norethindrone acetate

norethindrone acetate (nôreth´indrōn´ as´tāt),

n brand names: Aygestin, Micronor, Norlutate, Norlutin, Nor-QD;
drug class: progesterone derivative;
action: inhibits secretion of pituitary gonadotropins, which prevents follicular maturation, ovulation;
uses: abnormal uterine bleeding, amenorrhea, endometriosis, contraceptive.

---

norethindrone acetate

Aygestin

Pharmacologic class: Progesterone, hormone

Therapeutic class: Progestin

Pregnancy risk category X

Action

Inhibits pituitary gonadotropin secretion, suppressing follicular maturation and ovulation and stimulating mammary tissue growth

Availability

Tablets: 5 mg

⊘Indications and dosages

➣ Endometriosis

Adults: 5 mg P.O. daily for 2 weeks, increased in increments of 2.5 mg/day q 2 weeks until 15 mg daily is reached

➣ Amenorrhea; abnormal uterine bleeding

Adults: 2.5 to 10 mg P.O. daily starting on day 5 of menstrual cycle

Contraindications

• Hypersensitivity to drug
• Severe hepatic disease
• Thromboembolic disorders
• Breast or reproductive tract cancer
• Undiagnosed vaginal bleeding
• Missed abortion
• Pregnancy

Precautions

Use cautiously in:
• hypertension, blood dyscrasias, bone marrow disease, hepatic or renal disease, gallbladder disease, heart failure, diabetes mellitus, depression, migraine, asthma, seizure disorder
• family history of breast or reproductive tract cancer
• breastfeeding patients.

Administration

• Give with or without food.
• Know therapy may continue for 6 to 9 months or until breakthrough bleeding necessitates a temporary halt.

Route	Onset	Peak	Duration
P.O.	Variable	Unknown	24 hr

Adverse reactions

CNS: migraine, depression, insomnia, drowsiness

EENT: retinal vascular lesions, sudden partial or complete vision loss, proptosis, diplopia, papilledema

GI: nausea

GU: breakthrough bleeding, menstrual flow changes, amenorrhea, changes in cervical erosion and secretions, breast tenderness and secretion

Hepatic: cholestatic jaundice

Metabolic: fluid retention, decreased glucose tolerance

Skin: rash, urticaria, acne, hirsutism, chloasma

Other: edema, weight gain or loss, fever

Interactions

Drug-drug. Hepatic enzyme-inducing drugs (such as carbamazepine, phenobarbital, phenytoin, rifampin): decreased norethindrone efficacy

Drug-diagnostic tests. Alkaline phosphatase; amino acids; factors VII, VIII, IX, and X; nitrogen; pregnanediol: increased levels

Gamma-glutamyltransferase, high-density lipoproteins: decreased levels

Drug-herbs. Cola nut, guarana, yerba maté: increased CNS stimulation

St. John's wort: decreased contraceptive efficacy

Drug-behaviors. Smoking: risk of serious cardiovascular reactions

Patient monitoring

• Monitor pretreatment and annual physical exams to check blood pressure, breasts, abdomen, pelvic organs, and Pap smear results.
☞ Assess for signs and symptoms of depression, especially in patients with history of depression. Stop giving drug if significant depression recurs.
• Check blood glucose level in diabetic patients.

Patient teaching

• Instruct patient to avoid pregnancy or to discontinue drug if she gets pregnant (may cause serious fetal anomalies or fetal death).
☞ Advise patient to discontinue drug and consult prescriber if she experiences sudden partial or complete vision loss.
• If patient is receiving drug to treat amenorrhea, tell her to mark administration days on calendar.
• Tell diabetic patient to monitor blood glucose level closely and to watch for hyperglycemia.
• Instruct patient to report breakthrough bleeding, spotting, change in menstrual flow, or amenorrhea.
• Caution patient not to smoke during therapy.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, herbs, and behaviors mentioned above.