How does QS act as a contraceptive?
Quinacrine in the form of seven pellets is placed high in the uterus using a modified IUD inserter. Over the course of 30 minutes, the pellets dissolve in uterine fluid. A small portion of the fluid containing quinacrine makes its way a short distance into the fallopian tubes. About 30% of the quinacrine is excreted from the vagina and the rest is quickly absorbed from the uterus through blood vessels. This takes from one to four hours. The small amount entering the fallopian tubes injures their lining several cell layers deep. We do not yet understand the mechanism of the injury, which causes inflammation. The end result is formation of scar tissue. Each tube is blocked by a plug of scar tissue near its junction with the uterus. The egg cannot pass the point of blockage and is reabsorbed just like other cells. Normal ovulation continues until menopause. Surgical sterilization also produces scar tissue as a result of injury, blocking the tubes.
