Contraceptives, Oral (Progestin-Only Products)

Pronunciation: proe-JES-tin
Class: Hormone, Contraceptive

Trade Names

Camila
- Tablets norethindrone 0.35 mg

Errin
- Tablets norethindrone 0.35 mg

Heather
- Tablets norethindrone 0.35 mg

Jolivette
- Tablets norethindrone 0.35 mg

Micronor
- Tablets norethindrone 0.35 mg

Nor-QD
- Tablets norethindrone 0.35 mg

Nora-BE
- Tablets norethindrone 0.35 mg

Pharmacology

Thickens cervical mucus, interferes with implantation, lowers the midcycle luteinizing hormone and follicle-stimulating hormone peaks, alters endometrium, and may suppress ovulation.

Pharmacokinetics

Absorption

Completely and rapidly absorbed. T _max is approximately 1.2 h. C _max and AUC are approximately 4,817 pg/mL and 21,233 pg•h/mL, respectively. Absolute bioavailability is approximately 65%.

Distribution

Vd is 4 L/kg; 36% is bound to sex hormone–binding globulin (SHBG) and 61% to albumin.

Metabolism

Undergoes reduction, followed by sulfate and glucuronide conjugation. The majority of metabolites in circulation are sulfate, with the majority of urinary metabolites being glucuronides.

Elimination

The t _½ is approximately 7.7 h. Less than 5% is excreted unchanged, while more than 50% and 20% to 40% is excreted as metabolites in urine and feces, respectively. Plasma Cl is approximately 600 L/day. Serum levels are near baseline within 24 h.

Indications and Usage

Prevention of pregnancy.

Contraindications

Active liver disease; benign or malignant liver tumors; hypersensitivity to any component of the product; known or suspected breast carcinoma; undiagnosed abnormal genital bleeding; known or suspected pregnancy.

Dosage and Administration

PO 1 tablet daily. Administration is continuous with no interruption between pill packs.

General Advice

If GI upset occurs, administer with food.

Storage/Stability

Store at 59° to 77°F.

Drug Interactions

Contraceptive effectiveness may be reduced when coadministered with antibiotics and/or anticonvulsants.

Norethindrone plasma levels may be reduced, decreasing efficacy.

Significant changes (increase and decrease) in the plasma levels of progestins have been noted.

Reduced plasma levels and pharmacologic effects of norethindrone.

May reduce the effectiveness of contraceptive steroids.

Laboratory Test Interactions

SHBG concentrations may be decreased; thyroxine concentrations may be reduced.

Adverse Reactions

CNS

Dizziness; headache.

Dermatologic

Androgenic adverse reactions (including acne and hirsutism).

GI

Nausea.

Genitourinary

Breast tenderness, frequent and irregular bleeding, long duration of bleeding episodes and amenorrhea, menstrual irregularities.

Precautions

Pregnancy

Category X .

Lactation

Excreted in breast milk.

Children

Use not indicated before menarche.

Carcinoma

Increased risk of developing breast cancer has been reported with use of combined oral contraceptives.

Diabetes

Slight deterioration in glucose tolerance with increases in plasma insulin may occur.

Delayed follicular atresia/ovarian cysts

If follicular development occurs, atresia of the follicle may be delayed, and the follicle may continue to grow beyond the size it would attain in a normal cycle.

Ectopic pregnancy

Ectopic pregnancy has been reported with progestin-only oral contraceptives.

GI

Diarrhea and/or vomiting may reduce hormone absorption resulting in decreased serum concentrations.

Hepatic neoplasm

Increased risk of developing benign hepatic adenomas has been reported with use of combined oral contraceptives.

Irregular genital bleeding

Irregular menstrual patterns are common.

Lipid metabolism

HDL, HDL ² , and apolipoprotein A-I and A-II may be decreased, while hepatic lipase may be increased.

Smoking

Greatly increases the possibility of heart attacks or strokes; women who use oral contraceptives are strongly advised not to smoke.

Overdosage

Symptoms

No reports of serious effects.

Patient Information

• Advise patient to use additional method of birth control until after first wk of administration in initial cycle.
• Encourage patients who smoke to stop. CV dysfunction and thromboembolic disease have been associated with use of oral contraceptives in patients who smoke.
• Advise patient to wait at least 3 mo after discontinuing oral contraceptives before trying to become pregnant.
• Instruct patient to report symptoms of blood clots (eg, pain, numbness, shortness of breath, visual disturbances), prolonged bleeding, amenorrhea, or severe abdominal pain.
• Advise patients that progestin-only contraceptives do not protect against transmission of HIV (AIDS) and other STDs (eg, chlamydia, genital herpes).
• Advise patients that it is good medical practice for sexually active women using oral contraceptives to have annual history and physical examination.
• Advise patient that a headache or a worsening migraine with a new pattern that is recurrent, persistent, or severe requires discontinuation of oral contraceptives and evaluation of the cause.
• Instruct patient to take product at the same time each day, including throughout all bleeding episodes.
• Missed dose(s): Norethindrone: If more than 3 h late or 1 or more doses is missed, take missed dose as soon as remembered, then take the next dose at the regular time, and use a backup method of contraception (eg, condom and/or spermicide) each time there is sexual intercourse for the next 48 h.

Copyright © 2009 Wolters Kluwer Health.