Generic Name

Mestranol and Norethynodrel

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Classification

FDA Approved Indications

• Oral contraception

Mechanism of Action

Mestranol is a prodrug of ethinylestradiol (estrogen), which suppresses ovulation by feedback inhibition of the hypothalamus and pituitary, reducing gonadotropin release. Norethynodrel is a progestin that also suppresses ovulation, alters cervical mucus making it less penetrable to sperm, and changes the endometrial lining to prevent implantation.

Dosage and Administration

Adult: Typically, one tablet daily for 21 or 28 days as directed by the physician.

Pediatric: Not indicated for pediatric use.

Geriatric: Not specifically indicated for geriatric population.

Renal Impairment: Adjustments not well established; use with caution.

Hepatic Impairment: Use is contraindicated or caution advised due to hepatic metabolism.

Pharmacokinetics

Absorption: Well absorbed from gastrointestinal tract.

Distribution: Plasma protein binding varies by component.

Metabolism: Extensively metabolized in the liver via conjugation and hydroxylation.

Excretion: Excreted primarily in urine and feces.

Half Life: Mestranol has a half-life of approximately 2-4 hours, norethynodrel approximately 24 hours.

Contraindications

• History of thromboembolic disorders
• Estrogen-dependent neoplasia
• Abnormal vaginal bleeding of unknown cause
• Pregnancy

Precautions

• History of migraines, smoking, liver disease, hypertension, diabetes, or gallbladder disease.

Adverse Reactions - Common

• Nausea or vomiting (Common)
• Breast tenderness (Common)
• Headache (Common)
• Weight gain (Less common)

Adverse Reactions - Serious

• Deep vein thrombosis (DVT) (Serious/perhaps rare)
• Myocardial infarction (Serious)
• Stroke (Serious)
• Hypertension (Less common)
• Liver tumors (Rare)

Drug-Drug Interactions

• Antibiotics such as penicillins, tetracyclines which may reduce contraceptive effectiveness
• Anticonvulsants like phenytoin, phenobarbital, carbamazepine

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Patient/Family Teaching

• Instruct on proper use, missed dose instructions, and importance of daily intake.
• Warn about side effects, especially signs of thromboembolic events.
• Advise on using additional contraceptive methods if gastrointestinal disturbances occur.

Special Considerations

Black Box Warnings:

• Increased risk of blood clots, stroke, and myocardial infarction, especially in women over 35 who smoke.

Genetic Factors: Genetic variations may influence drug metabolism.

Lab Test Interference: May affect hepatic function tests, coagulation studies, or lipid profiles.

Overdose Management

Signs/Symptoms: Nausea, vomiting, dizziness, or unexpected vaginal bleeding.

Treatment: Supportive care, symptomatic treatment, and gastric lavage if ingestion was recent.

Storage and Handling

Storage: Store at room temperature, away from heat and moisture.

Stability: Stable when stored properly for the duration of labeled shelf life.