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Genora 1/50 Side Effects

Generic name: mestranol / norethindrone

Medically reviewed by Last updated on Nov 20, 2022.

Note: This document contains side effect information about mestranol / norethindrone. Some dosage forms listed on this page may not apply to the brand name Genora 1/50.

Applies to mestranol / norethindrone: oral tablet.


  • Smoking cigarettes while using this drug raises the chance of very bad heart and blood-related side effects. This chance is raised with age (mainly in women older than 35 years of age). It is also raised with the number of cigarettes smoked. It is strongly advised not to smoke. Do not use this drug if you smoke and are older than 35 years of age.

Serious side effects of Genora 1/50

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

  • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
  • Signs of liver problems like dark urine, feeling tired, not hungry, upset stomach or stomach pain, light-colored stools, throwing up, or yellow skin or eyes.
  • Coughing up blood.
  • Shortness of breath.
  • Chest pain or pressure.
  • Very bad dizziness or passing out.
  • Very upset stomach or throwing up.
  • Weakness on 1 side of the body, trouble speaking or thinking, change in balance, drooping on one side of the face, or blurred eyesight.
  • Swelling, warmth, numbness, change of color, or pain in a leg or arm.
  • Very bad headache.
  • Low mood (depression).
  • Feeling very tired or weak.
  • Very bad belly pain.
  • Swelling.
  • Bulging eyes.
  • Change in eyesight.
  • Change in how contact lenses feel in the eyes.
  • A lump in the breast, breast pain or soreness, or nipple discharge.
  • Vaginal itching or discharge.
  • Spotting or vaginal bleeding that is very bad or does not go away.

Other side effects of Genora 1/50

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

  • Feeling more or less hungry.
  • Dizziness.
  • Weight gain.
  • Headache.
  • Upset stomach or throwing up.
  • Cramps.
  • Bloating.
  • Enlarged breasts.
  • Breast soreness.
  • Period (menstrual) changes. These include spotting or bleeding between cycles.
  • This drug may cause dark patches of skin on your face. Avoid sun, sunlamps, and tanning beds. Use sunscreen and wear clothing and eyewear that protects you from the sun.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at

For Healthcare Professionals

Applies to mestranol/norethindrone: oral tablet.


The more commonly reported adverse effects of combined oral contraceptives include breakthrough bleeding/spotting, changes in menstrual flow, headache, dizziness, mood changes, nausea, vomiting, and breast pain.[Ref]


Combined Oral Contraceptives:

Very rare (less than 0.01%): Aggravation of varicose veins

Frequency not reported: Myocardial infarction, arterial thromboembolism, thrombophlebitis, hypertension, fluid retention, edema


Combined Oral Contraceptives:

Common (1% to 10%): Breast pain, tenderness, enlargement, secretion

Frequency not reported: Temporary infertility after discontinuation, premenstrual syndrome, diminution in lactation when given immediately postpartum


Combined Oral Contraceptives:

Very common (10% or more): Breakthrough bleeding/spotting

Common (1% to 10%): Dysmenorrhea, change in menstrual flow, change in cervical ectropion and secretion, amenorrhea, vaginitis, including candidiasis[Ref]

Nervous system

Combined Oral Contraceptives:

Very common (10% or more): Headache

Common (1% to 10%): Dizziness

Very rare (less than 0.01%): Exacerbation of chorea

Frequency not reported: Cerebral hemorrhage, cerebral thrombosis, migraines


Combined Oral Contraceptives:

Uncommon (0.1% to 1%): Changes in appetite (increase or decrease); changes in serum lipid levels (including hypertriglyceridemia)

Rare (0.01% to 0.1%): Glucose intolerance

Very rare (less than 0.01%): Exacerbation of porphyria, depressed serum folate levels

Frequency not reported: Reduced carbohydrate tolerance, vitamin B6 deficiency; weight changes (increase or decrease)


Combined Oral Contraceptives:

