Levonorgestrel

A to Z Drug Facts

 Action Synthetic, biologically active progestin that transforms proliferative endometrium into secretory endometrium and inhibits secretion of pituitary gonadotropins, preventing follicular maturation and ovulation.

 Indications Prevention of pregnancy.

 Contraindications Subdermal implants: Active thrombophlebitis or thromboembolic disorders; undiagnosed abnormal genital bleeding; known or suspected pregnancy; acute liver disease; benign or malignant liver tumors; known or suspected carcinoma of breast. Intrauterine system: Pregnancy or suspicion of pregnancy; congenital or acquired uterine anomaly; 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 months; genital bleeding of unknown etiology; untreated acute cervicitis or vaginitis including bacterial vaginosis or other lower genital tract infection until infection is controlled; women or sexual partner has multiple sexual partners; conditions associated with increased susceptibility to infections with microorganisms (eg, leukemia, AIDS, IV drug use); genital actinomycosis; previously inserted IUD that has not been removed; known or suspected carcinoma of the breast; history of ectopic pregnancy or condition that would predispose to ectopic pregnancy; hypersensitivity to any component of this product.

 Route/Dosage

ADULTS: Subdermal 6 capsules inserted in midportion of upper arm during first 7 days of onset of menses. Remove after 5 yr.

Intrauterine system

ADULTS: Insert into uterine cavity within 7 days of onset of menstruation or immediately after first trimester abortion. Replace q 5 yr.

 Interactions

Carbamazepine: Reduced contraceptive efficacy. Phenytoin: Reduced contraceptive efficacy. Rifampin: Possible reduced contraceptive efficacy.

 Lab Test Interferences Endocrine tests may be affected. Sex hormone-binding globulin concentrations may be decreased; thyroxine concentrations may be slightly decreased and triiodothyronine uptake may be increased.

 Adverse Reactions

CV: Syncope, bradycardia, hypertension (intrauterine system). CNS: Headache; nervousness; dizziness; decreased libido (intrauterine system). DERM: Dermatitis; acne; hirsutism; hypertrichosis; scalp hair loss; pain, itching or infection near implant site. GI: Nausea; change in appetite; weight gain; abdominal discomfort. GU: Prolonged, irregular, frequent, or scanty bleeding; spotting; amenorrhea; cervicitis; leukorrhea; vaginitis. META: Weight gain. RESP: Upper respiratory infection, sinusitis (intrauterine system). OTHER: Adnexal enlargement; mastalgia; breast discharge; implant removal difficulty; musculoskeletal pain.

 Precautions

Pregnancy: Category X. Children: Safety and efficacy before menarche not established. Lactation: Excreted in breast milk. Bleeding irregularities: Most women can expect variation in menstrual bleeding patterns. Delayed follicular atresia: Follicle may grow beyond usual size and may resemble ovarian cyst. Ectopic pregnancies: Have occurred, although relationship to drug is not established. Intrauterine pregnancy: Risk of septic abortion, miscarriage, sepsis, premature labor, and premature delivery may be increased with the intrauterine system. Ocular lesions: Retinal thrombosis has occurred with oral contraceptives; consider possibility in levonorgestrel users. Perforation: Perforation of the uterus and cervix by the intrauterine system may occur. Thromboembolic disorders: Remove capsules if thrombophlebitis or thromboembolic disease occurs. Consider removal in patients immobilized for prolonged periods.

Valvular/Congenital heart disease: 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.

 Administration/Storage

• Capsules must be inserted only by physician trained in procedure.

 Assessment/Interventions

• Obtain patient history, including drug history and any known allergies. Note pregnancy and lactation status, current or past thrombophlebitis, abnormal menstrual or vaginal bleeding, cervical cytology, any degree of immobility, liver disease, breast abnormalities, or hyperlipedemia.
• Ensure that complete physical examination is performed before insertion and repeated annually during use. Obtain baseline weight.
• After insertion, monitor site for healing and absence of infection.

 Patient/Family Education

• Explain that contraceptive method will be effective for 5 yr; capsules should be removed after that period, but can be removed at any time; and that removal should be done by a physician trained in procedure.
• Encourage low-fat, low-cholesterol diet.
• Teach patient to identify and report signs of wound infection after insertion.
• Instruct patient to notify physician if capsule falls out.
• Instruct patient to report the following symptoms to physician: jaundice, fluid retention, depression, vision changes, abnormal bleeding, and weight gain.
• Emphasize that missed menstrual period is not an accurate indicator of pregnancy.
• Explain that menstrual irregularities are common, especially during first year of therapy.
• Emphasize importance of keeping follow-up visits to evaluate effectiveness of contraceptive therapy.

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Copyright © 2003 Facts and Comparisons
David S. Tatro
A to Z Drug Facts