Aygestin 5 mg Tablets

Brand Name

The medication is marketed under the brand name Aygestin, a widely acknowledged label in the realm of hormonal treatments for gynecological conditions.

International Nonproprietary Name (INN)

The active ingredient in this product is identified globally as norethindrone, a name standardized for consistency across international pharmacological frameworks.

Form of Release

Aygestin is available as oral tablets, designed for convenient administration. Each tablet contains 5 mg of the active substance and is typically packaged in blister packs or bottles, depending on regional distribution preferences.

Composition

Each tablet of Aygestin includes 5 mg of norethindrone as its primary active component. The formulation incorporates several inactive ingredients, such as lactose monohydrate, which acts as a filler, and microcrystalline cellulose, providing structural support. Additional excipients like magnesium stearate serve as lubricants to facilitate manufacturing, while cornstarch aids in tablet disintegration. Small amounts of other stabilizers may be present to ensure the drug maintains its quality and potency throughout its shelf life, offering a reliable product for patients.

Pharmacologic Properties

Pharmacodynamics

Aygestin functions as a progestin, mimicking the effects of natural progesterone in the body. It exerts its therapeutic action by binding to progesterone receptors in target tissues, such as the uterus and pituitary gland, where it modulates hormonal activity. This binding suppresses gonadotropin-releasing hormone (GnRH) secretion, reducing luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels, which in turn inhibits ovulation in some contexts. In the endometrium, it induces a secretory transformation, stabilizing the uterine lining and reducing excessive proliferation, a key mechanism in treating conditions like abnormal uterine bleeding.

The progestational effects also thicken cervical mucus, impeding sperm movement, and alter tubal motility, further contributing to its contraceptive potential when used in specific regimens. Beyond reproductive tissues, it exerts mild androgenic activity due to its structural similarity to testosterone, though this is less pronounced than with other progestins. Clinical evidence highlights its ability to regulate menstrual cycles, decrease bleeding volume, and alleviate associated pain, making it a valuable tool in gynecological care. Its focused action on progesterone pathways ensures targeted outcomes with a distinct hormonal profile.

Pharmacokinetics

Following oral administration, Aygestin is absorbed efficiently from the gastrointestinal tract, reaching peak plasma concentrations within 1 to 2 hours. Food intake does not significantly alter its bioavailability, allowing flexibility in dosing schedules. The drug binds extensively to plasma proteins, primarily sex hormone-binding globulin (SHBG) and albumin, at approximately 97%, directing its distribution to reproductive tissues and the liver.

Metabolism occurs predominantly in the liver via cytochrome P450 enzymes, notably CYP3A4, converting norethindrone into several metabolites, some of which retain minor progestational activity. The half-life ranges from 5 to 14 hours, depending on individual metabolism, supporting once- or twice-daily dosing. Elimination is primarily urinary, with about 50–60% of the dose excreted as metabolites in urine, and the remainder via feces through biliary excretion. This balanced clearance profile ensures the drug’s effects dissipate within days of discontinuation, minimizing prolonged systemic exposure.

Indications for Use

Aygestin is prescribed primarily for the management of abnormal uterine bleeding due to hormonal imbalances in women without underlying organic pathology. It is effective in restoring regular menstrual patterns by stabilizing the endometrium and reducing excessive blood loss. The medication is also indicated for the treatment of endometriosis, where it suppresses endometrial growth outside the uterus, alleviating pain and inflammation associated with this condition.

Another key use is in secondary amenorrhea, where it induces withdrawal bleeding to mimic a natural cycle, often following estrogen priming. In some cases, healthcare providers may employ it for contraception, though this is typically off-label and less common than dedicated contraceptive formulations. Its versatility extends to managing symptoms of premenstrual syndrome (PMS) or dysmenorrhea when tied to progesterone deficiency, offering relief to women with these gynecological challenges.

Contraindications

Aygestin is contraindicated in women with a history of thromboembolism, including deep vein thrombosis or pulmonary embolism, due to the progestin-related risk of clotting. It is also prohibited in those with known or suspected breast cancer or other progesterone-sensitive malignancies, as it could potentially stimulate tumor growth. Severe liver dysfunction, such as cirrhosis or hepatic tumors, precludes its use, given its extensive hepatic metabolism.

Pregnancy is an absolute contraindication, as the drug may harm fetal development or increase miscarriage risk if taken inadvertently. Patients with undiagnosed vaginal bleeding should avoid it until the cause is determined, as it could mask serious conditions like endometrial cancer. Hypersensitivity to norethindrone or any tablet component, such as lactose, is another strict limitation, with potential reactions ranging from mild rashes to severe allergic responses.

Method of Administration and Dosage

Administration Guidelines

The tablets should be taken orally, swallowed whole with water to ensure proper absorption. They can be consumed with or without meals, providing ease of integration into daily routines. Consistency in timing each day enhances efficacy, particularly for conditions requiring steady hormonal levels, and crushing or splitting the tablets is not recommended unless advised by a healthcare provider.

