HALOTESTIN Tablets contain fluoxymesterone, an androgenic hormone.

Fluoxymesterone is a white or nearly white, odorless, crystalline powder, melting at or about 240° C, with some decomposition. It is practically insoluble in water, sparingly soluble in alcohol, and slightly soluble in chloroform.

The chemical name for fluoxymesterone is androst-4-en-3-one, 9-fluoro-11,17-dihydroxy-17-methyl-, (11β,17β)-. The molecular formula is C20H29FO3 and the molecular weight 336.45.

Endogenous androgens are responsible for normal growth and development of the male sex organs and for maintenance of secondary sex characteristics. These effects include growth and maturation of the prostate, seminal vesicles, penis, and scrotum; development of male hair distribution, such as beard, pubic, chest, and axillary hair; laryngeal enlargement, vocal cord thickening, and alterations in body musculature and fat distribution. Drugs in this class also cause retention of nitrogen, sodium, potassium, and phosphorus, and decreased urinary excretion of calcium. Androgens have been reported to increase protein anabolism and decrease protein catabolism. Nitrogen balance is improved only when there is sufficient intake of calories and protein.

Androgens are responsible for the growth spurt of adolescence and for eventual termination of linear growth, brought about by fusion of the epiphyseal growth centers. In children, exogenous androgens accelerate linear growth rates, but may cause disproportionate advancement in bone maturation. Use over long periods may result in fusion of the epiphyseal growth centers and termination of the growth process. Androgens have been reported to stimulate production of red blood cells by enhancing production of erythropoietic stimulation factor.

During exogenous administration of androgens, endogenous testosterone release is inhibited through feedback inhibition of pituitary luteinizing hormone (LH). At large doses of exogenous androgens, spermatogenesis may also be suppressed through feedback inhibition of pituitary follicle stimulating hormone (FSH).

Inactivation of testosterone occurs primarily in the liver.

The half-life of fluoxymesterone after oral administration is approximately 9.2 hours.

Fluoxymesterone is a synthetic androgenic anabolic steroid and is approximately 5 times as potent as natural methyltestosterone. Like testosterone and other androgenic hormones, fluoxymesterone binds to the androgen receptor. It produces retention of nitrogen, sodium, potassium, and phosphorus; increases protein anabolism; decreases amino acid catabolism and decreased urinary excretion of calcium. The antitumour activity of fluoxymesterone appears related to reduction or competitive inhibition of prolactin receptors or estrogen receptors or production.

Women should be observed for signs of virilization which is usual following androgen use at high doses. Discontinuation of drug therapy at the time of evidence of mild virilism is necessary to prevent irreversible virilization. A decision may be made by the patient and the physician that some virilization will be tolerated during treatment for breast carcinoma.

Patients with benign prostatic hypertrophy may develop acute urethral obstruction. Priapism or excessive sexual stimulation may develop. Oligospermia may occur after prolonged administration or excessive dosage. If any of these effects appear, the androgen should be stopped and if restarted, a lower dosage should be utilized.

This product contains FD&C Yellow No. 5 (tartrazine) which may cause allergic-type reactions (including bronchial asthma) in certain susceptible individuals. Although the overall incidence of FD&C Yellow No. 5 (tartrazine) sensitivity in the general population is low, it is frequently seen in patients who also have aspirin hypersensitivity.

Androgens may increase sensitivity to oral anticoagulants. Dosage of the anticoagulant may require reduction in order to maintain satisfactory therapeutic hypoprothrombinemia.

Concurrent administration of oxyphenbutazone and androgens may result in elevated serum levels of oxyphenbutazone.

In diabetic patients, the metabolic effects of androgens may decrease blood glucose and, therefore, insulin requirements.

Drug/Laboratory test interferences

Androgens may decrease levels of thyroxine-binding globulin, resulting in decreased total T4 serum levels and increased resin uptake of T3 and T4. Free thyroid hormone levels remain unchanged, however, and there is no clinical evidence of thyroid dysfunction.

What Are Side Effects of Halotestin?

Common side effects of Halotestin (fluoxymesterone) include:

• nausea
• vomiting
• headache
• skin color changes
• increased/decreased sexual interest
• oily skin
• hair loss, and
• acne

Tell your doctor if you experience these unlikely but serious side effects: anxiety, depression, increased anger. Men should tell their doctor if they experience side effects including difficulty urinating, frequent or prolonged erections, or breast swelling/tenderness. Women should tell their doctor if they experience side effects including deepening voice, unusual hair growth, or irregular menstrual periods.

Seek medical care or call 911 at once if you have the following serious side effects:

• Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
• Serious heart symptoms such as fast, irregular, or pounding heartbeats; fluttering in your chest; shortness of breath; and sudden dizziness, lightheadedness, or passing out;
• Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors.

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.