Zutam

Tamoxifen, a nonsteroidal antiestrogen, is a triphenylethylene derivative with both estrogen antagonist on breast tissue and in the CNS and as an estrogen agonist on endometrium, bone and lipids.

Tamoxifen and at least several of its metabolites compete with estradiol for binding to cytyplasmic estrogen receptors in tissues such as breast, uterus, vagina, anterior pituitary, and tumors containing high concentrations of estrogen receptors.

Tamoxifen is used alone as an adjunct to surgery and radiation therapy for the treatment of breast cancer in women with negative axilliary lymph nodes and in postmenopausal women with positive axillary lymph nodes.

Adjuvant Tamoxifen therapy reduces the occurrence of contralateral breast cancer in premenopausal or postmenopausal women with breast cancer.

Tamoxifen has been used to stimulate ovulation in appropriately selected anovulatory women desiring pregnancy, especially in those with oligomenorrhoea or amenorrhoea who were previously receiving oral contraceptives.

Limited data also suggest that an occasional patient with a malignant carcinoid tumour and carcinoid syndrome may have a beneficial response to Tamoxifen.

Tamoxifen therapy prolongs disease-free survival and reduces mortality in premenopausal, postmenopausal, node-positive, and node-negative patients.

Positive objective responses are more frequent in patients with estrogen receptor-positive tumors.

The role of tamoxifen in combination with chemotherapy needs to be further clarified with respect to the optimal regimen, sequential vs concomitant therapy, and appropriate patient selection.

While the optimum duration of tamoxifen therapy has not yet been established, tamoxifen remains a major therapeutic agent in the medical management of breast cancer.

Pregnancy

Women who are pregnant or who plan to become pregnant should not use Tamoxifen to reduce the risk of breast cancer.

Nursing Mother

It is not known if Tamoxifen is distributed into milk.

Because of the potential for serious adverse reactions to Tamoxifen in nursing infants, a decision should be made whether to discontinue nursing or the drug, taking into account the importance of the drug to the woman.

Pediatric Use

Safety and efficacy of Tamoxifen in pediatric patients have not been established.

Tamoxifen is administered orally.

Breast Cancer

Adjuvant Therapy

When Tamoxifen is used alone as an adjunct to surgery and radiation therapy in the treatment of breast cancer, the usual dosage of the drug is 20-40 mg daily.

Dosages exceeding 20 mg daily should be given in divided doses (morning and evening).

There is no evidence that higher dosages are necessary.

The optimum duration of adjuvant Tamoxifen therapy has not been established, but therapy for about 5 years is more effective than shorter courses of therapy.

Longer therapy (i.e., beyond 5 years) with Tamoxifen is not recommended for routine use in women with node-negative breast cancer.

When Tamoxifen is use in combination with chemotherapy as an adjunct to surgery in the treatment of breast cancer in postmenopausal women or in women 50 years of age or older who have positive axillary lymph nodes, the usual dosage of the drug is 10 mg twice daily.

The optimum duration of adjuvant Tamoxifen therapy has not been established.

Metastatic Breast Cancer

For the treatment of metastatic breast cancer in women, the usual dosage of Tamoxifen is 20-40 mg daily.

Dosages exceeding 20 mg daily should be given in divided doses (morning and evening).

Because there does not appear to be any significant difference in response rates with the two dosages, most clinicians believe that 20 mg daily usually should be used initially.

If an objective response to the drug occurs, it usually is evident within 4-10 weeks; however, several months of therapy may be required before an objective response occurs in patients with bone metastases.

Reduction In The Incidence Of Breast Cancer In Women At High Risk

For reduction in the incidence of breast cancer in women at high risk, the recommended dosage of Tamoxifen is 20 mg daily.

Because of negative findings and a lack of additional benefit associated with more prolonged therapy with the drug as an adjuvant in the treatment of breast cancer, a 5-year duration of Tamoxifen therapy currently is being recommended for the prevention of breast cancer in women at high risk of the disease.

Male Breast Cancer

For the treatment of advanced (metastatic) breast cancer in men, the usual dosage of Tamoxifen is 20-40 mg daily.

Dosages exceeding 20 mg daily should be given in divided doses (morning and evening).

When Tamoxifen alone or in combination with radiation therapy was used as an adjunct to surgery in the treatment of breast cancer in men, a Tamoxifen dosage of 20 mg daily was used, usually for 1-2 years.

The optimum duration of adjuvant Tamoxifen therapy has not been established; however, since adjuvant therapy of about 5 years appears to be more effective than shorter courses of therapy in women with breast cancer, some clinicians suggest the same prolonged Tamoxifen course for male patients.

Other Uses

To stimulate ovulation, 5-40 mg of Tamoxifen has been administered twice daily for 4 days.