Dosage for Adults and Children

For adult women, the dosage of Aygestin varies by indication. For abnormal uterine bleeding or endometriosis, the typical regimen is 5 mg to 10 mg daily (1–2 tablets) for 5 to 10 days per cycle, often starting on day 5 of the menstrual cycle. For secondary amenorrhea, 2.5 mg to 10 mg daily for 5 to 10 days is common, adjusted based on response. Adolescents post-menarche may follow similar dosing under medical supervision, but pre-pubertal children are not candidates, as the drug targets reproductive hormonal systems.

Dose Adjustment in Specific Conditions

No specific adjustments are required for renal impairment, as kidney function plays a secondary role in clearance. In mild to moderate liver dysfunction, caution is advised due to metabolic reliance on the liver, with severe hepatic impairment contraindicating use entirely. Missed doses should be taken as soon as remembered unless nearing the next dose, avoiding double dosing. Individual health conditions may prompt tailored regimens, guided by regular monitoring and physician oversight.

Side Effects

Aygestin may trigger a variety of side effects, though many women experience only mild or temporary reactions. Common issues include bloating, weight gain, or breast tenderness, reflecting its progestational effects on fluid retention and tissue sensitivity. Menstrual irregularities, such as spotting or breakthrough bleeding, often occur early in treatment but typically stabilize with continued use.

Headaches, mood swings, or fatigue are reported less frequently, tied to hormonal fluctuations. Serious but rare effects include thromboembolism (e.g., leg swelling or chest pain), liver dysfunction (e.g., jaundice), or severe allergic reactions (e.g., rash or difficulty breathing), necessitating immediate discontinuation and medical evaluation. Acne or hair growth may emerge due to mild androgenic activity, though these are uncommon. Regular check-ups help manage these effects and ensure the therapy remains appropriate.

Overdose

Symptoms of Overdose

Excessive intake of Aygestin is unlikely to cause acute, severe symptoms due to its moderate potency and rapid metabolism. Overdose may manifest as intensified side effects, such as nausea, vomiting, or heavy vaginal bleeding, reflecting an exaggerated hormonal response. Specific overdose profiles are not well-documented, but prolonged excess could heighten risks like headache or fatigue.

First Aid Measures

In the event of overdose, medical consultation is recommended, though urgent intervention is rarely necessary. No specific antidote exists, so care focuses on symptom relief, such as rest for fatigue or antiemetics for nausea. Monitoring is advised until symptoms subside, typically within hours to days, given the drug’s pharmacokinetic clearance.

Drug Interactions

Effects on Other Medications

Aygestin can be influenced by drugs that affect cytochrome P450 enzymes, particularly CYP3A4 inducers like rifampin or phenytoin, which may accelerate metabolism and reduce efficacy. This interaction may require alternative treatments or increased monitoring. Inhibitors such as ketoconazole could elevate norethindrone levels, though this is rarely clinically significant.

The medication may slightly alter the metabolism of drugs like warfarin, potentially enhancing anticoagulant effects and necessitating clotting checks. Co-use with other hormonal agents, such as contraceptives, requires careful coordination to avoid additive effects. Patients should provide a complete medication list to their healthcare provider to assess potential interactions fully.

Compatibility with Alcohol and Food

Moderate alcohol use does not impair the drug’s effectiveness, allowing typical consumption without concern. Food intake has negligible impact on absorption, so tablets can be taken with meals or on an empty stomach, accommodating patient preferences seamlessly.

Special Precautions

Use During Pregnancy and Breastfeeding

Aygestin is contraindicated in pregnancy, as progestins may disrupt fetal development or increase miscarriage risk if taken inadvertently. Women should confirm non-pregnant status before starting and discontinue immediately if pregnancy occurs. During breastfeeding, it is generally avoided in the early postpartum period, as norethindrone passes into milk and could affect infant growth, though low doses may be considered later with medical guidance.

Non-hormonal alternatives are preferred during lactation to minimize infant exposure, with a switch to Aygestin only if benefits outweigh risks after breastfeeding stabilizes.

Impact on Driving and Operating Machinery

The medication does not typically affect cognitive or motor abilities, making it safe for most women to drive or operate machinery. Rare reports of dizziness or fatigue suggest caution during initial use until personal tolerance is confirmed, especially in the first few days.

Considerations for Elderly and Pediatric Populations

Elderly women rarely use Aygestin, as its indications target reproductive-age concerns, and postmenopausal use is limited to specific off-label scenarios with heightened risk awareness. Adolescents post-menarche can use it safely under supervision, with no notable differences from adults, while pre-pubertal children are excluded due to lack of hormonal relevance and untested safety in this group.