Rapid onset of an increase in caffeine residence time in young women due to oral contraceptive steroids

Oral contraceptive steroids increased the residence time of caffeine in 9 young women by a factor of 2. The effect was already manifested during the first cycle 2 weeks after starting oral contraceptive steroids (OCS) and was slightly increased in the second cycle, after 6 weeks on OCS. Toxic effects attributed to oral contraceptive steroids may in part be indirect and due to prolonged retention of absorbed toxic agents to which women are exposed.Oral contraceptives (OCs) increased the residence time of caffeine in 9 young women by a factor of 2. The effect was already manifested during the 1st cycle 2 weeks after beginning OCs and was slightly increased in the 2nd cycle, after 6 weeks on OCs. Toxic effects attributed to OCs may in part be indirect and due to prolonged retention of absorbed toxic agents to which women are exposed.