Trade Names:Mirena- Intrauterine device 52 mg (releases approximately 20 mcg/day)
Trade Names:Plan B- Tablets 0.75 mg
Trade Names:Plan B One-Step- Tablets 1.5 mg
Levonorgestrel is a progestogen that causes thickening of cervical mucus, inhibition of sperm capacitation or survival, and alteration of the endometrium. Levonorgestrel, as an emergency contraceptive, prevents ovulation or fertilization by altering tubal transport of sperm and/or ova, as well as inhibiting implantation by altering the endometrium.
Plasma levels are approximately 150 to 200 pg/mL after the first few weeks, and 180, 192, and 159 pg/mL after 12 mo, 24 mo, and 60 mo of use, respectively (intrauterine). Rapidly and completely absorbed after oral administration. Bioavailability is about 100% (oral). C max and T max are about 14.1 ng/mL and 1.6 h, respectively, for Plan B and 19.1 ng/mL and 1.7 h, respectively, for Plan B One-Step .
Plasma levels with the levonorgestrel-releasing intrauterine system do not display peaks and troughs. Approximately 50% is bound to albumin and 47.5% is bound to sex hormone–binding globulin. Vd is approximately 1.8 L/kg (oral).
Extensively metabolized to a large number of inactive metabolites.
The half-life is 17 h (after daily oral doses) (intrauterine), 24 h ( Plan B ), and 28 h ( Plan B One-Step ). Both the parent drug and its metabolites are primarily excreted in urine.
No formal studies.Hepatic Function Impairment
No formal studies.Race
There was a higher increase in the rate of pregnancy in Chinese women using Plan B One-Step ; the reason for this apparent increase is unknown.
Prevention of pregnancy (intrauterine); emergency contraceptive (oral).
Known or suspected pregnancy; hypersensitivity.Intrauterine system
Pregnancy or suspicion of pregnancy; congenital or acquired uterine anomaly, including fibroids if they distort the uterine cavity; acute pelvic inflammatory disease (PID) or history of PID unless there has been a subsequent intrauterine pregnancy; postpartum endometritis or infected abortion in past 3 mo; known or suspected uterine or cervical neoplasia or unresolved, abnormal Pap smear; genital bleeding of unknown etiology; untreated acute cervicitis or vaginitis, including bacterial vaginosis or other lower genital tract infection, until infection is controlled; acute liver disease or liver tumor (benign or malignant); conditions associated with increased susceptibility to pelvic infections; previously inserted intrauterine device that has not been removed; hypersensitivity to any component of this product; known or suspected carcinoma of the breast.
Insert into uterine cavity within 7 days of onset of menstruation or immediately after first-trimester abortion. Replace every 5 yr.Conversion to Other Birth Control Methods
If the patient has regular cycles, remove the intrauterine system during the first 7 days of the menstrual cycle and start the new birth control method.
If the patient has irregular cycles or amenorrhea, or if the intrauterine system is removed after the seventh day of the menstrual cycle, start the new method of birth control at least 7 days before removal of the intrauterine system.Plan BEmergency Contraception Adults and Children who have undergone menarche
PO 1 tablet (0.75 mg) as soon as possible within 72 h after unprotected intercourse; second tablet (0.75 mg) 12 h after the first dose.Plan B One-StepEmergency Contraception Adults and Children who have undergone menarche
PO 1 tablet (1.5 mg) as soon as possible within 72 h after unprotected intercourse or known or suspected contraceptive failure.
Store between 59° and 86°F.Plan B One-Step
Store between 68° and 77°F
Reduced contraceptive efficacy.Protease inhibitors/non-nucleoside reverse transcriptase inhibitors
Increase or decrease in the plasma levels of progestin has been noted.Warfarin
Anticoagulant activity may be enhanced.
Bradycardia, hypertension, syncope (intrauterine system).
Fatigue, headache (17%); dizziness (11%); decreased libido, nervousness (intrauterine system).
