Interactions with supplements
Calcium
Magnesium
Vitamin D
Zinc
Look Up > Drugs > Megestrol Acetate
Megestrol Acetate
Pronunciation
U.S. Brand Names
Generic Available
Pharmacological Index
Use
Pregnancy Risk Factor
Contraindications
Warnings/Precautions
Adverse Reactions
Overdosage/Toxicology
Drug Interactions
Stability
Mechanism of Action
Pharmacodynamics/Kinetics
Usual Dosage
Monitoring Parameters
Test Interactions
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
References

Pronunciation
(me JES trole AS e tate)

U.S. Brand Names
Megace®

Generic Available

Yes


Pharmacological Index

Antineoplastic Agent, Miscellaneous; Progestin


Use

Palliative treatment of breast and endometrial carcinomas, appetite stimulation, and promotion of weight gain in cachexia


Pregnancy Risk Factor

X


Contraindications

Hypersensitivity to megestrol or any component; pregnancy


Warnings/Precautions

The U.S. Food and Drug Administration (FDA) currently recommends that procedures for proper handling and disposal of antineoplastic agents be considered. Use during the first few months of pregnancy is not recommended. Use with caution in patients with a history of thrombophlebitis. Elderly females may have vaginal bleeding or discharge and need to be forewarned of this side effect and inconvenience.


Adverse Reactions

>10%:

Cardiovascular: Edema

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

Neuromuscular & skeletal: Weakness

1% to 10%:

Central nervous system: Insomnia, depression, fever, headache

Dermatologic: Allergic rash with or without pruritus, melasma or chloasma, rash, and rarely alopecia

Endocrine & metabolic: Changes in cervical erosion and secretions, increased breast tenderness, changes in vaginal bleeding pattern, edema, fluid retention, hyperglycemia

Gastrointestinal: Weight gain (not attributed to edema or fluid retention), nausea, vomiting, stomach cramps

Hepatic: Cholestatic jaundice, hepatotoxicity

Hematologic: Myelosuppressive:

WBC: None

Platelets: None

Local: Thrombophlebitis

Neuromuscular & skeletal: Carpal tunnel syndrome

Respiratory: Hyperpnea


Overdosage/Toxicology

Toxicity is unlikely following simple exposures of excessive doses


Drug Interactions

No data reported


Stability

Megestrol acetate (Megace®) oral suspension is compatible with water, orange juice, apple juice, or Sustacal H.C. for immediate consumption


Mechanism of Action

A synthetic progestin with antiestrogenic properties which disrupt the estrogen receptor cycle. Megace® interferes with the normal estrogen cycle and results in a lower LH titer. May also have a direct effect on the endometrium. Megestrol is an antineoplastic progestin thought to act through an antileutenizing effect mediated via the pituitary.


Pharmacodynamics/Kinetics

Onset of action: At least 2 months of continuous therapy is necessary

Absorption: Oral: Well absorbed

Metabolism: Completely metabolized in the liver to free steroids and glucuronide conjugates

Time to peak serum concentration: Oral: Within 1-3 hours

Half-life, elimination: 15-20 hours

Elimination: In urine as steroid metabolites and inactive compound, some in feces and bile


Usual Dosage

Adults: Oral (refer to individual protocols):

Breast carcinoma: 40 mg 4 times/day

Endometrial: 40-320 mg/day in divided doses; use for 2 months to determine efficacy; maximum doses used have been up to 800 mg/day

Uterine bleeding: 40 mg 2-4 times/day

Male/Female: HIV-related cachexia: Initial dose: 800 mg/day; daily doses of 400 and 800 mg/day were found to be clinically effective

Dosing adjustment in renal impairment: No data available; however, the urinary excretion of megestrol acetate administered in doses of 4-90 mg ranged from 56% to 78% within 10 days

Hemodialysis: Megestrol acetate has not been tested for dialyzability; however, due to its low solubility, it is postulated that dialysis would not be an effective means of treating an overdose


Monitoring Parameters

Monitor for tumor response; observe for signs of thromboembolic phenomena; monitor for thromboembolism


Test Interactions

Altered thyroid and liver function tests


Mental Health: Effects on Mental Status

May cause insomnia or depression


Mental Health: Effects on Psychiatric Treatment

May rarely cause myelosuppression; use caution with clozapine and carbamazepine


Dental Health: Local Anesthetic/Vasoconstrictor Precautions

No information available to require special precautions


Dental Health: Effects on Dental Treatment

No effects or complications reported


Patient Information

Follow dosage schedule and do not take more than prescribed. You may experience sensitivity to sunlight (use sunblock, wear protective clothing, and avoid extended exposure to direct sunlight); dizziness, anxiety, depression (use caution when driving or engaging in tasks that require alertness until response to drug is known); change in appetite (maintain adequate hydration and diet - 2-3 L/day of fluids unless instructed to restrict fluid intake); decreased libido or increased body hair (reversible when drug is discontinued); hot flashes (cool clothes and environment may help). Report swelling of face, lips, or mouth; absence or altered menses; abdominal pain; vaginal itching, irritation, or discharge; heat, warmth, redness, or swelling of extremities; or sudden onset change in vision. Pregnancy/breast-feeding precautions: Inform prescriber if you are pregnant. Do not get pregnant during or for 1 month following therapy. Consult prescriber for instruction on appropriate contraceptive measures. This drug may cause severe fetal defects. Do not donate blood during or for 1 month following therapy (same reason). Do not breast-feed.


Nursing Implications

Monitor tumor response; observe for signs of thromboembolic phenomena


Dosage Forms

Suspension, oral: 40 mg/mL with alcohol 0.06% (236.6 mL)

Tablet: 20 mg, 40 mg


References

Canetta R, Florentine S, Hunter H, et al, "Megestrol Acetate," Cancer Treat Rev, 1983, 10(3);141-57.

Fietkau R, Riepl M, Kettner H, et al, "Supportive Use of Megestrol Acetate in Patients With Head and Neck Cancer During Radio(Chemo)Therapy," Eur J Cancer, 1997, 33(1):75-9.

Jeffrey LP, Chairman, National Study Commission on Cytotoxic Exposure. Position Statement. "The Handling of Cytotoxic Agents by Women Who Are Pregnant, Attempting to Conceive, or Breast-Feeding," January 12, 1987.

Lentz SS, Brady MF, Major FJ, et al, "High-Dose Megestrol Acetate in Advanced or Recurrent Endometrial Carcinoma: A Gynecologic Oncology Group Study," J Clin Oncol, 1996, 14(2):357-61.

Schacter L, Rozencweig M, Canett R, et al, "Megestrol Acetate: Clinical Experience," Cancer Treat Rev, 1989, 16(1):49-63.

Strang P, "The Effect of Megestrol Acetate on Anorexia, Weight Loss and Cachexia in Cancer and AIDS Patients," Anticancer Res, 1997, 17(1B):657-62.


Copyright © 1978-2000 Lexi-Comp Inc. All Rights Reserved