Side Effects of Aygestin (norethindrone)

Aygestin (norethindrone) is a man-made form of the female hormone progestin used to treat abnormal uterine bleeding and related conditions (such as amenorrhea and endometriosis).

Progestins are steroid hormones that have the same effect as progesterone. Aygestin works by stopping gonadotropin production from the pituitary gland, leading to prevention of ovulation in females. 

Common side effects of Aygestin include

• fluid retention (edema),
• nausea,
• breast tenderness,
• irregular menstrual cycle,
• breakthrough bleeding,
• spotting,
• weight changes, and
• headache.

Serious side effects of Aygestin include

• deep vein thrombosis and
• depression.

No drug-drug interactions have been conducted and established with Aygestin.

Aygestin is not recommended for pregnant mothers under any circumstances. Aygestin may cause birth defects. Aygestin may enter in breast milk in trace amounts. It should be used with extreme caution in breastfeeding mothers.

Side effects of norethindrone are: 

• edema,
• nausea,
• breast tenderness,
• irregular menstrual cycle,
• breakthrough bleeding,
• spotting,
• weight change, and
• headache.

Deep vein thrombosis and depression may also occur.

The following adverse reactions have been observed in women taking progestins:

• Breakthrough bleeding
• Spotting
• Change in menstrual flow
• Amenorrhea
• Edema
• Changes in weight (decreases, increases)
• Changes in the cervical squamo-columnar junction and cervical secretions
• Cholestatic jaundice
• Rash (allergic) with and without pruritus
• Melasma or chloasma
• Clinical depression
• Acne
• Breast enlargement/tenderness
• Headache/migraine
• Urticaria
• Abnormalities of liver tests (i.e., AST, ALT, Bilirubin)
• Decreased HDL cholesterol and increased LDL/HDL ratio
• Mood swings
• Nausea
• Insomnia
• Anaphylactic/anaphylactoid reactions
• Thrombotic and thromboembolic events (e.g., deep vein thrombosis, pulmonary embolism, retinal vascular thrombosis, cerebral thrombosis and embolism)
• Optic neuritis (which may lead to partial or complete loss of vision)

Drug/Laboratory Tests Interactions

The following laboratory test results may be altered by the use of estrogen/progestin combination drugs:

1. Accelerated prothrombin time, partial thromboplastin time, and platelet aggregation time; increased platelet count; increased factors II, VII antigen, VIII antigen, VIII coagulant activity, IX, X, XII, VII-X complex, II-VII-X complex, and beta-thromboglobulin; decreased levels of antifactor Xa and antithrombin III, decreased antithrombin III activity; increased levels of fibrinogen and fibrinogen activity; increased plasminogen antigen and activity.
2. Increased thyroid-binding globulin (TBG) levels leading to increased circulating total thyroid hormone levels as measured by protein-bound iodine (PBI), T4 levels (by column or by radioimmunoassay) or T3 levels by radioimmunoassay. T3 resin uptake is decreased, reflecting the elevated TBG. Free T4 and free T3 concentrations are unaltered. Patients on thyroid replacement therapy may require higher doses of thyroid hormone.
3. Other binding proteins may be elevated in serum (i.e., corticosteroid binding globulin (CBG), sex hormone binding globulin (SHBG)) leading to increased circulating corticosteroid and sex steroids, respectively. Free or biologically active hormone concentrations are unchanged. Other plasma proteins may be increased (angiotensinogen/renin substrate, alpha-1-antitrypsin, ceruloplasmin).
4. Increased plasma HDL and HDL2 cholesterol subfraction concentrations, reduced LDL cholesterol concentration, increased triglycerides levels.
5. Impaired glucose metabolism.
6. Reduced response to metyrapone test.