- Reduced incidence of cancer of the endometrium
- Reduced incidence of benign breast disease
- Reduced likelihood of functional ovarian cysts
- Less menstrual blood loss and more regular cycles
- Decreased severity of premenstrual syndrome and improvement in acne and
hirsutism (facial hair)
These potential benefits are balanced by a slightly increased risk of gallbladder disease,
hypertension, myocardial infarction, cerebral infarction, and pulmonary embolism. The
increased risk of stroke and heart attack associated with the “pill” is accentuated when
compounded by other risk factors, including smoking, migraine headaches, and advanc-
ing age. Indeed, convincing data support an upper age limit of 35 years for oral contra-
ceptive use by women who smoke.
5.9.1.2 Mini-Pill
A low dosage of progestin (“mini-pill”) is used, in the form of medroxyprogesterone
acetate, which is active at a very low dose. The mini-pill does not inhibit ovulation, but
rather interferes with the endometrium and the cervical mucus. The use of this pill pre-
vents most of the side effects of oral contraception, specifically nausea, water retention,
and in some cases thrombophlebitis. However, a lower success rate and other frequent
side effects have reduced the widespread acceptance of this preparation. Nevertheless,
the mini-pill has a role to play in certain specific situations. For example, in an uncom-
mon form of epilepsy called catamenial epilepsy, female patients will experience seizures
at particular times during their menstrual cycle, reflecting the fact that seizure focus is
stimulated by estrogens but inhibited by progestins. In such women, the mini-pill may
afford not only birth control but also improved seizure control.
5.9.1.3 “Morning After” Pill
This agent refers to the administration of a high dose of both an estrogen and a progestin.
Preferably, this is given 12–24 hr after coitus. The morning after pill induces menstrual
bleeding which in turn prevents the fertilized ovum from implanting. Alternatively,
implantation of the ovum can also be blocked with mifepristone, which is a progesterone
and glucocorticoid receptor antagonist; this agent induces a noninvasive abortion in early
pregnancy.
It is to be expected that these extremely widely used oral methods of contraception
will eventually be replaced by luteinizing hormone analogs as antiovulatory agents, or
possibly by immunological methods directed against human chorionic gonadotrophin
(hCG), which has both LH and FSH activity. Prostaglandins also show promise, and
reliable male contraception is also a future possibility.
5.10 STEROID HORMONES: SEX HORMONES—ANDROGENS
These steroids control the development of male characteristics: sperm production and
growth of the sex organs (penis, testes), prostate, and seminal vesicles (their androgenic
328 MEDICINAL CHEMISTRY