Common (1% to 10%): Nausea, vomiting, abdominal pain

Uncommon (0.1% to 1%): Abdominal cramps, bloating

Very rare (less than 0.01%): Pancreatitis, ischemic colitis, gall bladder disease including gallstones

Frequency not reported: Inflammatory bowel disease (Crohn's Disease, ulcerative colitis), dyspepsia, mesenteric thrombosis[Ref]


Combined Oral Contraceptives:

Rare (0.01% to 0.1%): Cholestatic jaundice

Frequency not reported: Budd-Chiari syndrome, hepatocellular injury (e.g., hepatitis, hepatic function abnormal), increased risk hepatic adenomas or benign liver tumors[Ref]


Some studies suggest that oral contraceptive use has been associated with an increase in the risk of cervical intraepithelial neoplasia in some populations of women. However, there continues to be controversy about the extent to which such findings may be due to differences in sexual behavior and other factors. Numerous studies have looked at the incidence of breast cancer and use of oral contraceptives. In a large, prospective cohort study (n=1.8 million; follow up 10.9 years), a small increased risk was reported in women using any hormonal contraceptive compared to women who had never used hormonal contraception. The absolute risk was reported as 1 extra breast cancer for every 7690 women using hormonal contraception for 1 year.[Ref]

Combined Oral Contraceptives:

Very rare (less than 0.01%): Hepatocellular carcinomas

Frequency not reported: Breast cancer, cervical intraepithelial neoplasia[Ref]


Combined Oral Contraceptives:

Common (1% to 10%): Nervousness, mood changes (including depression), changes in libido

Frequency not reported: Mental depression[Ref]


Combined Oral Contraceptives:

Very rare (less than 0.01%): Exacerbation of systemic lupus erythematosus


Combined Oral Contraceptives:

Rare (0.01% to 0.1%): Intolerance to contact lenses

Very rare (less than 0.01%): Optic neuritis, retinal vascular thrombosis

Frequency not reported: Changes in corneal curvature (steepening), cataracts, retinal thrombosis[Ref]


Combined Oral Contraceptives:

Frequency not reported: Pulmonary embolism


Combined Oral Contraceptives:

Very rare (less than 0.01%): Hemolytic uremic syndrome

Frequency not reported: Impaired renal function, cystitis-like syndrome


Combined Oral Contraceptives:

Common (1% to 10%): Acne

Uncommon (0.1% to 1%): Rash, chloasma (melasma), hirsutism, alopecia

Rare (0.01% to 0.1%): Erythema nodosum

Very rare (less than 0.01%): Erythema multiforme

Frequency not reported: Loss of scalp hair, hemorrhagic eruption, photosensitivity


Combined Oral Contraceptives:

Frequency not reported: Fatigue[Ref]


Combined Oral Contraceptives:

Rare (0.01% to 0.1%): Anaphylactic/anaphylactoid reactions, including very rare cases of urticaria, angioedema, and severe reactions with respiratory and circulatory symptoms


Combined Oral Contraceptives:

Frequency not reported: Muscle spasms, back pain

More about Genora 1 / 50 (mestranol / norethindrone)

Patient resources

Other brands

Necon 1/50, Norinyl 1+50

Related treatment guides


1. "Oral contraceptives and neoplasia. WHO Scientific Group." World Health Organ Tech Rep Ser 817 (1992): 1-46

2. Cerner Multum, Inc. "Australian Product Information." O 0

3. "Product Information. Necon 1/50 (mestranol-norethindrone)." Watson Pharmaceuticals (2019):

4. "Product Information. Ortho-Novum 1/35 (ethinyl estradiol-norethindrone)." Ortho McNeil Pharmaceutical

5. Morch LS, Skovlund CW, Hannaford PC, Iversen L, Fielding S, Lidegaard O "Contemporary hormonal contraception and the risk of breast cancer." N Engl J Med 377 (2017): 2228-39

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.