Professional Information — Nora-Be 28 Day

Indications and Usage

1. Indications. Progestin-only oral contraceptives are indicated for the prevention of pregnancy.

2. Efficacy. If used perfectly, the first-year failure rate for progestin-only oral contraceptives is 0.5%. However, the typical failure rate is estimated to be closer to 5%, due to late or omitted pills. The following table lists the pregnancy rates for users of all major methods of contraception.

Emergency Contraceptive Pills: Treatment initiated within 72 hours after unprotected intercourse reduces the risk of pregnancy by at least 75%.⁹

Lactational Amenorrhea Method: LAM is a highly effective, temporary method of contraception.¹⁰

Source: Trussell, J, Contraceptive Efficacy. In: Hatcher RA, Trussell J, Stewart F, Cates W, Stewart GK, Kowal D, Guest F, Contraceptive Technology: Seventeenth Revised Edition. New York NY: Irvington Publishers, 1998.

1. Among typical couples who initiate use of a method (not necessarily for the first time), the percentage who experience an accidental pregnancy during the first year if they do not stop use for any reason.

2. Among couples who initiate use of a method (not necessarily for the first time), and who use it perfectly (both consistently and correctly), the percentage who experience an accidental pregnancy during the first year if they do not stop use for any other reason.

3. Among couples attempting to avoid pregnancy, the percentage who continue to use a method for one year.
4. The percentage of women becoming pregnant noted in columns (2) and (3) are based on data from populations where contraception is not used and from women who cease using contraception in order to become pregnant. Among such populations, about 89% become pregnant within one year. This estimate was lowered slightly (to 85%) to represent the percentage that would become pregnant within one year among women now relying on reversible methods of contraception if they abandoned contraception altogether.
5. Foams, creams, gels, vaginal suppositories, and vaginal film.
6. Cervical mucus (ovulation) method supplemented by calendar in the pre-ovulatory and basal body temperature in the post-ovulatory phases.
7. With spermicidal cream or jelly.
8. Without spermicides.

9. The treatment schedule is one dose within 72 hours after unprotected intercourse, and a second dose 12 hours after the first dose. The Food and Drug Administration has declared the following brands of oral contraceptives to be safe and effective for emergency contraception: Ovral^® (1 dose is 2 white pills), Alesse^® (1 dose is 5 pink pills), Nordette^® or Levlen^® (1 dose is 4 yellow pills).

10. However, to maintain effective protection against pregnancy, another method of contraception must be used as soon as menstruation resumes, the frequency or duration of breastfeeds is reduced, bottle feeds are introduced, or the baby reaches 6 months of age.

Dosage and Administration

To achieve maximum contraceptive effectiveness, Nora-BE must be taken exactly as directed. One tablet is taken every day, at the same time. Administration is continuous, with no interruption between pill packs. See PATIENT LABELING for detailed instructions.

Contraindications

Progestin-only oral contraceptives (POPs) should not be used by women who currently have the following conditions:

• Known or suspected pregnancy
• Known or suspected carcinoma of the breast
• Undiagnosed abnormal genital bleeding
• Hypersensitivity to any component of this product
• Benign or malignant liver tumors
• Acute liver disease

Adverse Reactions

• Menstrual irregularity is the most frequently reported side effect.
• Frequent and irregular bleeding are common, while long duration of bleeding episodes and amenorrhea are less likely.
• Headache, breast tenderness, nausea, and dizziness are increased among progestin-only oral contraceptive users in some studies.
• Androgenic side effects such as acne, hirsutism, and weight gain occur rarely.

Drug Interactions

Change in contraceptive effectiveness associated with co-administration of other products:

a. Anti-infective agents and anticonvulsants. Contraceptive effectiveness may be reduced when hormonal contraceptives are co-administered with antibiotics, anticonvulsants, and other drugs that increase the metabolism of contraceptive steroids. This could result in unintended pregnancy or breakthrough bleeding. Examples include rifampin, barbiturates, phenylbutazone, phenytoin, carbamazepine, felbamate, oxcarbazepine, topiramate, and griseofulvin.

b. Anti-HIV protease inhibitors. Several of the anti-HIV protease inhibitors have been studied with co-administration of oral contraceptives; significant changes (increase and decrease) in the plasma levels of the estrogen and progestin have been noted in some cases. The safety and efficacy of OC products may be affected with the co-administration of anti-HIV protease inhibitors. Health care providers should refer to the label of the individual anti-HIV protease inhibitors for further drug-drug interaction information.

c. Herbal products. Herbal products containing St. John's Wort (hypericum perforatum) may induce hepatic enzymes (cytochrome P450) and p-glycoprotein transporter and may reduce the effectiveness of contraceptive steroids. This may also result in breakthrough bleeding.

