Norgestrel(nor jess’ trel)
PREGNANCY CATEGORY X
Drug Classes
Hormonal contraceptive
Hormone
Progestin
Therapeutic Actions
Progestational agent; the endogenous female progestin, progesterone, transforms proliferative endometrium into secretory endometrium; inhibits the secretion of pituitary gonadotropins, which prevents follicular maturation and ovulation; and inhibits spontaneous uterine contractions. The primary mechanism by which norgestrel prevents conception is not known, but progestin-only hormonal contraceptives alter the cervical mucus, exert a progestational effect on the endometrium that interferes with implantation, and in some patients, suppress ovulation.
Indications
Prevention of pregnancy using hormonal contraceptives; somewhat less efficacious (3 pregnancies per 100 woman years) than the combined estrogen/progestin hormonal contraceptives (about 1 pregnancy per 100 woman years, depending on formulation)
Contraindications and Cautions
Contraindicated with allergy to progestins, tartrazine; thrombophlebitis, thromboembolic disorders, cerebral hemorrhage, or history of these conditions; CAD; hepatic disease; carcinoma of the breast or genital organs, undiagnosed vaginal bleeding, missed abortion; as a diagnostic test for pregnancy; pregnancy (fetal abnormalities—masculinization of the female fetus, congenital heart defects, and limb reduction defects); lactation.
Use cautiously with epilepsy, migraine, asthma, cardiac dysfunction, or renal impairment.
Available Forms
Tablets—0.075 mg
Dosages
Adults
Administer daily, starting on the first day of menstruation. Take one tablet, PO, at the same time each day, every day of the year. Missed dose: one tablet—take as soon as remembered, then take the next tablet at regular time; two consecutive tablets—take one of the missed tablets, discard the other, and take daily tablet at usual time; three consecutive tablets—discontinue immediately and use additional form of birth control until menses or pregnancy is ruled out.
Pharmacokinetics
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