Plasma progesterone levels after using high dose suppositories. A preliminary report.

Rectal administration of progesterone in relatively high doses is sometimes advocated for a few gynaecological disorders. Two different kinds of suppositories, containing 200 mg of active substance in a fatty base, were administered to six volunteers. The progesterone plasma concentrations, measured at I, 2 and 6 hours after administration, showed large interindividual differences. However, the average concentrations did not differ significantly between the two kinds of suppositories. The concentrations reached are in the order of magnitude of the normal top levels in the second half of the menstrual cycle.