Drug information of Buserelin

Buserelin

Drug group:

Buserelin is a synthetic peptide analog of the luteinizing hormone-releasing hormone (LHRH) agonist, which stimulates the pituitary gland's gonadotrophin-releasing hormone receptor (GnRHR).

Mechanism of effect

Buserelin stimulates the pituitary gland's gonadotrophin-releasing hormone receptor (GnRHR). Buserelin desensitizes the GnRH receptor, reducing the amount of gonadotropin. In males, this results in a reduction in the synthesis and release of testosterone.
In females, estrogen secretion is inhibited. While initially, there is a rise in FSH and LH levels, chronic administration of Buserelin results in a sustained suppression of these hormones.

Pharmacodynamic

The effects of buserelin on FSH and LH release are 20 to 170 times greater than those of LHRH.
Buserelin also has a longer duration of action than natural LHRH. Investigations in healthy adult males and females have demonstrated that the increase in plasma LH and FSH levels persist for at least 7 hours and that a return to basal values requires about 24 hours.
Clinical inhibition of gonadotropin release, and subsequent reduction of serum testosterone or estradiol to castration level, was found when large pharmacologic doses (50-500 mcg SC/day or 300-1200 mcg IN/day) were administered for periods greater than 1 to 3 months. Chronic administration of such doses of buserelin results in sustained inhibition of gonadotropin production, suppression of ovarian and testicular steroidogenesis and, ultimately, reduced circulating levels of gonadotropin and gonadal steroids. These effects form the basis for buserelin use in patients with hormone-dependent metastatic carcinoma of the prostate gland as well as in patients with endometriosis.

Pharmacokinetics

Buserelin is water soluble and readily absorbed after subcutaneous injection (70% bioavailable). When administered correctly via the nasal route, it may be absorbed in the nasal mucosa to achieve sufficient plasma levels.
Buserelin circulates in serum predominantly in intact active form. Preferred accumulation is preferentially in the liver and kidneys as well as in the anterior pituitary lobe, the biological target organ. Protein binding is 15%. It is metabolized and subsequently inactivated by peptidase (pyroglutamyl peptidase and chymotrypsin-like endopeptidase) in the liver and kidneys as well as in the gastrointestinal tract.
In the pituitary gland, it is inactivated by membrane-located enzymes. Buserelin and its inactive metabolites are excreted via the renal and biliary routes. In man it is excreted in urine at 50% in its intact form. The elimination half-life is approximately 50 to 80 minutes following intravenous administration, 80 minutes after subcutaneous administration and approximately 1 to 2 hours after intranasal administration.

Dosage

Prostate cancer, advanced
Initial: 500 mcg every 8 hoursSubQ for 7 days. Maintenance: 200 mcg once daily.
Note: Administration of an antiandrogen agent beginning 7 days prior to initiation of buserelin therapy and continuing for ~5 weeks with buserelin therapy is recommended in patients with prostate cancer.
Endometriosis
200 mcg buserelin by S.C. injection increasing to 500 mcg daily, depending upon symptomatic response. Treatment should be started on the first or second day of the menstrual period in order to exclude, as far as possible, the existence of pregnancy.
Treatment is usually given for 6 months and should not exceed 9 months. The inception of buserelin treatment may cause ovulation and contraceptive measures should be in place.
Adjunctive use in Ovulation Induction
600 mcg buserelin by S.C. injection as a divided dose 3 times daily. Treatment should start in the early follicular phase (day 1) or, provided the existence of any early pregnancy has been excluded, in the midluteal phase (day 21). It should continue at least until down-regulation is achieved (ie. serum oestradiol < 50 ng/l and serum progesterone < 1 mcg/l).
This will usually take about 2-3 weeks with nasal spray administration, and is less with parenteral use. When down-regulation is achieved stimulation with gonadotrophin is commenced while the dosage of buserelin is maintained.
At the appropriate stage of follicular development gonadotrophin and buserelin are stopped and human chorionic gonadotropin (hCG) is given to induce ovulation. Treatment monitoring, oocyte transfer and fertilization techniques are performed according to the normal practice of the individual clinic. Luteal support with hCG or progesterone should be given as appropriate.

Drug contraindications

Pregnancy , Lactation , hypersensitivity to this drug , patients with undiagnosed abnormal vaginal bleedin

Side effects

nausea , Headache , constipation , flushing , vertigo , Depression , Diarrhea , asthenia , Hypertension , palpitations , acne , Rhinitis , edema , anxiety , Pain , Cutaneous Reaction , flatulence , decreased libido , mouth ulcers , increased appetite , Restlessness , vaginitis , trouble in sleeping , Infection , Back pain , Gynecomastia , rhinitis , mastalgia

Alerts

Buserelin is water soluble and readily absorbed after subcutaneous injection (70% bioavailable). When administered correctly via the nasal route, it may be absorbed in the nasal mucosa to achieve sufficient plasma levels.
Buserelin circulates in serum predominantly in intact active form. Preferred accumulation is preferentially in the liver and kidneys as well as in the anterior pituitary lobe, the biological target organ. Protein binding is 15%. It is metabolized and subsequently inactivated by peptidase (pyroglutamyl peptidase and chymotrypsin-like endopeptidase) in the liver and kidneys as well as in the gastrointestinal tract.
In the pituitary gland, it is inactivated by membrane-located enzymes. Buserelin and its inactive metabolites are excreted via the renal and biliary routes. In man it is excreted in urine at 50% in its intact form. The elimination half-life is approximately 50 to 80 minutes following intravenous administration, 80 minutes after subcutaneous administration and approximately 1 to 2 hours after intranasal administration.

Points of recommendation

To make sure this medicine is safe for you, tell your doctor if you have:
• If you have an allergy to this medicine or any other part of it.
• If you are allergic to any drugs like this one, any other drugs, foods, or other substances. Tell your doctor about the allergy and what signs you had, like rash; hives; itching; shortness of breath; wheezing; cough; swelling of face, lips, tongue, or throat; or any other signs.
• If you are pregnant or breast-feeding.
• If you have low moods or are depressed.
• If you have high blood pressure (hypertension).
• If you have sugar diabetes (diabetes mellitus).
• If you have a bone disease such as osteoporosis.
• If you have polycystic ovary disease.
• If you have had any bleeding from your vagina that you do not think is related to your periods.
• If you have a tumour.
• If you are taking or using any other medicines. This includes any medicines you are taking which are available to buy without a prescription, such as herbal and complementary medicines.
• If you miss a dose of buserelin , take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Pregnancy level

X

Related drugs

Histrelin , Goserelin


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