilide; N-(4-Hydroxyphenyl)acetamide Molecular formula: C8H9NO2 =151.2 Caffeine Chemical name: 1,3,7-Trimethylpurine-2,6(3H,1H)-dione; 1,3,7-Trimethylxanthine; 7-Methyltheophylline Molecular formula: C8H10N4O2 =194.2
Mechanism of Action:
For acetaminophen: Analgesic : Acetaminophen may act predominantly by inhibiting prostaglandin synthesis in the central nervous system (CNS) and, to a lesser extent, through a peripheral action by blocking pain impulse generation. The peripheral action may also be due to inhibition of prostaglandin synthesis or to inhibition of the synthesis or actions of other substances that sensitize pain receptors to mechanical or chemical stimulation. Antipyretic : Acetaminophen probably produces antipyresis by acting centrally on the hypothalamic heat-requlating center. For caffeine : Caffeine is mild CNS stimulant. Caffeine – induced constriction of cerebral blood vessels, which leads to a decrease in cerebral blood flow and in the oxygen tension of the brain, may contribute to relief of some types of headache.
For acetaminophen: Absorption : Oral – Rapid and almost complete. Protein binding is not significant.. Approximately 9o to 95% of a dose is metabolized in the liver. Half-life is1 to 4 hours; does not change with renal failure but may be prolonged in acute overdosage . in some forms of hepatic disease, in the elderly , and in the neonate ; may be somewhat shortened in children. Peak plasma concentration is achieved after 0.5 to 2 hours and duration of action is 3 to 4 hours. Time to peak effect is 1 to 3 hours . Elimination is Renal , 3% of a dose may be excreted unchanged. In dialysis – Hemodialysis : 120 ml per minute ( for unmetabolized drug) ; metabolites are also cleared rapidly . Hemoperfusion : 200 ml per minute. Peritoneal dialysis : <10 ml per minute . (USP DI 2007) For caffeine : Absorption / Distribution – Caffeine is well absorbed orally (99%) and is widely distributed throughout the body. Metabolism/Excretion – Caffeine is metabolized in the liver and is excreted in the urine as methyluric acid, methylxanthine, and other metabolites with only approximately 1% excreted unchanged. In the adult, plasma half-life ranges from 3 to 7 hours. Half-life is increased with smoking and is prolonged in pregnancy (less than or equal to 18 hours), cirrhosis, and with concomitant use of some drugs. (Drug facts and comparisons 2007)
Pain, arthritic, mild (treatment);or Fever (treatment)-Acetaminophen/caffeine is indicated to relieve mild to moderate pain and reduce fever. chronic, high-dose acetaminophen therapy may require adjustment of anticoagulant dosage based on increased monitoring of prothrombin time in patients receiving a coumarin- or indandione-derivative anticoagulant.
Risk benefits should be considered when the following medical problems exists: ( ›› = major clinical significance ) ››Alcoholism , active or ››Hepatic desease or ››Viral hepatitis Increased risk of hepatotoxicity Phenylketonuria Renal function impairment, sever Risk of adverse renal effect may be increased with prolonged usage. Occasional use is acceptable. Sensitivity to acetaminophen or asprin.
Dosage and Administration:
For acetaminophen: Analgesic and Antipyretic – 1 tablet every three or four hours,or 2 tablets every six hours as needed, while symptoms persist . Note: For patient self-medication , it is recommended that a physician be consulted if pain is not relieved within ten days, fever within three days, or sore throat within two days . Usual adult prescribing limits : Up to 8 tablets daily.
Storage / Stability : Store in dry place, below 30° C. Avoid excessive heat or humidity .