DINDEVAN Tablet Ref.[9372] Active ingredients: Phenindione

Phenindione has been quantified by polarography, which has a limit of detection of 4mg/l. Following intravenous administration of 5mg/kg Phenindione to six subjects over a period of 2-3 months, the rate of decline in plasma levels of the drug averaged 10% per hour, corresponding to a half-life of 5-6 hours.

Absorption

Absorption of oral Phenindione in 12 subjects was rapid, with peak plasma levels being attained in 1-3 hours.

Distribution

In three subjects given the same dose intravenously, plasma levels were identical to those following oral administration, indicating complete absorption.

Biotransformation

Plasma levels of Phenindione following a single 400mg dose in 10 subjects were related to prothrombin response. There was a delay of 8-12 hours before any prothrombin response could be detected. All subjects showed a detectable prothrombin time increase within 24 hours. In 9 out of 10 subjects the prothrombin response was maximal two days after dosage, and in one subject three days after dosage.

Elimination

Prothrombin times in all 10 subjects did not return to control values until at least four days after dosage. Although there was no correlation among different individuals between the maximum prothrombin response and the plasma levels of phenindione, the duration of prothrombin response reflected the rate at which the drug disappeared from the plasma.

Following repeated dosage with 50-150mg per day for periods of three weeks to five months, no accumulations of phenindione was observed, although a satisfactory maintenance of prothrombin response was obtained.

No further relevant data.