Lybrel

Lybrel is part of the drug class:

• Natural and semisynthetic estrogens, plain

Mode of Action

Combination oral contraceptives act by suppression of gonadotropins. Although the primary mechanism of this action is inhibition of ovulation, other alterations include changes in the cervical mucus (which increase the difficulty of sperm entry into the uterus) and the endometrium (which reduce the likelihood of implantation).

Pharmacokinetics

No specific investigation of the absolute bioavailability of Lybrel in humans has been conducted. However, literature indicates that levonorgestrel is rapidly and completely absorbed after oral administration (bioavailability about 100%) and is not subject to first-pass metabolism. Ethinyl estradiol is rapidly and almost completely absorbed from the gastrointestinal tract but, due to first-pass metabolism in gut mucosa and liver, the bioavailability of ethinyl estradiol is between 38% and 48%.

A summary of the single dose and multiple dose levonorgestrel and ethinyl estradiol pharmacokinetic parameters for 18 women under fasting conditions is provided in Table 1. The plasma concentrations of levonorgestrel and ethinyl estradiol reached steady-state by approximately day 14. Levonorgestrel and ethinyl estradiol concentrations did not increase from days 14 to 28, but did increase from days 1 to 28.

The mean plasma concentrations of levonorgestrel and ethinyl estradiol following single (day 1) and multiple (days 14 and 28) oral administrations of levonorgestrel 90 mcg in combination with ethinyl estradiol 20 mcg to 18 healthy women is provided in Figure 1.

Figure 1: Mean Plasma ± SD† Concentrations of Levonorgestrel and Ethinyl Estradiol Following Single (Day 1) and Multiple (Days 14 and 28) Oral Administrations of Levonorgestrel 90 mcg in Combination with Ethinyl Estradiol 20 mcg to Healthy Women

The effect of food on the rate and the extent of levonorgestrel and ethinyl estradiol absorption following oral administration of Lybrel has not been evaluated.

Levonorgestrel in serum is primarily bound to sex hormone-binding globulin (SHBG). Ethinyl estradiol is about 97% bound to serum albumin. Ethinyl estradiol does not bind to SHBG, but induces SHBG synthesis.

Levonorgestrel: The most important metabolic pathways are reduction of the Δ4-3-oxo group and hydroxylation at positions 2α, 1β, and 16β, followed by conjugation. Most of the circulating metabolites are sulfates of 3α, 5β-tetrahydro-levonorgestrel, while excretion occurs predominantly in the form of glucuronides. Some of the parent levonorgestrel also circulates as 17β-sulfate. Metabolic clearance rates may differ among individuals by several-fold, and this may account in part for the wide variation observed in levonorgestrel concentrations among users.

Ethinyl estradiol: Cytochrome P450 enzymes (CYP3A4) in the liver are responsible for the 2‑hydroxylation that is the major oxidative reaction. The 2-hydroxy metabolite is further transformed by methylation, sulfation, and glucuronidation prior to urinary and fecal excretion. Levels of CYP3A4 vary widely among individuals and can explain the variation in rates of ethinyl estradiol 2-hydroxylation.

The terminal elimination half-life for levonorgestrel in Lybrel is about 36 hours. Levonorgestrel and its metabolites are excreted in the urine (40% to 68%) and in feces (16% to 48%). The terminal elimination half-life of ethinyl estradiol in Lybrel is about 21 hours.

Ethinyl estradiol is excreted in the urine and feces as glucuronide and sulfate conjugates and undergoes enterohepatic recirculation.

Special Populations

No formal studies on the effect of race on the pharmacokinetic parameters of Lybrel were conducted.

No formal studies have evaluated the effect of hepatic disease on the disposition of Lybrel. However, steroid hormones may be poorly metabolized in patients with impaired liver function.

No formal studies have evaluated the effect of renal disease on the disposition of Lybrel.

See PRECAUTIONS section - Drug Interactions.

