This monograph describes a medication approved for use in Canada by the Therapeutic Products Directorate, a division of Health Canada’s Health Products and Food Branch. The medication is not approved by the United States Food and Drug Administration; however, a similar formulation carrying a different generic or brand name might be available in the US.
luteinizing hormone-releasing hormone (LHRH) analogues
- Subcutaneous injection– Initial and maintenance palliative treatment of advanced hormone-dependent prostate cancer (usually given with an anti-androgen).
- Nasal solution– Maintenance palliative treatment of advanced hormone-dependent prostate cancer (usually given with an anti-androgen).
- Nasal solution– Non-surgical treatment of endometriosis (course of treatment 6–9 mo).
Acts as a synthetic analog of endogenous gonadotropin-releasing hormone (GnRH/LHRH). Chronic use results in inhibited secretion of gonadotropin release and gonadal steroid production. The overall effect is due to down-regulation of pituitary LHRH receptors. In males, testosterone synthesis and release is decreased. In females, secretion of estrogen in decreased.
- Decreased spread of advanced prostate cancer.
- Decreased sequelae of endometriosis (pain, dysmenorrhea).
Absorption: Subcut– 70%; intranasal– 1–3%; implant– drug is slowly absorbed over 2–3 mo.
Distribution: Accumulates in liver, kidneys and anterior pituitary lobe; enters breast milk in small amounts.
Metabolism and Excretion: Metabolized in liver, kidneys and by enzymes on membranes in the pituitary gland.
Half-life: Subcut– 80 min; intranasal– 1–2 hr; implant– 20–30 days.
|prostate cancer †||7 days||4 mo||until discontinuation|
|endometriosis ‡(intranasal)||unknown||unknown||duration of treatment|
- Non-hormonal-dependent prostate cancer or previous orchiectomy;
- Females with undiagnosed vaginal bleeding;
- OB: Pregnancy (avoid use);
- Lactation: Avoid breast feeding (small amounts enter breast milk; injection contains benzyl alcohol).
Use Cautiously in:
- Prostate cancer with urinary tract obstruction or spinal lesions;
- Pedi: Safety and effectiveness not established (injection contains benzyl alcohol).
Adverse Reactions/Side Effects
CNS: depression, dizziness
Endo: glucose intolerance
Local: injection site reactions
MS: osteoporosis (long-term use)
Misc: transient exacerbation of metastatic prostate cancer or endometriosis
CNS: headache (nasal solution)
EENT: nasal irritation (nasal spray)
GU: ↓ libido, impotence
Derm: hot flushes
Endo: gynecomastia, testosterone flair
MS: bone pain
CNS: headache, weakness, insomnia
GI: constipation, gastrointestinal disorders, nausea
GU: ↓ libido, vaginal dryness, menorrhagia
Derm: hot flushes, acne
Endo: supression of ovulation
MS: back pain
* CAPITALS indicate life-threatening.
Underline indicate most frequent.
Risk of serious arrhythmias may be ↑ by concurrent amiodarone, disopyramide, dofetilide, flecainide ibutilide, propafenone quinidine, sotalol, antipsychotics (including chlorpromazine) antidepressants (including amitrypline and nortriptyline ), opioids (including methadone ), macrolide anti-infectives (including azithromycin, erythromycin and clarithromycin ), fluoroquinolones (including moxifloxacin ), azole antifungals, 5-HT3 antagonists (including ondansetron ), beta-2 receptor agonists (including salbutamol ), pentamidine, and quinine.
SC (Adults): Initial treatment– 500 mcg every 8 hr for 7 days, Maintenance treatment– 200 mcg daily.
Intranasal (Adults): Maintenance treatment– 400 mcg (200 mcg in each nostril) 3 times daily.
Subcut implant: (Adults): 6.3 mg every 2 mo or 9.45 mg every 3 mo.
Intranasal (Adults): 400 mcg (200 mcg in each nostril) 3 times daily. Treatment is usually continued for 6 mo; not to exceed 9 mo.
Solution for subcutaneous injection (contains benzyl alcohol): 1000 mcg/mL
Intranasal Solution: 1000 mcg/mL (delivers 100 mcg per actuation)
Subcutaneous implant (depot): 6.3 mg (2–mo implant), 9.45 mg (3–mo implant)
- Cancer: Monitor patients with vertebral metastases for increased back pain and decreased sensory/motor function.
- Monitor intake and output ratios and assess for bladder distention in patients with urinary tract obstruction during initiation of therapy.
- Endometriosis: Assess for signs and symptoms of endometriosis before and periodically during therapy. Amenorrhea usually occurs within 8 wk of initial administration and menses usually resume 8 wk after completion.
Lab Test Considerations:
Monitor serum testosterone levels every 3 mo during treatment with male patients. When treatment begins, testosterone levels can temporarily markedly ↑ and patients may need another medication to ↓ levels.
- Monitor blood glucose in patients with diabetes frequently; may affect blood glucose levels.
- Verify negative pregnancy test before starting therapy for women.
- Sexual dysfunction
- Disturbed body image
- SC Only use syringes that come with kit for accurate dose. Inject into fatty tissue of abdomen, arm, or leg 3 times/day for 7 days; then daily during maintenance.
- Intranasal When used as maintenance, begin nasal spray in each nostril 3 times daily. If patient also receives decongestant nasal spray, wait 30 min to give buserelin spray before or after the decongestant.
Implant is inserted in subcut tissue of upper abdominal wall every 28 days. Local anesthesia may be used before injection.
- If the implant needs to be removed for any reason, it can be located by ultrasound.
- Intranasal One spray in each nostril 3 times daily for 6–9 mo.
- Inform male patients that they may experience breast swelling and tenderness, decreased libido, hot flashes and sweats, impotence and weight gain. Notify health care professional if these symptoms occur.
- Inform female patients that they may experience decreased libido, constipation, painful sexual intercourse, menopausal symptoms, changes in hair growth. Notify health care professional if these symptoms occur.
- Caution both male and female patients to use contraception while taking this drug. Advise female patient to inform health care professional if pregnancy is suspected. Buserelin can be harmful to a fetus.
- SC Instruct patient in proper technique for self-injection, care and disposal of equipment. Use only syringes included in kit. Instruct patients that syringes may only be used once, and then discarded.
- Intranasal Instruct patient on proper nasal spray technique. Prime pump before use.
- Advise patients that the nasal spray can cause nose bleeds, and may change smell and taste senses.
- Decrease in the spread of prostate cancer.
- Decrease in lesions and pain in endometriosis.
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