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Pronunciation |
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(me
JES trole AS e
tate) |
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U.S. Brand
Names |
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Megace® |
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Generic
Available |
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Yes |
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Pharmacological Index |
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Antineoplastic Agent, Miscellaneous; Progestin |
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Use |
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Palliative treatment of breast and endometrial carcinomas, appetite
stimulation, and promotion of weight gain in cachexia |
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Pregnancy Risk
Factor |
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X |
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Contraindications |
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Hypersensitivity to megestrol or any component;
pregnancy |
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Warnings/Precautions |
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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. |
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Adverse
Reactions |
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>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 |
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Overdosage/Toxicology |
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Toxicity is unlikely following simple exposures of excessive
doses |
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Drug
Interactions |
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No data reported |
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Stability |
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Megestrol acetate (Megace®) oral suspension is
compatible with water, orange juice, apple juice, or Sustacal H.C. for immediate
consumption |
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Mechanism of
Action |
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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. |
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Pharmacodynamics/Kinetics |
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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 |
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Usual Dosage |
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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 |
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Monitoring
Parameters |
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Monitor for tumor response; observe for signs of thromboembolic phenomena;
monitor for thromboembolism |
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Test
Interactions |
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Altered thyroid and liver function tests |
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Mental Health: Effects
on Mental Status |
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May cause insomnia or depression |
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Mental Health:
Effects on Psychiatric
Treatment |
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May rarely cause myelosuppression; use caution with clozapine and
carbamazepine |
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Dental Health: Local
Anesthetic/Vasoconstrictor
Precautions |
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No information available to require special precautions |
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Dental Health:
Effects on Dental Treatment |
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No effects or complications reported |
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Patient
Information |
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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. |
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Nursing
Implications |
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Monitor tumor response; observe for signs of thromboembolic
phenomena |
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Dosage Forms |
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Suspension, oral: 40 mg/mL with alcohol 0.06% (236.6 mL)
Tablet: 20 mg, 40 mg |
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References |
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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. |
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