An increased risk of the following serious adverse reactions (see WARNINGS section for additional information) has been associated with the use of oral contraceptives:

Thromboembolic and thrombotic disorders and other vascular problems (including thrombophlebitis and venous thrombosis with or without pulmonary embolism, mesenteric thrombosis, arterial thromboembolism, myocardial infarction, cerebral hemorrhage, cerebral thrombosis, transient ischemic attack), carcinoma of the reproductive organs and breasts, hepatic neoplasia/liver disease (including hepatic adenomas or benign liver tumors), ocular lesions (including retinal vascular thrombosis), gallbladder disease, carbohydrate and lipid effects, elevated blood pressure, and headache including migraine.

The following adverse reactions have been reported in patients receiving oral contraceptives and are believed to be drug related (alphabetically listed):

Acne

Amenorrhea

Anaphylactic/anaphylactoid reactions, including urticaria, angioedema, and severe reactions with respiratory and circulatory symptoms

Breast changes: tenderness, pain, enlargement, secretion

Budd-Chiari syndrome

Cervical erosion and secretion, change in

Cholestatic jaundice

Chorea, exacerbation of

Colitis

Contact lenses, intolerance to

Corneal curvature (steepening), change in

Dizziness

Edema/fluid retention

Erythema multiforme

Erythema nodosum

Focal nodular hyperplasia

Gastrointestinal symptoms (such as abdominal pain, cramps, and bloating)

Hirsutism

Infertility after discontinuation of treatment, temporary

Lactation, diminution in, when given immediately postpartum

Libido, change in

Melasma/chloasma which may persist

Menstrual flow, change in

Mood changes, including depression

Nausea

Nervousness

Pancreatitis

Porphyria, exacerbation of

Rash (allergic)

Scalp hair, loss of

Serum folate levels, decrease in

Spotting

Systemic lupus erythematosus, exacerbation of

Unscheduled bleeding

Vaginitis, including candidiasis

Varicose veins, aggravation of

Vomiting

Weight or appetite (increase or decrease), change in

The following adverse reactions have been reported in users of oral contraceptives:

Cataracts

Cystitis-like syndrome

Dysmenorrhea

Hemolytic uremic syndrome

Hemorrhagic eruption

Optic neuritis, which may lead to partial or complete loss of vision

Premenstrual syndrome

Renal function, impaired

Do not use Lybrel if you are pregnant or if you have recently had a baby. You should not take Lybrel if you have any of the following conditions: uncontrolled high blood pressure, heart disease, a blood-clotting disorder, circulation problems, diabetic problems with your eyes or kidneys, unusual vaginal bleeding, liver disease or liver cancer, severe migraine headaches, if you smoke and are over 35, or if you have ever had breast or uterine cancer, jaundice caused by birth control pills, a heart attack, a stroke, or a blood clot.

You may need to use back up birth control, such as condoms or a spermicide, when you first start using Lybrel or if you miss a dose. Follow your doctor's instructions.

Missing a pill increases your risk of becoming pregnant. Carefully follow the "missed dose" instructions if you forget to take a Lybrel pill.

Some drugs can make Lybrel less effective in preventing pregnancy, including antibiotics, hepatitis C medications, HIV/AIDS medications, seizure medications, or barbiturate sedatives. Tell your doctor about all other medications you use.

Lybrel can cause birth defects. Do not use if you are pregnant. Tell your doctor right away if you become pregnant, or if you miss two menstrual periods in a row. If you have recently had a baby, wait at least 4 weeks before taking Lybrel. You should not take Lybrel if you have:

• untreated or uncontrolled high blood pressure;

• heart disease (coronary artery disease, uncontrolled heart valve disorder, history of heart attack, stroke, or blood clot);

• a blood-clotting disorder or circulation problems;

• problems with your eyes, kidneys or circulation caused by diabetes;

• a history of hormone-related cancer such as breast or uterine cancer;

• unusual vaginal bleeding that has not been checked by a doctor;

• liver disease or liver cancer;

• severe migraine headaches (with aura, numbness, weakness, or vision changes), especially if you are older than 35;

• a history of jaundice caused by pregnancy or birth control pills; or

• if you smoke and are over 35 years old.

