Nasal Pituitary desensitisation before ovulation induction with gonadotrophins
Adult: As 150 mcg/spray preparation: 1 spray in 1 nostril 4 times daily, starting either in the early follicular phase (day 1) or in the mid-luteal phase (day 21, given that the existence of early pregnancy is excluded). Therapy should be continued until pituitary downregulation occurs, which normally takes 2-3 weeks. In some cases, 300 mcg 4 times daily may be given as necessary. Treatment guidelines may vary among countries or individual products. Refer to product-specific recommendations.
Nasal Endometriosis
Adult: As 150 mcg/spray preparation: 1 spray into each nostril tid (morning, mid-day and evening). Usual treatment duration: 6 months. Treatment guidelines may vary among countries or individual products. Refer to product-specific recommendations.
Adult: Maintenance: As 100 mcg/spray preparation: 1 spray into each nostril 6 times daily usually before and after each meal, starting on day 8 (after the 7-day subcutaneous administration). Treatment guidelines may vary among countries or individual products. Refer to product-specific recommendations.
Subcutaneous Pituitary desensitisation before ovulation induction with gonadotrophins
Adult: Suprecur 200-500 mcg as a single dose daily; a dose of 500 mcg bid may be given as necessary. Suprefact 600 mcg in 3 divided doses daily. Therapy starts either in the early follicular phase (day 1) or in the mid-luteal phase (day 21, given that the existence of early pregnancy is excluded) and continued until pituitary down-regulation occurs, which normally takes 1-3 weeks. Treatment guidelines may vary among countries or individual products. Refer to product-specific recommendations.
Adult: 500 mcg 8 hourly for 7 days. Maintenance: Shift to intranasal route on day 8. Treatment guidelines may vary among countries or individual products. Refer to product-specific recommendations.
Subcutaneous Endometriosis
Adult: 200 mcg daily, starting on the 1st or 2nd day of menstruation; may be increased to 500 mcg as necessary, according to response. Usual treatment duration: 6-9 months. Treatment guidelines may vary among countries or individual products. Refer to product-specific recommendations.
Contraindications
Undiagnosed vaginal bleeding (when indicated for endometriosis or pituitary desensitisation); tumours that are insensitive to hormone manipulation or after surgical removal of testes (when indicated for prostatic carcinoma). Pregnancy and lactation.
Special Precautions
Patient with polycystic ovarian syndrome, depression, hypertension, diabetes, history of or risk factors for QT prolongation, risk factors for osteoporosis. Not indicated for use in post-menopausal women.
Adverse Reactions
Significant: Depression or exacerbation of existing depression, prolonged QT interval, decreased bone density, anaemia, hypogonadism, pituitary adenomas, ovarian cyst, hypersensitivity reactions (e.g. rash, redness, itch, allergic asthma with dyspnoea, anaphylaxis; disease flare, neurological sequelae, thrombosis, CV disease, impaired micturition, hydronephrosis, lymphostasis, bone pain (when indicated for prostatic carcinoma). Blood and lymphatic system disorders: Rarely, leucopenia, thrombocytopenia. Cardiac disorders: Palpitations. Ear and labyrinth disorders: Tinnitus, hearing disorders. Eye disorders: Impaired vision, dry eyes, feeling of pressure behind the eyes. Gastrointestinal disorders: Constipation or diarrhoea, nausea, vomiting, lower abdominal pain, increased thirst. General disorders and administration site conditions: Tiredness, local injection site reactions. Investigations: Increased or decreased weight, increased serum liver enzyme and bilirubin levels. Metabolism and nutrition disorders: Appetite changes. Musculoskeletal and connective tissue disorders: Musculoskeletal pain or discomfort. Nervous system disorders: Dizziness, drowsiness, headache, paraesthesia. Psychiatric disorders: Anxiety, emotional instability, mood changes, nervousness, disturbances in concentration, memory or sleep. Reproductive system and breast disorders: Menopausal-like symptoms (e.g. hot flushes, increased sweating, dry vagina, dyspareunia and loss of libido), vaginal discharge, breast tenderness, increased or decreased breast size, withdrawal or breakthrough bleeding; menstruation-like bleeding (nasal). Skin and subcutaneous tissue disorders: Acne, dry skin, increased or decreased scalp or body hair, splitting nails. Vascular disorders: Oedema of the face or extremities, hot flushes.
Patient Counseling Information
This drug may cause dizziness, if affected, do not drive or operate machinery.
Monitoring Parameters
Pituitary desensitisation: Perform pregnancy test prior to initiation of treatment. Prostate cancer: Serum testosterone levels, prostate-specific antigen, prostatic acid phosphatase, bone scan, signs/symptoms of obstructive uropathy, digital rectal exam, ECG (in patients at risk for QT prolongation), serum electrolytes. Endometriosis: Serum estradiol levels. Assess patient’s CV risk and for signs or symptoms of depression.
Overdosage
Symptoms: Asthenia, abdominal pain, dizziness, headache, nausea, nervousness, hot flushes, mastodynia, oedema of the lower extremities, local inj site reactions (e.g. pain, haemorrhage, induration). Management: Symptomatic and supportive treatment.
Drug Interactions
May reduce the effect of antidiabetic agents. Increased risk of QT prolongation with class IA (e.g. quinidine, disopyramide) or class III (e.g. amiodarone, sotalol,) antiarrhythmic agents, methadone, moxifloxacin, antipsychotics. Combined use with gonadotropins may increase the risk for ovarian hyperstimulation syndrome (OHSS) than the use of gonadotropins alone.
Lab Interference
Interferes with pituitary gonadotropic and gonadal function tests.
Action
Description: Mechanism of Action: Buserelin is a synthetic peptide gonadorelin analogue. Following an initial rise in the pituitary gonadotropins luteinising hormone and follicle-stimulating hormone, continued administration leads to down-regulation of the hypothalamic-pituitary-gonadal axis resulting in paradoxical reduction in sex hormone secretion. Onset: Mean time until testosterone reached castrate levels: 10 days (3-month depot implant). Pharmacokinetics: Absorption: Time to peak plasma concentration: Approx 1 hour. Nasal: Absorbed from the nasal mucus membranes. Bioavailability: 1-3% (intranasal); 70% (non-depot). Time to peak plasma concentration: <1 day (3-month depot). Distribution: Accumulates in the kidneys, liver and anterior pituitary lobe. Enters breast milk (small amounts). Plasma protein binding: Approx 15% (SC). Metabolism: Metabolised by pyrogutamyl peptidase, chymotrypsin-like endopeptidases and membrane-located enzymes in the liver, kidneys and pituitary gland, respectively. Excretion: Via urine (approx 50% as unchanged drug); faeces. Elimination half-life: 50-80 minutes (IV); 80-120 minutes (SC); 1-2 hours (nasal).
Chemical Structure
Buserelin_01 Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 50225, Buserelin. https://pubchem.ncbi.nlm.nih.gov/compound/Buserelin. Accessed Jan. 26, 2021.
Storage
Inj: Store below 25°C. Protect from light. Nasal spray: Store below 25°C or between 2-25°C. Do not freeze. Storage recommendations may vary among individual products. Refer to specific product guidelines.
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