| Indication |
For use as a female contraceptive (depot). |
| Pharmacodynamics |
Etonogestrel is used as a female contraceptive. Etonogestrel is a
progestin or a synthetic form of the naturally occurring female sex
hormone, progesterone. In a woman's normal menstrual cycle, an egg
matures and is released from the ovaries (ovulation). The ovary then
produces progesterone, preventing the release of further eggs and
priming the lining of the womb for a possible pregnancy. If pregnancy
occurs, progesterone levels in the body remain high, maintaining the
womb lining. If pregnancy does not occur, progesterone levels in the
body fall, resulting in a menstrual period. Etonogestrel tricks the body
processes into thinking that ovulation has already occurred, by
maintaining high levels of the synthetic progesterone. This prevents the
release of eggs from the ovaries. |
| Mechanism of action |
Etonogestrel binds to the progesterone and estrogen receptors.
Target cells include the female reproductive tract, the mammary gland,
the hypothalamus, and the pituitary. Once bound to the receptor,
progestins like etonogestrel will slow the frequency of release of
gonadotropin releasing hormone (GnRH) from the hypothalamus and blunt
the pre-ovulatory LH (luteinizing hormone) surge. |
| Absorption |
Not Available |
| Volume of distribution |
|
| Protein binding |
Not Available |
| Metabolism |
Hepatic. |
| Route of elimination |
Excretion of ENG and its metabolites, either as free steroid or as
conjugates, is mainly in urine and to a lesser extent in feces. |
| Half life |
25 hours |
| Clearance |
Not Available |
| Toxicity |
Symptoms of overdose include nausea, vomiting, vaginal bleeding, and other menstrual irregularities. |
