Buserelin

Buserelin, sold under the brand name Suprefact among others, is a medication which is used primarily in the treatment of prostate cancer and endometriosis. In addition, buserelin is used in veterinary medicine.

Side effects of buserelin are related to sex hormone deprivation and include symptoms of low testosterone levels and low estrogen levels such as hot flashes, sexual dysfunction, vaginal atrophy, and osteoporosis.

Buserelin was first patented in 1974 and approved for medical use in 1985. It is not available in the United States, but is marketed widely elsewhere in the world, including in the United Kingdom, Canada, and many other countries. Buserelin is available as a generic medication.

Medical uses

Buserelin is approved for the treatment of hormone-responsive cancers including prostate cancer and premenopausal breast cancer, sex hormone-dependent uterine diseases including endometrial hyperplasia, endometriosis, and uterine fibroids, and in assisted reproduction for female infertility. It has also been assessed as a nasal spray for use as a hormonal contraceptive in women, with a 96% anovulation rate. If buserelin is used as a nasal spray, the dosage for prostate cancer is 800 μg sprayed into the nostrils three times per day (once every 8 hours, 2,400 μg/day total) for one week followed by 400 μg sprayed into the nostrils three times per day (once every 8 hours, 1,200 μg/day total) thereafter.

Available forms

Buserelin is available in the form of a 1 mg/mL solution for use as a nasal spray or subcutaneous injection once every 8 hours (three times per day) and as 6.3 mg and 9.45 mg implants for subcutaneous injection once every two and three months, respectively.

Contraindications

Contraindications of buserelin include the following: In accordance, GnRH analogues like buserelin can reduce testosterone levels by about 95% in men. The suppression of estradiol levels is 95% and progesterone levels are less than 1 ng/mL (normal range during the luteal phase approximately 10–20 ng/mL); the resulting levels are equivalent to those in postmenopausal women.

Buserelin has been found to suppress testosterone levels in men with prostate cancer from 426 ng/dL to 28 ng/dL (by 93.4%) with 200 μg by subcutaneous injection once per day and from 521 ng/dL to 53 ng/dL (by 89.8%) with 400 μg by nasal spray once every 8 hours (1,200 μg/day total). The difference in suppression may have been due to poor compliance. One such study found that testosterone levels in men with prostate cancer were suppressed during treatment with buserelin from 332 ng/dL to 215 ng/dL (28.9% lower than controls) with 200 μg by nasal spray twice a day (400 μg/day total), from 840 ng/dL to 182 ng/dL (71.4% lower than controls) with 500 μg by nasal spray twice a day (1,000 μg/day total), and from 598 ng/dL to 126 ng/dL (80.4% lower than controls) with 50 μg by subcutaneous injection once a day. Buserelin is marketed for medical use in both its free base (buserelin) and acetate salt (buserelin acetate) forms. Intranasal buserelin was the first GnRH agonist demonstrated to achieve medical castration in humans. This was initially observed via a marked decrease in circulating testosterone levels in a single patient in 1980. While under development by Hoechst AG, buserelin was also known as HOE-766. It is not available in the United States or Australia.

Research

The steroidal antiandrogen cyproterone acetate has been studied for blocking the testosterone flare at the start of buserelin therapy in men with prostate cancer. While cyproterone acetate for two weeks eliminates the biological and biochemical signs of the flare, no benefits on prostate cancer outcomes were observed.

References

External links

Buserelin - AdisInsight