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megestrol (Megace)
Tradename: Megace. Pregnancy risk category: X
Indications:
- appetite stimulation ( AIDS anorexia)
- palliative therapy for advanced breast cancer, ovarian cancer [7] & endometrial carcinoma*
* does not improve quality of life or mortality in cance patients [4]
Contraindications: Caution:
1) risk to fetus in 1st 4 months of pregnancy
2) photosensitivity: wear protective clothing or use sunscreen
Dosage:
1) start: 80-160 mg daily in 4 divided doses
2) maintenance: 400-800 mg PO QD
3) up to 1600 mg/day
Tablets: 20 mg, 40 mg
Suspension: 40 mg/mL in alcohol 0.06% (240 mL)
Adverse effects:
1) common (> 10%)
- breakthrough bleeding, spotting, changes in menstrual flow, amenorrhea, pain at site of injection, anorexia, edema, weakness
2) less common (1-10%)
- depression, fever, melasma, chloasma, allergic rash withor without pruritus, cholestatic jaundice, changes in cervical secretions, weight gain or loss, insomnia, breast tenderness, deep vein thrombophlebitis, carpal tunnel syndrome, alopecia, hyperpnea
3) other
- diarrhea
- nausea
- impotence/decreased libido/low testosterone
- headache
- hot flashes
- flushing
- photosensitivity
- visual changes
- migraine headache
4) adverse effects of abrupt discontinuation: [5]
- adrenal insufficiency may occur after long-term use [4,6]
- features of adrenal insufficiency & Cushing's syndrome may be present [9]
- thromboembolism
- breakthrough vaginal bleeding
- peripheral edema
- hyperglycemia
- hypertension
- alopecia
Test interactions: altered thyroid & liver function tests
Laboratory:
- megestrol acetate in serum/plasma
- megestrol acetate in urine
Mechanism of action:
1) progestin
2) may directly or indirectly stimulate appetite
3) may alter metabolic pathways that increase weight gain
4) does NOT increase lean tissue mass
5) weight gain is due to increase in fatty tissue only
6) may suppress hypothalamic-pituitary-adrenal axis
7) activates glucocorticoid receptors
Interactions
drug adverse effects of psychotropic agents
General
antineoplastic endocrine agent
progestational agent
Properties
MISC-INFO: elimination route LIVER
pregnancy-category D
X
safety in lactation ?
Database Correlations
PUBCHEM correlations
References
- The Pharmacological Basis of Therapeutics, 9th ed.
Gilman et al, eds. Permagon Press/McGraw Hill, 1996
- Drug Information & Medication Formulary, Veterans Affairs,
Central California Health Care System, 1st ed., Ravnan et al
eds, 1998
- Kaiser Permanente Northern California Regional Drug
Formulary, 1998
- Medical Knowledge Self Assessment Program (MKSAP) 11, 16, 18, 19
American College of Physicians, Philadelphia 1998, 2012, 2018, 2022
- Bruera & Neumann Canadian Medical Assoc. J (CAMJ):158:1717,
1998
- Leinung MC, Liporace R, Miller CH.
Induction of adrenal suppression by megestrol acetate in
patients with AIDS.
Ann Intern Med. 1995 Jun 1;122(11):843-5.
PMID: 7741369
- Deprecated Reference
- Ruiz Garcia V, Lapez-Briz E, Carbonell Sanchis R et al
Megestrol acetate for treatment of anorexia-cachexia syndrome.
Cochrane Database Syst Rev. 2013 Mar 28;(3):CD004310. Review.
PMID: 23543530
- Geriatric Review Syllabus, 10th edition (GRS10)
Harper GM, Lyons WL, Potter JF (eds)
American Geriatrics Society, 2019