Ethinyl Estradiol/Norelgestromin (Transdermal)
Uses & Indications
Ethinyl estradiol/norelgestromin transdermal patch is a combination hormonal contraceptive used primarily to prevent pregnancy in women of reproductive age. This patch delivers estrogen (ethinyl estradiol) and a progestin (norelgestromin) through the skin into the bloodstream, providing continuous hormone levels to suppress ovulation.
In addition to contraception, this transdermal system may be prescribed to regulate menstrual cycles, reduce menstrual cramps (dysmenorrhea), and manage symptoms of hormonal imbalance. It is an alternative to oral contraceptives, especially for women who prefer not to take a daily pill.
How It Works
The patch works by releasing ethinyl estradiol and norelgestromin steadily through the skin into the bloodstream. These hormones act together to prevent ovulation — the release of an egg from the ovaries — which is necessary for pregnancy.
Furthermore, the hormones thicken cervical mucus, making it difficult for sperm to enter the uterus, and alter the uterine lining to prevent implantation of a fertilized egg. This multi-pronged hormonal effect effectively reduces the chance of pregnancy.
Because it delivers hormones transdermally, the patch bypasses the gastrointestinal tract and first-pass metabolism in the liver, potentially improving hormone absorption and reducing some gastrointestinal side effects seen with oral contraceptives.
Dosage and Administration
The standard dosing regimen involves applying a new patch once weekly for three consecutive weeks, followed by one patch-free week to allow for withdrawal bleeding similar to a menstrual period.
- Application site: The patch should be applied to clean, dry, intact skin on the buttock, abdomen, upper outer arm, or upper torso (excluding breasts).
- Placement: Avoid areas with cuts, irritation, or excessive hair. Press firmly for 10 seconds to ensure good adhesion.
- Schedule: Change the patch every 7 days on the same day of the week for 3 weeks, then have a patch-free week before starting the next cycle.
- Missed patch: If the patch is off for more than 24 hours, follow the product instructions for backup contraception and patch replacement.
Patients should avoid excessive heat exposure (e.g., hot tubs, saunas) immediately after application, as this may affect patch adhesion.
Side Effects
Common side effects reflect the hormonal nature of the medication and include:
- Skin irritation or rash at the patch site
- Breast tenderness or enlargement
- Nausea and vomiting
- Headaches or migraines
- Mood changes, including depression or irritability
- Breakthrough bleeding or spotting between periods
- Changes in menstrual flow
Serious but rare side effects include blood clots (venous thromboembolism), stroke, heart attack, and high blood pressure. The risk of blood clots is higher in women who smoke, are over 35 years old, or have other risk factors.
Warnings and Precautions
- Smoking: Women over 35 who smoke should not use this patch due to increased cardiovascular risk.
- History of thromboembolic events: Avoid use in women with past or current blood clots, stroke, or heart disease.
- Hypertension: Monitor blood pressure regularly during use.
- Breast cancer: Use with caution or avoid in women with a history of hormone-sensitive cancers.
- Liver disease: Not recommended for severe hepatic impairment.
- Pregnancy and breastfeeding: The patch is contraindicated during pregnancy and generally not recommended during breastfeeding.
- Adherence: Ensure patients understand the importance of timely patch changes to maintain contraceptive efficacy.
Drug Interactions
Certain medications and supplements can decrease the effectiveness of the patch by inducing liver enzymes that metabolize hormones, including:
- Antiepileptics (e.g., phenytoin, carbamazepine)
- Rifampin and other antibiotics
- Herbal supplements such as St. John’s Wort
Conversely, patch hormones can affect the metabolism of other drugs such as cyclosporine and lamotrigine.
Patients should inform healthcare providers about all medications and supplements to assess potential interactions. Use of backup contraception may be advised during interacting drug therapy.
FAQs
Q1: How effective is the Ethinyl Estradiol/Norelgestromin patch?
A: When used correctly, it is over 99% effective in preventing pregnancy. Typical use effectiveness is approximately 91% due to occasional missed patches or errors.
Q2: Can I swim or shower with the patch on?
A: Yes, the patch is waterproof and can be worn during bathing, swimming, and exercise. Just ensure it remains securely attached.
Q3: What if the patch falls off?
A: If it falls off for less than 24 hours, reapply it. If longer than 24 hours, apply a new patch and use backup contraception for 7 days.
Q4: Does the patch protect against sexually transmitted infections (STIs)?
A: No, the patch does not protect against STIs. Barrier methods like condoms are necessary for STI prevention.
Q5: Can I use the patch if I am breastfeeding?
A: It is generally not recommended to use combination hormonal contraceptives while breastfeeding, especially in the first 6 weeks postpartum.
References
- U.S. Food and Drug Administration (FDA) – Ethinyl Estradiol/Norelgestromin Transdermal Patch Drug Information
- Mayo Clinic – Birth Control Patch: How to Use and Side Effects
- MedlinePlus – Contraceptive Patch
