Aygestin (norethindrone) is a prescription progestin medication used to treat a variety of gynecological and hormonal conditions. As a semi-synthetic form of the natural hormone progesterone, it provides a targeted therapeutic effect, primarily on the uterine lining (endometrium). It is a well-established option in hormonal management, offering clinicians a versatile tool for addressing abnormal uterine bleeding, amenorrhea, and endometriosis, as well as serving as a component of hormone replacement therapy. Its mechanism of action and dosing flexibility make it a cornerstone in personalized treatment plans.

Features

• Active Ingredient: Norethindrone (a semi-synthetic progestin)
• Standard Dosage Forms: 5 mg oral tablets
• High Bioavailability: Effective oral administration
• Targeted Action: Primarily acts on endometrial tissue
• Chemical Classification: 19-nortestosterone derivative
• Prescription Status: Available only with a healthcare provider’s authorization

Benefits

• Effectively manages and reduces abnormal uterine bleeding by stabilizing the endometrium.
• Provides relief from the pain associated with endometriosis by inducing endometrial atrophy.
• Restores regular menstrual cycles in women with secondary amenorrhea.
• Offers a progestin-only option for women who cannot or prefer not to use estrogen-containing therapies.
• Allows for flexible dosing schedules tailored to individual patient needs and specific conditions.
• Serves as a protective agent against endometrial hyperplasia in women receiving estrogen replacement therapy.

Common use

Aygestin is prescribed for several specific medical indications. Its primary use is in the treatment of abnormal uterine bleeding (dysfunctional uterine bleeding) where no underlying pathological cause, such as fibroids or cancer, has been identified. It works by transforming the proliferative endometrium into a secretory state, promoting organized shedding and thus controlling heavy or irregular bleeding. It is also a second-line therapy for the management of endometriosis, helping to alleviate pain by causing decidualization and eventual atrophy of ectopic endometrial tissue. Furthermore, Aygestin is used to treat secondary amenorrhea (the absence of menstrual periods in women who have previously menstruated) by triggering withdrawal bleeding. In postmenopausal women undergoing estrogen replacement therapy (ERT), it is added cyclically or continuously to provide endometrial protection and prevent hyperplasia.

Dosage and direction

Dosage is highly individualized and must be strictly determined by a healthcare provider based on the specific condition being treated. Tablets should be taken orally, with or without food, but consistency in timing is recommended to maintain stable hormone levels.

• Abnormal Uterine Bleeding: 5 to 10 mg daily for 5 to 10 days during the second half of the planned menstrual cycle. A withdrawal bleed typically occurs within 3 to 7 days after discontinuing the medication.
• Endometriosis: 5 mg daily for 14 days. This may be increased by 2.5 mg per day every two weeks up to a maximum of 15 mg daily. Therapy usually continues for 6 to 9 months or until breakthrough bleeding mandates a temporary discontinuation.
• Amenorrhea: 2.5 to 10 mg daily for 5 to 10 days, usually given during the last half of the theoretical cycle.
• Endometrial Protection with ERT: Typically 2.5 mg to 10 mg daily, administered either cyclically (e.g., for 10-14 days per month) or continuously, depending on the estrogen regimen and patient profile.

The patient should follow the prescribed schedule precisely and not adjust the dose without consulting their physician.

Precautions

Before initiating therapy with Aygestin, a thorough patient evaluation is necessary. A complete medical history should be taken, with particular attention to personal or family history of thromboembolic disorders, breast or genital cancers, liver dysfunction, depression, asthma, epilepsy, migraine, diabetes, or cardiac or renal disease. A physical exam should include blood pressure measurement and breast and pelvic examinations, including a Pap smear, to rule out malignant conditions. Use with caution in patients with conditions that may be aggravated by fluid retention, such as epilepsy, migraine, asthma, or cardiac or renal dysfunction. Patients with a history of depression should be monitored closely, as progestins may exacerbate this condition. Aygestin may cause some degree of fluid retention; therefore, it should be used cautiously in patients with pre-existing conditions that might be influenced by this factor (e.g., hypertension, heart failure, renal disease). Diabetic patients should be monitored closely, as progestins can decrease glucose tolerance.

Contraindications

Aygestin is contraindicated in patients with known hypersensitivity to norethindrone or any component of the formulation. Its use is also contraindicated in the presence of any of the following conditions:

• Known or suspected pregnancy
• Undiagnosed abnormal genital bleeding
• Known or suspected carcinoma of the breast
• Active or past history of thromboembolic disorders (e.g., deep vein thrombosis, pulmonary embolism)
• Severe liver disease or liver tumors (benign or malignant)
• As a diagnostic test for pregnancy

Possible side effect

As with all hormonal therapies, Aygestin can cause side effects, which vary in frequency and severity among individuals. Not all patients will experience these effects.

