Drug Guide
Ethinyl Estradiol; Norethindrone Acetate
Classification
Therapeutic: Contraceptive and hormone replacement therapy
Pharmacological: Estrogen and progestin combination
FDA Approved Indications
- Contraception
- Treatment of acne vulgaris in females 15 years and older and weighing at least 90 kg (198 pounds)
- Premenstrual dysphoric disorder (PMDD)
- Suppression of ovarian function for hormonal indications
Mechanism of Action
The combination of ethinyl estradiol (estrogen) and norethindrone acetate (progestin) prevents ovulation by suppressing the secretion of gonadotropins. It causes changes in the cervical mucus and endometrial lining, making implantation and sperm penetration difficult.
Dosage and Administration
Adult: Administer as directed, typically one tablet daily for 21 or 24 days followed by placebo or no pills, depending on the formulation.
Pediatric: Not indicated for pediatric use.
Geriatric: Not indicated for use in the elderly.
Renal Impairment: Use with caution, doses may need adjustment depending on response.
Hepatic Impairment: Contraindicated in women with hepatic disease or tumors.
Pharmacokinetics
Absorption: Well absorbed from the gastrointestinal tract.
Distribution: Bound extensively to plasma proteins, mainly albumin and sex hormone-binding globulin.
Metabolism: Metabolized in the liver via conjugation and oxidation pathways.
Excretion: Excreted primarily in the urine and feces after hepatic metabolism.
Half Life: Ethinyl estradiol: approximately 17 hours; Norethindrone: approximately 8 hours.
Contraindications
- History of thrombotic disorders
- Active or history of breast cancer
- Hepatic disease or tumor
- Elevated serum liver enzymes without diagnosis
- Pregnancy
Precautions
- Smoking, especially in women over 35
- History of hypertension, diabetes, or lipid disorders
- Use with caution in women with migraines or cardiovascular risk factors
Adverse Reactions - Common
- Nausea (Common)
- Breast tenderness (Common)
- Headache (Common)
- Nervousness (Common)
Adverse Reactions - Serious
- Venous thromboembolism (Less common)
- Myocardial infarction (Less common)
- Stroke (Less common)
- Liver tumors (Rare)
- Hypertension (Less common)
Drug-Drug Interactions
- Certain antibiotics (e.g., rifampin), anticonvulsants (e.g., phenytoin), and antiretrovirals may decrease effectiveness.
Drug-Food Interactions
- Products containing St. John’s Wort may reduce contraceptive effectiveness.
Drug-Herb Interactions
N/ANursing Implications
Assessment: Monitor blood pressure, weight, and for signs of thrombotic events.
Diagnoses:
- Risk for thrombosis
- Ineffective tissue perfusion
Implementation: Educate patient on adherence, risks, and recognition of adverse effects.
Evaluation: Assess for effectiveness of contraception and adverse reactions.
Patient/Family Teaching
- Take pills at the same time daily.
- Use additional contraception if prescribed, especially if more than one pill is missed.
- Report signs of thrombotic events, abnormal bleeding, or severe headache.
- Avoid smoking and discuss risks with healthcare provider.
Special Considerations
Black Box Warnings:
- Women who smoke and are over 35 years old are at increased risk of serious cardiovascular events.
Genetic Factors: Increased risk with genetic clotting disorders such as Factor V Leiden.
Lab Test Interference: May affect serum levels of certain tests, including thyroid function and coagulation tests.
Overdose Management
Signs/Symptoms: Nausea, vomiting, dizziness, and withdrawal bleeding may occur.
Treatment: Supportive care; remove remaining pills; symptomatic treatment.
Storage and Handling
Storage: Store at room temperature away from moisture and heat.
Stability: Stable for the duration of shelf life as indicated by the manufacturer.