MEGESTROL ACETATE
(me-jess'trole)
Megace, Megace ES
Classifications: antineoplastic; hormone and synthetic substitute; progestin
Prototype: Progesterone
Pregnancy Category: X

Availability

40 mg/mL, 125 mg/mL suspension; 20 mg, 40 mg tablets

Actions

Progestational hormone with antineoplastic properties. Mechanism of action unclear; however, an antiluteinizing effect mediated via the pituitary has been postulated.

Therapeutic Effects

Moderate disease effects. Local effect when instilled directly into the endometrial cavity.

Uses

Palliative agent for treatment of advanced carcinoma of breast or endometrium. AIDS-related wasting or cachexia.

Contraindications

Diagnostic test for pregnancy; use in neoplastic diseases other than cancer of endometrium and breast; first 4 mo of pregnancy (category X).

Route & Dosage

Palliative Treatment for Advanced Breast Cancer
Adult: PO 40 mg q.i.d.

Palliative Treatment for Advanced Endometrial Cancer
Adult: PO 40–320 mg/d in divided doses

Appetite Stimulation
Adult: PO 200 mg q6h

HIV-Related Cachexia
Adult:: PO (suspension) 800 mg q.d. or 625 mg of Megace ES

Administration

Oral

Give with meals or food if GI distress occurs.
Shake oral suspension well before use.
Store at 15°–30° C (59°–86° F) in tightly closed container.

Adverse Effects (1%)

Urogenital: Vaginal bleeding. Body as a Whole: Breast tenderness, headache, increased appetite, weight gain, allergic-type reactions (including bronchial asthma). GI: Abdominal pain, nausea, vomiting. Hematologic: DVT.

Interactions

Drug: May increase levels of warfarin; may decrease renal clearance of dofetilide.

Pharmacokinetics

Absorption: Appears to be well absorbed from GI tract. Onset: Onset of objective response in breast cancer in 6–8 wk. Peak: 1–3 h. Duration: 3–12 mo. Metabolism: Completely metabolized in liver. Elimination: 57–78% of dose excreted in urine within 10 d.

Nursing Implications

Assessment & Drug Effects

Monitor weight periodically.
Notify physician if abdominal pain, headache, nausea, vomiting, or breast tenderness become pronounced.
Monitor for allergic reactions, including breathing distress characteristic of asthma, rash, urticaria, anaphylaxis, tachypnea, anxiety. Stop medication if they appear and notify physician.

Patient & Family Education

Use contraception measures during therapy for carcinoma.
Learn breast self-examination.
Learn S&S of thrombophlebitis (see Appendix F).
Review package insert to ensure understanding of megestrol therapy.

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