• Very Common (>10%): Breakthrough bleeding, spotting, changes in menstrual flow, amenorrhea, breast tenderness.
• Common (1-10%): Nausea, headache, dizziness, fluid retention and edema, weight changes, acne, mood swings, fatigue, insomnia, hirsutism, alopecia.
• Uncommon (<1%): Melasma (chloasma), rash, pruritus, changes in libido, depression, glucose intolerance, hypertension.
• Rare but Serious: Thromboembolic events (e.g., deep vein thrombosis, pulmonary embolism, stroke, myocardial infarction), hepatic adenomas, jaundice.

Patients should be advised to report any severe headaches, visual disturbances, sharp chest pain, coughing up blood, severe leg pain, or significant mood changes to their healthcare provider immediately.

Drug interaction

Aygestin (norethindrone) may interact with other medications, potentially altering its effectiveness or the effects of the other drugs. Key interactions include:

• Enzyme Inducers: Drugs such as rifampin, rifabutin, barbiturates (e.g., phenobarbital), carbamazepine, phenytoin, primidone, topiramate, and St. John’s Wort can significantly increase the metabolism of norethindrone, reducing its plasma concentrations and clinical efficacy. Dose adjustments of Aygestin may be required.
• Anticoagulants: Progestins may alter the activity of anticoagulants like warfarin; close monitoring of prothrombin time (INR) is advised.
• Antidiabetic Drugs: Insulin or oral hypoglycemic agents may need dosage adjustments as progestins can decrease glucose tolerance.
• Cyclosporine: Norethindrone may inhibit the metabolism of cyclosporine, potentially increasing its plasma levels and risk of toxicity.
• Thyroid Hormone: Norethindrone may increase thyroxine-binding globulin (TBG) levels, leading to increased total thyroid hormone levels. Free thyroid hormone levels typically remain unchanged.

Patients must provide their doctor with a complete list of all medications, including over-the-counter drugs and herbal supplements.

Missed dose

If a dose is missed, it should be taken as soon as remembered on the same day. If a full day has been missed, the patient should take the missed dose as soon as possible and then resume the regular schedule the next day. They should not double the dose to make up for the missed one. In the case of breakthrough bleeding, a missed dose can sometimes be a trigger; consistent dosing is key to maintaining endometrial stability. If multiple doses are missed or instructions are unclear, the patient should contact their healthcare provider or pharmacist for guidance.

Overdose

There have been no reports of serious ill effects from acute overdose of norethindrone. Serious overdose may cause nausea and vomiting, and withdrawal bleeding may occur. Since the drug is hormonally active, the effects could be prolonged. There is no specific antidote. Treatment should be symptomatic and supportive. Gastric lavage may be considered if ingestion was very recent. Medical attention should be sought.

Storage

Store Aygestin tablets at controlled room temperature, 20°C to 25°C (68°F to 77°F), with excursions permitted between 15°C and 30°C (59°F and 86°F). Keep the container tightly closed and protect from light and moisture. Keep all medications out of the reach of children and pets. Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed.

Disclaimer

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or medication. Never disregard professional medical advice or delay in seeking it because of something you have read here. The content has been compiled from various resources but may not be exhaustive or fully updated. The manufacturer’s official prescribing information should be consulted for complete details.

Reviews

• Dr. Eleanor Vance, OB/GYN: “Aygestin remains a reliable workhorse in my practice for managing abnormal uterine bleeding. Its predictable effect on the endometrium allows for excellent control, and the 5mg tablet offers convenient dosing. It’s a foundational agent for many of my treatment plans.”
• Clinical Pharmacist Review: “From a pharmacological standpoint, norethindrone’s well-understood profile and metabolism make it a predictable choice. Its interactions with hepatic enzyme inducers are a crucial counseling point for providers and patients to ensure therapeutic efficacy isn’t compromised.”
• Patient Experience (Endometriosis): “After struggling with the pain of endometriosis for years, my doctor prescribed Aygestin. The first few weeks involved some adjustment with spotting, but after that, my pain levels decreased significantly. It gave me a quality of life I hadn’t had in a long time.”
• Patient Experience (HRT): “I take Aygestin alongside my estrogen for endometrial protection. The cyclic schedule was easy to get used to. I experienced some initial bloating, but that subsided. I feel confident that I’m on a balanced and protective regimen.”