To make sure you can safely take Lybrel, tell your doctor if you have any of these other conditions:

• high blood pressure, varicose veins;

• high cholesterol or triglycerides, or if you are overweight;

• a history of depression;

• underactive thyroid;

• gallbladder disease;

• diabetes;

• seizures or epilepsy;

• a history of irregular menstrual cycles;

• tuberculosis; or

• a history of fibrocystic breast disease, lumps, nodules, or an abnormal mammogram.

The hormones in Lybrel (ethinyl estradiol and levonorgestrel) can pass into breast milk and may harm a nursing baby. Lybrel may also slow breast milk production. Do not Lybrel use if you are breast feeding a baby.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. Overdose symptoms may include nausea, vomiting, and vaginal bleeding.

Some drugs can make Lybrel less effective, which may result in pregnancy. Before using Lybrel, tell your doctor if you are using any of the following drugs:

• bosentan (Tracleer);

• an antibiotic or tuberculosis medication;

• drugs to treat hepatitis C, HIV, or AIDS;

• phenobarbital (Solfoton) and other barbiturates;

• St. John's wort; or

• seizure medications.

Tell your doctor about all other medicines you use, especially:

• dantrolene (Dantrium);

• tizanidine (Zanaflex); or

• tranexamic acid (Cyklokapron, Lysteda).

This list is not complete and other drugs may interact with Lybrel. Tell your doctor about all medications you use. This includes prescription, over-the-counter, vitamin, and herbal products. Do not start a new medication without telling your doctor.

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

• Feeling more or less hungry.
• Dizziness.
• Weight gain.
• Headache.
• Upset stomach or throwing up.
• Cramps.
• Bloating.
• Enlarged breasts.
• Breast soreness.
• Hair loss.
• Pimples (acne).
• Period (menstrual) changes. These include spotting or bleeding between cycles.
• Lowered interest in sex.
• This drug may cause dark patches of skin on your face. Avoid sun, sunlamps, and tanning beds. Use sunscreen and wear clothing and eyewear that protects you from the sun.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-FDA-1088. You may also report side effects at http://www.fda.gov/medwatch.

Applies to ethinyl estradiol / levonorgestrel: oral tablet

Cardiovascular

Cardiovascular side effects of hypertension and edema have been attributed to the estrogen component of this combination product. Significant blood pressure increases generally occurred only in women receiving high-dose estrogen products (50 mcg or more of ethinyl estradiol or equivalent daily). Exogenous estrogens may exert cardioprotective effects due to favorable changes in lipid profiles, however, beneficial effects may be partially or completely offset by alterations in lipid profiles induced by exogenous progestins.[Ref]

Detailed information concerning the effects of oral contraceptive therapy on lipid metabolism is available in the Endocrine paragraph of this side effect monograph.

Early investigations of high dose estrogen combinations (50 mcg or more of ethinyl estradiol or equivalent daily) suggested that women may be at increased risk of cardiovascular complications (myocardial infarction, stroke, and vascular thrombosis, including venous thromboembolism). More recent investigations of low dose estrogen combinations have suggested that oral contraceptive use is not associated with an increased risk of serious cardiovascular complications in healthy non smoking women up to the age of 45. Oral contraceptive use for women aged 35 to 44 who smoke or who have preexisting systemic diseases that may affect the cardiovascular system is not recommended.

Some investigators have suggested that even low dose products may result in adverse lipid metabolism and a woman's cardiovascular risk factors should be assessed before a decision is made to use oral contraceptive combinations.

The frequency of both subarachnoid hemorrhage and thrombotic stroke has been increased in women taking oral contraceptive hormones, however, the risk of these effects with low dose formulations appear to be very small for young women without underlying cardiovascular disease or other risk factors.[Ref]

General

Women taking oral contraceptive combinations have experienced several noncontraceptive health benefits. These benefits have included protection against two malignant neoplasms (endometrial carcinoma and ovarian cancer). In addition, use of oral contraceptive combinations has decreased the frequency of benign breast tumors, the risk of ovarian cysts, the risk of ectopic pregnancy, menstrual irregularity, the incidences of iron deficiency anemia, dysmenorrhea, and pelvic inflammatory disease.

Many of the adverse effects experienced by women on oral contraceptive combination products are related to a relative excess or deficiency of the estrogen and progestin components of these formulations. The following categorizes many of the frequent adverse effects by relative excess or deficiency of these components.

Progestin Excess:

Acne, oily skin
Breast tenderness
Depression
Tiredness, fatigue
Hair loss
Hypertension
Increased appetite
Weight gain
Cholestatic jaundice

Progestin Deficiency:

Late breakthrough bleeding
Amenorrhea
Hypermenorrhea

Estrogen Excess:

Nausea
Headache
Melasma
Hypertension
Breast tenderness
Edema

Estrogen Deficiency:

Early/midcycle breakthrough bleeding
Increased spotting
Hypomenorrhea[Ref]

A number of studies have suggested that use of oral contraceptives decreased the risk of ovarian cancer. Specifically, the risk of epithelial ovarian cancers is decreased by 40%. The protection against ovarian cancer may last for 10 to 15 years after discontinuation of oral contraceptives. After long term use (12 years), the risk of ovarian cancer is decreased by as much as 80%.

The risk of endometrial cancer is decreased by approximately 50%. Protection may last for 15 years after discontinuation and may be greatest for nulliparous women who may be at higher risk for endometrial carcinoma than other women.

The incidence of hospitalization for pelvic inflammatory disease has been approximately 50% lower in women taking oral contraceptives. The reason for the decrease in the frequency (or severity) of pelvic inflammatory disease in women taking oral contraceptives has not been fully elucidated.

Some recent studies have suggested that the decrease in frequency of functional ovarian cysts reported with some older formulations may not occur in women taking newer low dose formulations.

One recent study (The Nurses' Health Study) has suggested that long term use of oral contraceptives is safe and does not adversely affect long term risk for mortality.[Ref]

Gastrointestinal

Nausea, a relatively common gastrointestinal side effect, has occurred in approximately 10% of treated women during the first cycles of therapy. Some early reports suggested an association between oral contraceptive use and gallbladder disease.[Ref]

Cases of oral contraceptive induced esophageal ulceration and geographic tongue have been reported rarely.

More recent studies have suggested that the risk of gallbladder disease is minimal.[Ref]

Oncologic

Oral contraceptive combinations have been studied extensively for oncologic side effects. A number of studies have examined a possible relationship between the use of oral contraceptives and the development of breast cancer. Many of the studies have reported conflicting results. A committee of the World Health Organization evaluated these studies and the risks of breast cancer and concluded that: "Numerous studies have found no overall association between oral contraceptive use and risk of breast cancer." In addition, the same committee also examined a possible relationship between oral contraceptive use and neoplasms of the uterine cervix and concluded that: "There are insufficient data to draw any firm conclusions regarding the effects of combined oral contraceptives on the risk of cervical adenocarcinoma."[Ref]

The World Health Organization committee also noted that some studies "have found a weak association between long-term use of oral contraceptives and breast cancer diagnosed before the age of 36, and perhaps up to the age 45....It is unclear whether this observed association is attributable to bias, the development of new cases of cancer, or accelerated growth of existing cancers."

The World Health Organization committee further concluded that there is no increased risk of breast cancer in women over the age of 45 who have previously taken oral contraceptives. In addition, studies suggest that use of oral contraceptives does not place specific groups of women (like those with a family history of breast cancer) at higher or lower risk, and variations in the hormonal content of oral contraceptives do not influence the risk of breast cancer.

