Information for Patients
The physician should be consulted regarding missed doses. Notify the physician if adverse reactions occur or become more pronounced.
Plasma calcium levels should be routinely determined in any patient receiving therapy for mammary cancer, particularly during periods of active remission of bony metastases. If hypercalcemia occurs, appropriate measures should be instituted.
When administered concurrently, testolactone may increase the effects of oral anticoagulants; monitor and adjust anticoagulant dosage accordingly.
Drug/Laboratory Test Interactions
Physiologic effects of testolactone may result in decreased estradiol concentrations with radioimmunoassays for estradiol, increased plasma calcium concentrations (see PRECAUTIONS, Laboratory Tests), and increased 24-hour urinary excretion of creatine and 17-ketosteroids.
Carcinogenesis, Mutagenesis, Impairment of Fertility
No long-term animal studies have been performed to evaluate carcinogenic potential or mutagenesis. Testolactone did not affect fertility in male or female rats.
Teratogenic Effects, Category C
In rats, testolactone has been shown to produce increased fetal mortality, increased abnormal fetal development, and increased mortality in growing pups when given at doses 5 to 15 times the recommended human dose. In rabbits, no teratologic effects were observed at doses 2.5 to 7.5 times the recommended human dose. There are no adequate and well controlled studies in pregnant women. Testolactone is intended for use only in postmenopausal women and should not be used during pregnancy.
It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, a decision should be made whether or not to discontinue nursing.
Safety and effectiveness in pediatric patients have not been established.
Insufficient data from clinical studies of TESLAC are available for patients 65 years of age and older to determine whether they respond differently than younger patients. Other reported clinical experience has not identified differences in responses between elderly and younger patients. In general, caution should be exercised when prescribing to elderly patients, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.
Testolactone and its metabolites appear to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.