Overdosage

There have been no reports of serious ill effects from overdosage, including ingestion by children.

Description

Each white Nora-BE^® tablet provides a continuous oral contraceptive regimen of 0.35 mg norethindrone daily, and the inactive ingredients include lactose, magnesium stearate, povidone, and starch.

The chemical name for norethindrone is 17-Hydroxy-19-Nor-17α-pregn-4-en-20-yn-3-one. The structural formula follows:

norethindrone

Therapeutic class = oral contraceptive.

Clinical Pharmacology

1. Mode of Action. Nora-BE progestin-only oral contraceptives prevent conception by suppressing ovulation in approximately half of users, thickening the cervical mucus to inhibit sperm penetration, lowering the mid-cycle LH and FSH peaks, slowing the movement of the ovum through the fallopian tubes, and altering the endometrium.

2. Pharmacokinetics.
Absorption: Norethindrone is rapidly absorbed with maximum plasma concentrations occurring within 1 to 2 hours after Nora-BE administration (see Table 1). Norethindrone appears to be completely absorbed following oral administration; however, it is subject to first pass metabolism resulting in an absolute bioavailability of approximately 65%.

Figure 1:         Mean ± SD Norethindrone Plasma Concentrations Following Nora-BE Administration.

Peak plasma concentrations occur approximately 1 hour after administration (mean T_max 1.2 hours). The mean (SD) C_max was 4816.8 (1532.6) pg/mL and generally occurred within 1 hour (mean) of tablet administration, ranging from 0.5 to 2 hours. The mean (SD) C_avg was 885 (250) pg/mL, however, the mean concentration at 24 hrs was 130 (47) pg/mL.

Table 1 provides summary statistics of the pharmacokinetic parameters associated with single dose Nora-BE administration.

Table 1:          Mean ± SD Pharmacokinetic Parameters Following Single Dose Administration of Nora-BE in 12 Healthy Female Subjects Under Fasting Conditions

The food effect on the rate and extent of norethindrone absorption after Nora-BE administration has not been evaluated.

Distribution: Following oral administration, norethindrone is 36% bound to sex hormone-binding globulin (SHBG) and 61% bound to albumin. Volume of distribution of norethindrone is approximately 4 L/kg.

Metabolism: Norethindrone undergoes extensive biotransformation, primarily via reduction, followed by sulfate and glucuronide conjugation; less than 5% of a norethindrone dose is excreted unchanged; greater than 50% and 20-40% of a dose is excreted in urine and feces, respectively. The majority of metabolites in the circulation are sulfate, with glucuronides accounting for most of the urinary metabolites.

Excretion: Plasma clearance rate for norethindrone has been estimated to be approximately 600 L/day. Norethindrone is excreted in both urine and feces, primarily as metabolites. The mean terminal elimination half-life of norethindrone following single dose administration of Nora-BE is approximately 8 hours.

How Supplied / Storage and Handling

Nora-BE^® (norethindrone tablets USP 0.35 mg) are packaged in cartons of six blister cards (NDC 0480-3475-16) each containing 28 tablets. Each white, round, flat-faced bevel edge tablet is debossed with TV on one side and N62 on the other side.

Patient Counseling Information

1. See  PATIENT LABELING  for detailed information.

2. Counseling issues. The following points should be discussed with prospective users before prescribing progestin-only oral contraceptives:

• The necessity of taking pills at the same time every day, including throughout all bleeding episodes.
• The need to use a backup method such as condoms and spermicides for the next 48 hours whenever a progestin-only oral contraceptive is taken 3 or more hours late.
• The potential side effects of progestin-only oral contraceptives, particularly menstrual irregularities.
• The need to inform the clinician of prolonged episodes of bleeding, amenorrhea or severe abdominal pain.
• The importance of using a barrier method in addition to progestin-only oral contraceptives if a woman is at risk of contracting or transmitting STDs/HIV.