In general, studies evaluating the potential risk of cervical cancer in patients taking oral contraceptives have been complicated by the large number of confounding factors which make investigations into the epidemiology of this neoplasm difficult. Some studies have suggested that women taking oral contraceptives are at increased risk of dysplasia, epidermoid carcinoma, and adenocarcinoma of the cervix. However, other studies have not found such an association.[Ref]

Endocrine

Endocrine effects have included complex alterations in plasma lipid profiles.[Ref]

All progestins which occur in commercially available oral contraceptive combinations have adverse effects on lipid profiles. These progestins exert antiestrogen and androgen effects and decrease HDL (and HDL2) cholesterol levels and increase LDL cholesterol levels. The estrogen component of oral contraceptive combinations exert opposing effects. Consequently, alterations in lipid profiles are related to the relative amount and potency of the specific estrogen and progestin in a given product. (Levonorgestrel exerts potent progestin, antiestrogen, and androgen effects.)[Ref]

Hepatic

The rate of death due to hepatocellular carcinoma in the United States has not changed during the last 25 years (a time during which use of oral contraceptive hormones has increased dramatically).

A committee of the World Health Organization has reported that in developing countries where hepatitis B virus infection and hepatocellular carcinoma are common, "short term use of oral contraceptives does not appear to be associated with an increased risk. Data on the effects of long term use are scarce."

A recent Italian case control study of women with hepatocellular carcinoma has suggested that the relative risk of hepatocellular carcinoma is 2.2 for oral contraceptive users compared to women who never used oral contraceptives.

A similar American case control study from 1989 also reported a strong association between oral contraceptive use and hepatocellular carcinoma but concluded that: "If this observed association is causal, the actual number of cases of liver cancer in the United States attributable to oral contraceptive use is small. Therefore, these findings do not have public health importance in the United States and other Western nations."[Ref]

Hepatic side effects have included focal nodular hyperplasia, intrahepatic cholestasis, liver cell adenomas, hepatic granulomas, hepatic hemangiomas and well differentiated hepatocellular carcinomas, which have been reported rarely in association with estrogen therapy and therapy with oral contraceptive combinations.[Ref]

Hematologic

Cases of venous thrombosis, pulmonary embolism (sometimes fatal), and arterial thrombosis have been reported rarely.

Previous thrombotic disease is considered a contraindication to use of oral contraceptive combinations.[Ref]

A hematologic concern has been the risk of thromboembolism associated with exogenous estrogens. Because the dose of exogenous estrogens is low in most commercially available preparations, the risk of thromboembolism is minimal for most women. Risk is greater in women who are over age 35, smoke, and/or with a history of previous thrombotic diseases. The incidence of venous thrombosis in women with inherited clotting defects has been greater and developed sooner (within the first six months to one year of therapy).[Ref]

Genitourinary

A common genitourinary side effect has been breakthrough bleeding and spotting, especially during the first several cycles of oral contraceptive use. Nonhormonal causes of such bleeding should be excluded. In addition, oral contraceptive use may cause conception delay.[Ref]

Some women have experienced oligomenorrhea and amenorrhea following termination or oral contraceptive use.[Ref]

Psychiatric

Psychiatric side effects have included depression and precipitation of panic disorder.[Ref]

Immunologic

Immunologic side effects have included rare cases of oral contraceptive induced systemic lupus erythematosus.[Ref]

Nervous system

Nervous system side effects have been rare. A case of chorea has been reported in association with oral contraceptives.[Ref]

Ocular

Ocular side effects have included rare cases of retinal thrombosis. In addition, the manufacturers of oral contraceptive products report that some patients have developed changes in contact lens tolerance.[Ref]

Respiratory

A case of fatal pulmonary venooclusive disease has been reported.[Ref]

Metabolic

Despite the potentially adverse effects of oral contraceptives on lipid levels and glucose tolerance, some investigators have suggested that young diabetic women without existing vascular disease or severe lipidemias may be candidates for low dose oral contraceptive combinations with appropriate clinical monitoring of patient response and tolerance.[Ref]

Metabolic side effects have resulted in altered carbohydrate metabolism. The suggested effect that oral contraceptive combinations may have on glucose tolerance has been varied. Decreased glucose tolerance has been observed, however, studies with low dose preparations have suggested that decreased glucose tolerance due to oral contraceptive combinations generally has been minimal.[Ref]

Some side effects of Lybrel may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.