Dicofen Mechanism of Action

Pharmacology: Pharmacodynamics: Diclofenac is a nonsteroidal anti-inflammatory agents of the arylcarboxylic acid type derived from phenylacetic acid. It has the following activities: Anti-inflammatory, analgesic, antipyretic. It's mechanism of action is produced by inhibition of prostaglandin synthesis. It also exhibits an inhibitory action on platelet aggregation.
Pharmacokinetics: The pharmacokinetics of diclofenac is linear.
Diclofenac is totally and rapidly absorbed.
The C_maxis attained approximately 3.5 hrs or longer after oral administration of 100 mg SR and is maintained for >12 hrs. It is approximately 2 hrs after oral administration of 50 mg DR and it is approximately 20 min after IM injection of 75 mg and is maintained for >12 hrs. Due to a first passage hepatic clearance effect, some 50% of the orally absorbed dose of a DR tablet and some 60% of the orally absorbed dose of a SR tablet do not reach the systemic circulation. The area under the curve for the plasma concentration is approximately doubled following IM administration of an equivalent dose.
Repeated administration does not induce any accumulation phenomenon.
Protein binding exceeds 99%.
Synovial fluid concentrations reach a maximum 2-4 hrs after attainment of the plasma C_max.
These concentrations are higher than the plasma concentrations observed 4-6 hrs after administration and remain at this level for at least 12 hrs.
Plasma elimination half-life is 110 min. The plasma clearance rate is 263 mL/min in the synovial fluid; the apparent clearance half-life is 3-6 hrs.
90% of the administered oral or IV dose is excreted during a 96-hr period: 0.7% in unchanged form, 5-10% as conjugated product and 60% as conjugated hydroxylated compounds in the urine.
Metabolism involves direct conjugation, or oxidation in the 3' to 4' position of the dichlorophenyl nucleus or in position 5 of the phenyl nucleus linked to the acetic acid radical.
The major metabolite in man is 4'-hydroxydiclofenac.