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Look Up > Drugs > Norethindrone
Norethindrone
Pronunciation
U.S. Brand Names
Generic Available
Synonyms
Pharmacological Index
Use
Pregnancy Risk Factor
Contraindications
Warnings/Precautions
Adverse Reactions
Drug Interactions
Mechanism of Action
Usual Dosage
Dietary Considerations
Mental Health: Effects on Mental Status
Mental Health: Effects on Psychiatric Treatment
Dental Health: Local Anesthetic/Vasoconstrictor Precautions
Dental Health: Effects on Dental Treatment
Patient Information
Nursing Implications
Dosage Forms

Pronunciation
(nor eth IN drone)

U.S. Brand Names
Aygestin®; Micronor®; NOR-QD®

Generic Available

No


Synonyms
Norethindrone Acetate; Norethisterone

Pharmacological Index

Contraceptive; Progestin


Use

Treatment of amenorrhea; abnormal uterine bleeding; endometriosis, oral contraceptive; higher rate of failure with progestin only contraceptives


Pregnancy Risk Factor

X


Contraindications

Hypersensitivity to norethindrone; thromboembolic disorders; severe hepatic disease; breast cancer; undiagnosed vaginal bleeding


Warnings/Precautions

Use of any progestin during the first 4 months of pregnancy is not recommended. Discontinue if sudden partial or complete loss of vision, proptosis, diplopia, or migraine occur. There is a higher rate of failure with progestin only contraceptives. Progestin-induced withdrawal bleeding occurs within 3-7 days after discontinuation of drug. Use with caution in patients with asthma, diabetes, seizure disorder, migraine, cardiac or renal dysfunction, or psychic depression.


Adverse Reactions

>10%:

Cardiovascular: Edema

Endocrine & metabolic: Breakthrough bleeding, spotting, changes in menstrual flow, amenorrhea

Gastrointestinal: Anorexia

Local: Pain at injection site

Neuromuscular & skeletal: Weakness

1% to 10%:

Cardiovascular: Edema

Central nervous system: Mental depression, fever, insomnia

Dermatologic: Melasma or chloasma, allergic rash with or without pruritus

Endocrine & metabolic: Increased breast tenderness

Gastrointestinal: Weight gain or loss

Genitourinary: Changes in cervical erosion and secretions

Hepatic: Cholestatic jaundice


Drug Interactions

Decreased effect: Aminoglutethimide may decrease effects by increasing hepatic metabolism. Nelfinavir decreases norethindrone concentrations.


Mechanism of Action

Inhibits secretion of pituitary gonadotropin (LH) which prevents follicular maturation and ovulation


Usual Dosage

Adolescents and Adults: Female: Oral:

Amenorrhea and abnormal uterine bleeding:

Norethindrone: 5-20 mg/day on days 5-25 of menstrual cycle

Acetate salt: 2.5-10 mg on days 5-25 of menstrual cycle

Endometriosis:

Norethindrone: 10 mg/day for 2 weeks; increase at increments of 5 mg/day every 2 weeks until 30 mg/day; continue for 6-9 months or until breakthrough bleeding demands temporary termination

Acetate salt: 5 mg/day for 14 days; increase at increments of 2.5 mg/day every 2 weeks up to 15 mg/day; continue for 6-9 months or until breakthrough bleeding demands temporary termination


Dietary Considerations

Limit caffeine; high-dose vitamin C (1 g/day) may increase adverse effects; increase dietary intake of folate and pyridoxine; should be taken with food at same time each day


Mental Health: Effects on Mental Status

May cause insomnia or depression


Mental Health: Effects on Psychiatric Treatment

None reported


Dental Health: Local Anesthetic/Vasoconstrictor Precautions

No information available to require special precautions


Dental Health: Effects on Dental Treatment

Until we know more about the mechanism of interaction, caution is required in prescribing antibiotics to female dental patients taking progestin-only oral contraceptives


Patient Information

Take according to prescribed schedule. Follow instructions for regular self-breast exam. You may experience dizziness or lightheadedness; use caution when driving or engaging in tasks that require alertness until response to drug is known. Limit intake of caffeine. Avoid high-dose vitamin C, folate, or pyridoxine. You may experience photosensitivity; use sunscreen, wear protective clothing and eyewear, and avoid direct sunlight. You may experience loss of hair (reversible), weight gain or loss. Report sudden severe headache or vomiting, disturbances of vision or speech, sudden blindness, numbness of weakness in an extremity, chest pain, calf pain, respiratory difficulty, depression or acute fatigue, unusual bleeding, spotting, or changes in menstrual flow. Pregnancy/breast-feeding precautions: Inform prescriber if pregnant. Consult prescriber if breast-feeding.


Nursing Implications

Norethindrone acetate is ~2 times as potent as norethindrone


Dosage Forms

Tablet: 0.35 mg, 5 mg

Tablet, as acetate: 5 mg


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