(redirected from Megace OS)
Also found in: Dictionary, Thesaurus.
Related to Megace OS: Megace ES


a synthetic progestational agent administered orally as an antineoplastic agent for palliative treatment of recurrent, inoperable, or metastatic carcinoma of the breast or endometrium and for the treatment of anorexia, cachexia, and weight loss in patients with cancer or acquired immunodeficiency syndrome.


(me-jess-trole) ,


(trade name),

Megace ES

(trade name),

Megace OS

(trade name)


Therapeutic: antineoplastics
Pharmacologic: progestins
Pregnancy Category: D (tablets)
Pregnancy Category: X (suspension)


Palliative treatment of endometrial and breast carcinoma, either alone or with surgery or radiation (tablets only).Treatment of anorexia, weight loss, and cachexia associated with AIDS (oral suspension only).


Antineoplastic effect may result from inhibition of pituitary function.

Therapeutic effects

Regression of tumor.
Increased appetite and weight gain in patients with AIDS.


Absorption: Well absorbed from the GI tract.
Distribution: Unknown.
Protein Binding: ≥90%.
Metabolism and Excretion: Completely metabolized by the liver.
Half-life: 38 hr (range 13–104 hr).

Time/action profile (antineoplastic activity)

POwk–mos2 mounknown


Contraindicated in: Hypersensitivity;Undiagnosed vaginal bleeding;Severe liver disease;Suspension contains alcohol and should be avoided in patients with known intolerance; Obstetric / Lactation: Pregnancy or lactation.
Use Cautiously in: Diabetes;Mental depression;Renal disease;History of thrombophlebitis;Cardiovascular disease;Seizure disorders.

Adverse Reactions/Side Effects


  • thromboembolism (life-threatening)
  • edema


  • GI irritation


  • alopecia


  • asymptomatic adrenal suppression (chronic therapy) (most frequent)


  • vaginal bleeding


  • thrombophlebitis


  • carpal tunnel syndrome


Drug-Drug interaction

None significant.


Oral (Adults) Breast carcinoma—160 mg/day single dose or divided doses; endometrial/ovarian carcinoma—40–320 mg/day in divided doses; anorexia associated with AIDS—800 mg day; may ↓ to 400 mg/day after 1 mo (range 400–800 mg/day).

Availability (generic available)

Tablets: 20 mg, 40 mg
Oral suspensionlemon-lime flavor: 40 mg/mL, 125 mg/mL (Megace ES)

Nursing implications

Nursing assessment

  • Assess for swelling, pain, or tenderness in legs. Report these signs of deep vein thrombophlebitis.
  • Anorexia: Monitor weight, appetite, and nutritional intake in patients with AIDS.

Potential Nursing Diagnoses

Imbalanced nutrition: less than body requirements (Indications)


  • Because of high dose, suspension is most convenient form for patients with AIDS.
    • Do not confuse Megace 800 mg/20 mL with Megace ES 625 mg/5 mL.
  • Oral: May be administered with meals if GI irritation becomes a problem.

Patient/Family Teaching

  • Instruct patient to take medication exactly as directed; do not skip or double up on missed doses. Missed doses may be taken as long as it is not right before next dose. Gradually decrease dose prior to discontinuation.
  • Advise patient to report to health care professional any unusual vaginal bleeding or signs of deep vein thrombophlebitis.
  • Discuss with patient the possibility of hair loss. Explore methods of coping.
  • Advise patient that this medication may have teratogenic effects. Contraception should be used during therapy and for at least 4 mo after therapy is completed. Advise patient to notify health care professional immediately if pregnancy is planned or suspected or if breast feeding.

Evaluation/Desired Outcomes

  • Slowing or arresting the spread of endometrial or breast malignancy. Therapeutic effects usually occur within 2 mo of initiating therapy.
  • Increased appetite and weight gain in patients with AIDS.


/me·ges·trol/ (mĕ-jes´trol) a synthetic progestational agent, used as the acetate ester in the palliative treatment of some breast, endometrial, and prostate carcinomas and in the treatment of anorexia, cachexia, and weight loss associated with cancer or AIDS.


A PROGESTOGEN drug used to assist in the treatment of breast or endometrial cancer. A brand name is Megace.