Acne; dermatitis; hirsutism; hypertrichosis; pain, itching, or infection near implant site; scalp hair loss.
Nausea (23%); abdominal pain (18%); vomiting (6%); diarrhea (5%); abdominal discomfort, change in appetite.
Heavier menstrual bleeding (31%); lighter menstrual bleeding (13%); breast tenderness (11%); delay of menses (5%); amenorrhea; cervicitis; dysmenorrheal; leukorrhea; oligomenorrhea; pelvic pain; prolonged, irregular, frequent, or scanty bleeding; spotting; vaginitis (postmarketing).
Sinusitis, upper respiratory tract infection (intrauterine system).
Adnexal enlargement, breast discharge, difficult removal, mastalgia, musculoskeletal pain.
Counsel patients that this product does not protect against HIV infection (AIDS) and other STDs.
Reexamine and evaluate patients 4 to 12 wk after insertion of the intrauterine system and once yearly thereafter, or more frequently if clinically indicated. Examine users with complaints of fever, genital lesions, pain, odorous discharge, sores, or unexplained bleeding. Evaluate patients with lower abdominal pain with or without missed periods and patients who develop vaginal bleeding and were previously amenorrheic for the possibility of ectopic pregnancy. Monitor blood glucose concentrations in patients with diabetes. Closely monitor patients on long-term corticosteroids and diabetic patients on insulin for infection. Monitor diabetic women while taking levonorgestrel.
Category X . Levonorgestrel is not effective in terminating an existing pregnancy.
Excreted in breast milk.
Use before menarche is not indicated.
Not intended for use in postmenopausal women.
About 80% of women wishing to become pregnant conceived within 12 mo after removal of the intrauterine system.
Use the intrauterine system with caution in patients who have a coagulopathy or are receiving anticoagulants; with marked increase in blood pressure; with severe arterial disease such as stroke or MI; who have migraine, focal migraine with asymmetrical visual loss, or other symptoms indicating transient cerebral ischemia; or who have exceptionally severe headache.
Most women can expect variation in menstrual bleeding patterns, ranging from heavy bleeding to amenorrhea.
Women who currently have or have had breast cancer should not use hormonal contraceptives. Spontaneous cases of breast cancer have been reported with the intrauterine system.
Levonorgestrel (oral) is not recommended for routine use as a contraceptive.
Follicle may grow beyond usual size and may resemble ovarian cyst.
May experience a slight deterioration in glucose tolerance, with increases in plasma insulin.
Have occurred, although relationship to drug is not established.
Embedment of the intrauterine system in the myometrium may occur, leading to decreased contraceptive effectiveness.
Partial or complete expulsion of the intrauterine system may occur.
Levonorgestrel may affect glucose tolerance.
Risk of septic abortion, miscarriage, premature delivery, premature labor, and sepsis may be increased with the intrauterine system. Remove intrauterine system if possible. Long-term effects on offspring are unknown.
Should occur for the following medical reasons: AIDS, endometrial or cervical malignancy, endometriosis, intractable pelvic pain, menorrhagia and/or metrorrhagia producing anemia, pelvic infection, pregnancy, severe dyspareunia, STD, symptomatic genital actinomycosis, or uterine or cervical perforation.
Syncope, bradycardia, or other neurovascular episodes may occur during insertion of the intrauterine system.
Use of intrauterine devices has been associated with an increased risk of PID.
Perforation of the uterus and cervix by the intrauterine system may occur.
Intrauterine system should not be inserted until 6 wk postpartum or until involution of the uterus is complete to reduce the incidence of perforation and expulsion.
Cases of group A streptococcal sepsis have occurred rarely in patients following insertion of the intrauterine system.
Levonorgestrel does not protect against HIV (AIDS) and other STDs.
Patients with certain types of valvular or congenital heart disease and surgically constructed systemic-pulmonary shunts are at increased risk of infective endocarditis, and use of the intrauterine system may represent a potential source of septic emboli.
Fluid retention, nausea, uterine bleeding irregularities, vomiting.
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