Hormone Replacement Therapy

Fluoxymesterone is a synthetic androgenic anabolic solution and is approximately 5 times as potent as natural methyltestosterone. Like testosterone and other androgenic hormones, fluoxymesterone produces retention of nitrogen, potassium, and phosphorus; increases protein anabolism; and decreases amino acid catabolism. The antitumour activity of fluoxymesterone appears related to reduction or competitive inhibition of prolactin receptors or estrogen receptors or production. Clinical effects are most often seen in patients with either demonstrated steroid receptors or a history of prior response to other endocrine treatments.

Serum cholesterol levels may be altered. Caution is required in administering to patients with history of coronary artery disease.

Contraindicated in males with cancer of the prostate.

Fluoxymesterone is contraindicated during pregnancy due to possible masculinization of the fetus. Breast feeding is not recommended due to the potential secretion into breast milk.

Side Effects

Organ site side effect onset:
- cardiovascular mild fluid retention E 
- dermatologic acne E and D 
- endocrine amenorrhea, menstrual irregularities E and D 
- increased or decreased libido E 
- masculine traits in women (virilization) (35-40%) D 
- gastrointestinal nausea and vomiting (rare) I 
- increased appetite, weight gain E 
- hematologic suppression of clotting factors II, V, VII, X D 
- polycythemia (rare) D 
- hepatic elevated liver function tests E 
- cholestatic jaundice (rare) D
- hypersensitivity Type I (anaphylactoid), contains tartrazine I 
- neoplastic liver cancer L 
- renal/metabolic hypercalcemia E 
- decreased insulin requirements (in diabetics) E 
- protein anabolic effect with retention of nitrogen, potassium, calcium, phosphorus E 
- cholesterol (increase) E 

Dose-limiting side effects are underlined.
I = immediate (onset in hours to days); E = early (days to weeks);
D = delayed (weeks to months); L = late (months to years)

Virilization is the most common effect. Deepening of the voice, clitoral enlargement, growth of facial hair and male pattern baldness may be the most distressing side effects for female patients. If treatment is discontinued at the first signs, effects may slowly subside. Continuing therapy in the presence of obvious signs of masculinization may result in irreversible effects. Menstrual irregularities and amenorrhea may occur.

These effects may be reversible if the drug is discontinued promptly. Continued treatment may result in irreversible masculinization. Some virilization may be tolerated by the patient during treatment for breast cancer. 

Hypercalcemia may develop both spontaneously and as a result of hormonal therapy in women with disseminated breast carcinoma. If this occurs, the drug should be discontinued.

Hypercalcemia may occur in patients who are bedridden or have bony metastases. Signs include fatigue, weakness, nausea and vomiting, loss of appetitie (anorexia), thirst (polydypsia) and frequent voiding (polyuria).

Supply and Storage

Tablets 5 mg; store at room temperature; contain tartrazine.

Dosage Guidelines

Refer to protocol by which patient is being treated.

Adults Oral: bid-tid: 5-10 mg po

Adequate trial: subjective response in 1 month and objective response in 2-3 months

Dosage in myelosuppression: no adjustment required

Dosage in renal failure: no adjustment required

Dosage in hepatic failure: adjustment required, no details found

Immediate
(hours to days) * anaphylaxis (rare) 
nausea and vomiting (rare) 
Early
(days to weeks) loss of menstruation (menstrual irregularities, amenorrhea) 
masculine traits in women (virilization) 
increased appetite, weight gain 
liver problems (elevated liver function tests) 
skin problems (acne) 
increased serum calcium levels (hypercalcemia, in breast cancer) 
loss of diabetic control 
fluid retention (mild) 
protein anabolic effects (retention of nitrogen, potassium, calcium, phosphorus) 
increased serum cholesterol levels
Delayed/Late
(weeks to years) loss of menstruation (amenorrhea) 
acne 
blood problems (clotting factor suppression, polycythemia) 
* liver problems (cholestatic jaundice, rare) 
* liver cancer 

Contraindications

Known hypersensitivity to fluoxymesterone 
pregnancy and breast feeding 
males with prostate cancer 

Significant Interactions

Warfarin (Coumadin®)

Common Trade Name

Halotestin®