MEDROXYPROGESTERONE ACETATE

MEDROXYPROGESTERONE ACETATE (me-drox'ee-proe-jess'te-rone) Depo-Provera, Depo-subQ Provera 104, Provera Classifications: hormone; progestin; Therapeutic: progestin Prototype: Progesterone Pregnancy Category: X

Availability

2.5 mg, 5 mg, 10 mg tablets; 104 mg/0.65 mL, 150 mg/mL, 400 mg/mL injection

Action

Induces and maintains endometrium, preventing uterine bleeding; inhibits production of pituitary gonadotropin, thus preventing ovulation and producing thick cervical mucus resistant to passage of sperm.

Therapeutic Effect

Slows release of luteinizing hormone (LH) preventing follicular maturation and ovulation. Has prolonged, variable duration of action and androgenic and antiestrogenic activity.

Uses

Dysfunctional uterine bleeding; secondary amenorrhea; parenteral form (Depo-Provera) used in adjunctive, palliative treatment of inoperable, recurrent, and metastatic endometrial or renal carcinoma; contraception; endometriosis-associated pain.

Unlabeled Uses

Obstructive sleep apnea.

Contraindications

History of thromboembolic disorders; breast cancer, cervical cancer, uterine cancer, vaginal cancer; hepatic disease; abnormal vaginal bleeding, incomplete abortion; pregnancy (category X).

Cautious Use

Asthma, seizure disorders, CVA; migraine, cardiac or kidney dysfunction, liver disease.

Route & Dosage

Secondary Amenorrhea Adult: PO 5–10 mg/d for 5–10 d beginning any time if endometrium is adequately estrogen primed (withdrawal bleeding occurs in 3–7 d after discontinuing therapy) Abnormal Bleeding Due to Hormonal Imbalance Adult: PO 5–10 mg/d for 5–10 d beginning on the assumed or calculated 16th or 21st d of menstrual cycle; if bleeding is controlled, administer 2 subsequent cycles Carcinoma Adult: IM 400–1000 mg/wk; continue at 400 mg/mo if improvement occurs and disease stabilizes Contraceptive Adult: IM 100 mg q3mo Sleep Apnea Adult: PO 20 mg t.i.d.

Administration

Oral

• Oral drug may be given with food to minimize GI distress.

Intramuscular

• Administer IM deep into a large muscle.
• Store both formulations at 15°–30° C (59°–86° F); protect from freezing.

Adverse Effects (≥1%)

CNS: Cerebral thrombosis or hemorrhage, depression. CV: Hypertension, pulmonary embolism, edema. GI: Vomiting, nausea, cholestatic jaundice, abdominal cramps. Urogenital: Breakthrough bleeding, changes in menstrual flow, dysmenorrhea, vaginal candidiasis. Skin: Angioneurotic edema. Body as a Whole: Weight changes; breast tenderness, enlargement or secretion. Musculoskeletal: Loss of bone mineral density.

Interactions

Drug: Aminoglutethimide decreases serum concentrations of medroxyprogesterone; barbiturates, carbamazepine, oxcarbazepine, phenytoin, primidone, rifampin, modafinil, rifabutin, topiramate can increase metabolism and decrease serum levels of medroxyprogesterone. Herbal: Intermenstrual bleeding and loss of contraceptive efficacy may occur with St. John's wort.

Pharmacokinetics

Peak: 2–4 h PO, 3 wk IM. Distribution: >90% protein bound. Metabolism: In liver. Elimination: Primarily in feces. Half-Life: 30 d PO, 50 d IM.

Nursing Implications

Assessment & Drug Effects

• See progesterone for numerous additional nursing implications.
• Be aware that IM injection may be painful. Monitor sites for evidence of sterile abscess. A residual lump and discoloration of tissue may develop.
• Monitor for S&S of thrombophlebitis (see Appendix F).
• Note: Planned menstrual cycling with medroxyprogesterone may benefit the patient with a history of recurrent episodes of abnormal uterine bleeding.

Patient & Family Education

• Be aware that after repeated IM injections, infertility and amenorrhea may persist as long as 18 mo.
• Learn breast self-examination.
• Review package insert to ensure complete understanding of progestin therapy.

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Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug