FLUOXYMESTERONE

FLUOXYMESTERONE (floo-ox-ee-mess'te-rone) Halotestin, Ora Testryl  Classifications: hormone; androgen/anabolic steroid; Therapeutic: anabolic steroid; male hormone replacement Prototype: Testosterone Pregnancy Category: X Controlled Substance: Schedule III

Availability

2 mg, 5 mg, 10 mg tablets

Action

Short-acting, orally effective derivative of testosterone with hypercholesterolemic effect. Retention of sodium is minimal; thus, hypertension and edema rarely complicate therapy.

Therapeutic Effect

Replacement therapy for endogenous testosterone. Promotes recalcification of osseous metastases and regression of soft tissue lesions.

Uses

In men as replacement therapy in conditions associated with testicular hormone deficiency; in women to antagonize effects of estrogen in androgen-responsive inoperable breast cancer. Also in combination with estrogens for management of severe postmenopausal vasomotor symptoms.

Contraindications

Breast cancer in men, prostatic cancer, benign obstructive prostatic hypertrophy; hypercalcemia; diabetes mellitus; severe cardiorenal disease or liver damage; nephrosis or nephrotic phase of nephritis; history of MI; athletes; infants; women with inoperable mammary cancer <1 y or >5 y after menopause; pregnancy (category X), lactation.

Cautious Use

Children, older males, history of MI, or coronary disease, hepatic, renal or congestive heart failure, women.

Route & Dosage

Male Hypogonadism Adult: PO 2.5–20 mg/d Metastatic Carcinoma of Female Breast Adult: PO 10–40 mg/d in divided doses Postpartum Breast Engorgement Adult: PO 2.5 mg shortly after delivery, then 5–10 mg/d in divided doses for 4–5 d

Administration

Oral

• Give immediately before or with meals to diminish GI distress.

Adverse Effects (≥1%)

Endocrine: Virilization (women), gynecomastia (men). Urogenital: Priapism, impotence. Metabolic: Jaundice (reversible), hypoglycemia, hypercalcemia. GI: Hepatocellular carcinoma, peliosis hepatitis, nausea, vomiting, diarrhea, symptoms resembling peptic ulcer. Body as a Whole: Anaphylactic reactions (rare), edema, acne.

Interactions

Drug: oral anticoagulants increase risk of bleeding. Possibly increases risk of cyclosporine toxicity. Insulin and oral hypoglycemic agents may decrease glucose level; dose will need to be adjusted. Herbal: Echinacea may increase hepatotoxicity.

Pharmacokinetics

Absorption: Readily from GI tract. Metabolism: In liver. Half-Life: 9.5 h.

Nursing Implications

Assessment & Drug Effects

• Lab test: Obtain baseline and periodic liver function and serum electrolytes, Hgb, Hct, and serum and urine calcium; also serial serum cholesterol in patients with history of MI or coronary artery disease.
• Monitor I&O ratio and pattern and weight, and check for edema; report significant changes.
• Monitor for S&S of hypercalcemia (see Appendix F); particularly likely in patients with metastatic breast carcinoma. Stop anabolic therapy if it develops.
• Be alert for voice change in female patient, an early sign of virilism. Virilism may be irreversible even after prompt discontinuation of therapy.
• Note: When used in pediatric patients, therapy is preceded by x-ray of wrist bones to establish level of bone maturation. During treatment, bone maturation may proceed more rapidly than linear growth; therefore, intermittent dosage schedule and periodic x-rays are usual.
• Observe children <7 y closely for precocious development of male sexual characteristics or masculinization because they are particularly sensitive to androgenic effects.
• Watch for symptoms of hypoglycemia (see Appendix F) and report to physician. Anabolic treatment may reduce blood glucose in diabetic patients.
• Observe patient on concomitant anticoagulant therapy for ecchymotic areas, petechiae, or abnormal bleeding from any site. Close monitoring of PT & INR is essential.
• Note: When used for palliation of mammary cancer, subjective effects of therapy may not be experienced for 1 mo; objective symptoms may be delayed for as long as 3 mo.
• Be aware that anabolic response may be evidenced by euphoria and gain in weight and appetite, especially in emaciated and debilitated patient.

Patient & Family Education

• Adhere to scheduled appointments for laboratory tests.
• Good personal hygiene, including meticulous skin care is very important (females and prepubertal males are especially likely to develop acne).
• Note and report symptoms of jaundice (see Appendix F) to physician. Dose adjustment may reverse the condition.
• Report menstrual irregularities.
• Keep child's appointments for bone maturation studies (usually every 3–6 mo) to prevent compromised adult height.
• Report priapism (prolonged erection) to physician promptly, it is a symptom of overdosage. A temporary interruption of regimen may be indicated. Also report persistent GI distress, diarrhea, or the onset of jaundice.
• Be aware that virilization usually occurs. Report to physician any voice change (hoarseness or deepening), increased libido (associated with clitoral enlargement), hirsutism immediately. Usually, stopping therapy will end further development of symptoms but will not reverse hirsutism or voice change.

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Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug