Suprefact Depot (Buserelin): Uses, Dosage & Side Effects
GnRH agonist implant for advanced prostate cancer and precocious puberty
Quick Facts About Suprefact Depot
Key Takeaways
- Suprefact Depot contains buserelin, a GnRH agonist that suppresses sex hormone production after an initial brief stimulation phase.
- In prostate cancer, testosterone is reduced to castrate levels within 3–4 weeks, slowing hormone-dependent tumour growth.
- Anti-androgen co-therapy is essential during the first 3–4 weeks to prevent tumour flare symptoms.
- Long-term use can reduce bone mineral density; regular bone density monitoring is recommended.
- The implant is administered subcutaneously into the abdominal wall every two months by a healthcare professional.
What Is Suprefact Depot and What Is It Used For?
Suprefact Depot belongs to a group of medicines known as luteinising hormone-releasing hormone (LHRH) analogues, also called GnRH agonists. Buserelin closely mimics the structure of the naturally occurring GnRH hormone produced by the hypothalamus in the brain. However, unlike the body's natural pulsatile release of GnRH, the continuous exposure from the implant ultimately leads to a paradoxical shutdown of the hormonal cascade that controls sex hormone production.
Prostate Cancer
In men with advanced prostate cancer, Suprefact Depot works by suppressing the production of testosterone, a male sex hormone. While testosterone has essential physiological roles in the body, it can also stimulate the growth of hormone-sensitive prostate tumours. By reducing testosterone to very low levels (comparable to surgical castration), Suprefact Depot effectively slows or halts tumour progression.
After starting treatment with Suprefact Depot, there is an initial brief rise in testosterone levels during the first one to two weeks. This is followed by a progressive decline, with testosterone reaching castrate levels (below 50 ng/dL) within approximately 3 to 4 weeks of treatment. This hormonal suppression is maintained for as long as the treatment continues, with new implants administered every two months.
Androgen deprivation therapy (ADT) with GnRH agonists like buserelin is a cornerstone of treatment for advanced prostate cancer, as endorsed by international guidelines from the European Association of Urology (EAU), the National Comprehensive Cancer Network (NCCN), and the American Urological Association (AUA). It may be used as monotherapy or in combination with other treatments such as radiotherapy or chemotherapy.
Central Precocious Puberty
In children with central precocious puberty (CPP), the body begins sexual maturation too early. In girls, this may manifest as breast development and menstruation before the age of 8, while in boys it can present as testicular enlargement and other secondary sexual characteristics before the age of 9. CPP is caused by premature activation of the hypothalamic-pituitary-gonadal axis.
Suprefact Depot suppresses the premature release of sex hormones in these children. In girls, breast development ceases or regresses, and after an initial withdrawal bleed, menstrual periods stop as oestrogen levels decline. In boys, testicular growth halts and other pubertal signs stabilise. Treatment typically continues for 3 to 4 years, allowing the child to reach an appropriate age for natural puberty to resume after discontinuation.
The Endocrine Society and the European Society for Paediatric Endocrinology recommend GnRH agonists as the standard treatment for CPP, citing their established safety profile and effectiveness in preserving adult height potential and allowing age-appropriate psychosocial development.
What Should You Know Before Taking Suprefact Depot?
Contraindications
You must not use Suprefact Depot if you have a known allergy (hypersensitivity) to buserelin, to any other GnRH analogues (such as leuprolide, goserelin, or triptorelin), or to any of the excipients in the formulation. Allergic reactions can range from mild skin reactions to severe anaphylaxis, and any prior reaction to a GnRH agonist should be reported to your doctor before considering Suprefact Depot.
The medication is contraindicated in women who are pregnant or breastfeeding, as GnRH agonists can cause harm to the developing foetus. A pregnancy test should be performed before initiating treatment in women of childbearing potential.
Warnings and Precautions
Before starting Suprefact Depot, discuss the following conditions with your healthcare provider:
- Prior orchiectomy: If your testicles have been surgically removed, Suprefact Depot will not provide additional hormonal benefit, as testosterone production has already been eliminated.
- Metastatic disease: If prostate cancer has spread, particularly to the spine, there is a risk of spinal cord compression during the initial tumour flare period. Close monitoring is essential.
- Cardiovascular disease: Patients with existing heart disease or risk factors for cardiovascular events (such as prior myocardial infarction) should be carefully monitored. GnRH agonist therapy has been associated with an increased cardiovascular risk.
- Cardiac arrhythmias: Suprefact Depot may increase the risk of QT prolongation. Patients with a history of arrhythmias or those taking QT-prolonging medications require ECG monitoring.
- Diabetes mellitus: Buserelin can affect glucose metabolism, potentially altering blood sugar control. Regular blood glucose monitoring is recommended, and diabetes medications may need adjustment.
- Hypertension: Blood pressure should be monitored regularly during treatment, as Suprefact Depot may influence blood pressure control.
- Depression: Patients with a history of depression should be monitored closely, as GnRH agonist therapy may trigger or worsen depressive episodes. Report any changes in mood to your doctor immediately.
At the start of prostate cancer treatment, Suprefact Depot can cause a temporary increase in testosterone levels, leading to a worsening of symptoms known as "tumour flare." This may manifest as increased bone pain, difficulty urinating, muscle weakness in the legs, fluid retention, or blood clots in the lungs. To prevent tumour flare, your doctor will typically prescribe an anti-androgen medication starting approximately 5 days before the first implant and continuing for the first 3–4 weeks of treatment.
Long-term treatment with GnRH agonists can decrease bone mineral density, leading to osteoporosis and an increased risk of fractures. Risk is higher in patients who smoke, consume excessive alcohol, have a family history of osteoporosis, or are taking corticosteroids or anti-epileptic medications. Your doctor should monitor bone density regularly and may prescribe calcium, vitamin D supplements, or bisphosphonates as preventive measures.
Pregnancy and Breastfeeding
Suprefact Depot is contraindicated during pregnancy and breastfeeding. GnRH agonists can disrupt normal hormonal balance critical for foetal development and may cause spontaneous abortion or foetal harm. Women of childbearing potential should use effective non-hormonal contraception during treatment and for a period after discontinuation, as advised by their doctor.
It is not known whether buserelin passes into breast milk. Given the potential for serious adverse effects in nursing infants, breastfeeding should be discontinued before initiating Suprefact Depot therapy.
Driving and Operating Machinery
Suprefact Depot may cause side effects such as dizziness, drowsiness, and visual disturbances that can impair your ability to drive or operate machinery safely. You should assess your own fitness to drive, taking into account the potential effects of the medication. If you experience any symptoms that affect your concentration or reaction time, refrain from driving or operating heavy machinery and discuss with your healthcare provider.
How Does Suprefact Depot Interact with Other Drugs?
Drug interactions can alter how Suprefact Depot works or increase your risk of serious side effects. It is essential to inform your healthcare provider about all medications you are currently taking, have recently taken, or plan to take, including prescription drugs, over-the-counter medicines, and herbal supplements.
Major Interactions
The following drug interactions are considered clinically significant and may require dose adjustments, close monitoring, or avoidance of concurrent use:
| Interacting Drug | Effect | Clinical Recommendation |
|---|---|---|
| Anti-arrhythmics (quinidine, procainamide, amiodarone, sotalol) | Additive QT prolongation risk; increased risk of potentially fatal cardiac arrhythmias (torsades de pointes) | ECG monitoring required; cardiologist review recommended before concurrent use |
| Methadone | Additive QT prolongation risk | ECG monitoring; use with caution; consider alternative pain management |
| Moxifloxacin (fluoroquinolone antibiotic) | Additive QT prolongation risk | Consider alternative antibiotics; if unavoidable, monitor ECG |
| Antipsychotics (e.g., haloperidol, quetiapine, ziprasidone) | Additive QT prolongation risk | Baseline and periodic ECG monitoring; risk-benefit assessment required |
Minor Interactions
| Interacting Drug | Effect | Clinical Recommendation |
|---|---|---|
| Antidiabetic medications (insulin, metformin, sulfonylureas) | Buserelin may impair glucose tolerance, reducing the effectiveness of diabetes treatment | Monitor blood glucose more frequently; adjust antidiabetic doses as needed |
| Anti-androgen drugs (bicalutamide, flutamide) | Intentional combination to prevent tumour flare; anti-androgens block the initial testosterone surge | Standard of care: start anti-androgen ~5 days before first Suprefact Depot dose; continue for 3–4 weeks |
| Corticosteroids | Concurrent use increases risk of osteoporosis | Monitor bone density; consider bone-protective agents |
This list is not exhaustive. Other medications not listed here may also interact with Suprefact Depot. Always inform your healthcare provider and pharmacist about all medicines you are taking to ensure safe and effective treatment.
What Is the Correct Dosage of Suprefact Depot?
Always use Suprefact Depot exactly as your doctor has prescribed. Do not change the dose or dosing schedule without medical advice. The implant is intended for long-term treatment and must be administered by a trained healthcare professional.
Adults (Prostate Cancer)
Standard Dose
1 pre-filled syringe (2 implants) administered subcutaneously into the abdominal wall every 2 months (every 8 weeks).
Each syringe delivers a total of 6.6 mg buserelin acetate (equivalent to 6.3 mg buserelin). A local anaesthetic may be applied before the injection to minimise discomfort. It is critical to maintain the two-month dosing interval consistently to ensure continuous testosterone suppression.
Suprefact Depot is designed for long-term treatment. Your doctor will determine the appropriate duration of therapy based on your cancer type, stage, and response to treatment. In many cases, ADT with GnRH agonists is continued indefinitely or until disease progression necessitates a change in treatment strategy.
Children (Precocious Puberty)
Paediatric Dose
1 pre-filled syringe (2 implants) administered subcutaneously into the abdominal wall every 2 months.
Treatment duration is typically 3 to 4 years, with regular assessment of pubertal development, growth velocity, and bone age by a paediatric endocrinologist. Treatment is discontinued when the child reaches an appropriate age for natural puberty to resume.
Elderly Patients
No dose adjustment is required for elderly patients. However, older adults may be at increased risk for cardiovascular events, osteoporosis, and metabolic changes during GnRH agonist therapy. More frequent monitoring of bone density, cardiovascular health, and metabolic parameters is recommended in this population.
Missed Dose
If a scheduled injection is missed, contact your healthcare provider as soon as possible to arrange an appointment. Delaying the injection can lead to a rise in testosterone levels, potentially allowing tumour progression. Do not attempt to administer the implant yourself. Your doctor will advise on the appropriate timing for the next injection based on how long ago the scheduled dose was missed.
Overdose
Overdose with Suprefact Depot is unlikely given that it is administered by healthcare professionals. However, if an overdose occurs, symptoms may include:
- Weakness and fatigue
- Anxiety and restlessness
- Dizziness and headache
- Nausea and abdominal pain
- Hot flushes
- Peripheral oedema (swelling of ankles and lower legs)
- Breast tenderness
- Injection site reactions
In the event of a suspected overdose, seek medical attention immediately. Treatment is supportive and symptomatic. In some cases, it may be necessary to surgically remove the implant.
What Are the Side Effects of Suprefact Depot?
Like all medicines, Suprefact Depot can cause side effects, although not everyone experiences them. The frequency of side effects is categorised using standard medical terminology. Many side effects are related to the intended hormonal suppression and may be managed with supportive care.
Contact your doctor or emergency services immediately if you experience symptoms such as skin rash, difficulty swallowing or breathing, or swelling of the lips, face, throat, or tongue. These may be signs of a serious allergic reaction. Inform medical staff that you have Suprefact Depot implants, as surgical removal may be necessary.
Common
May affect up to 1 in 10 patients
- Headache
- Hot flushes
- Injection site pain, redness, or swelling
- Erectile dysfunction (impotence)
- Testicular atrophy (shrinkage)
- Decreased libido (sexual desire)
- Mood changes and depression (with long-term use)
Uncommon
May affect up to 1 in 100 patients
- Elevated liver enzymes (seen in blood tests)
- Weight gain or weight loss
- Drowsiness, dizziness, and fatigue
- Constipation
- Peripheral oedema (fluid retention in ankles and calves)
- Hypersensitivity reactions (skin rash, redness, itching, urticaria)
- Gynaecomastia (non-painful breast enlargement)
- Mood changes and depression (with short-term use)
Rare
May affect up to 1 in 1,000 patients
- Changes in blood lipids and elevated bilirubin
- Palpitations (rapid or irregular heartbeat)
- Elevated blood pressure (in patients with pre-existing hypertension)
- Insomnia and sleep disturbances
- Memory or concentration difficulties
- Nausea, vomiting, and diarrhoea
- Changes in body or head hair growth
- Severe allergic reactions (difficulty breathing)
- Anxiety, emotional instability
Very Rare
May affect up to 1 in 10,000 patients
- Decreased blood cell counts (may cause abnormal blood tests or bruising)
- Visual disturbances (blurred vision, sensation of pressure behind the eyes)
- Tinnitus (ringing in the ears) and hearing disturbances
- Musculoskeletal discomfort and pain
- Increased thirst and appetite changes
- Decreased glucose tolerance (worsened diabetic control)
- Pituitary adenoma enlargement
- Transient tumour pain despite anti-androgen co-therapy
- Severe allergic reactions with anaphylactic shock
- General malaise
Changes in heart rhythm (QT prolongation) visible on an electrocardiogram (ECG) have been reported. This is particularly relevant for patients taking other QT-prolonging medications concurrently. Your doctor may recommend periodic ECG monitoring during treatment.
Bone density effects: GnRH agonists as a class can cause decreased bone mineral density, leading to osteoporosis and an increased risk of bone fractures. The risk of fractures increases with the duration of treatment. Your healthcare provider should assess your bone health before starting treatment and monitor it at regular intervals throughout therapy.
If you notice any side effects not listed here, or if any side effect becomes severe or persistent, contact your healthcare provider. Reporting suspected adverse reactions helps regulatory authorities monitor the benefit-risk profile of medicines.
How Should You Store Suprefact Depot?
Suprefact Depot does not require any special storage conditions. However, the following general guidelines apply to ensure the medication remains safe and effective:
- Keep out of reach of children: Store in a location that is inaccessible to children and pets.
- Check the expiry date: Do not use Suprefact Depot after the expiry date (EXP) printed on the carton. The expiry date refers to the last day of the stated month.
- Single use only: The pre-filled syringe is for single use only. The applicator should be used immediately after opening the packaging.
- Proper disposal: Do not dispose of medicines via household waste or wastewater. Return unused or expired medicines to your pharmacy. This protects the environment and prevents accidental exposure.
What Does Suprefact Depot Contain?
Active Substance
The active substance is buserelin. Each pre-filled syringe contains two rod-shaped implants providing a total dose of 6.6 mg buserelin acetate, which is equivalent to 6.3 mg buserelin. Buserelin acetate is a synthetic nonapeptide analogue of the naturally occurring gonadotropin-releasing hormone (GnRH), with significantly greater potency than the endogenous hormone.
Excipients
The other ingredient is poly(D,L-lactide-co-glycolide) with a molar ratio for lactide:glycolide of 75:25. This biodegradable polymer serves as the matrix for the implant, controlling the sustained release of buserelin over the two-month dosing interval. The polymer gradually breaks down in the body into lactic acid and glycolic acid, both of which are naturally metabolised and excreted.
Physical Description
Each package contains 1 pre-filled injection syringe. The syringe contains two cream-coloured, rod-shaped implants. The applicator includes an injection needle, a protective cap, a plunger rod, and a protective sleeve. The implants are visible through the viewing window on the applicator handle.
Frequently Asked Questions About Suprefact Depot
Suprefact Depot is used primarily for two indications: the treatment of advanced (metastatic) prostate cancer, where it suppresses testosterone production to slow tumour growth, and the treatment of central precocious puberty in children, where it halts premature sexual development by suppressing sex hormone release. The implant contains buserelin, a GnRH agonist that ultimately down-regulates the pituitary gland's production of gonadotropins.
Suprefact Depot is administered as a subcutaneous injection every two months (every 8 weeks). Each pre-filled syringe contains two rod-shaped implants that are injected into the abdominal wall by a healthcare professional. Maintaining the regular two-month interval is essential to ensure continuous hormone suppression. A local anaesthetic may be applied before the injection.
Tumour flare is a temporary worsening of symptoms that can occur during the first 3–4 weeks of treatment. It results from an initial rise in testosterone before the medication suppresses it. Symptoms may include increased bone pain, urinary difficulties, and muscle weakness. To prevent this, anti-androgen therapy (such as bicalutamide or flutamide) is started approximately 5 days before the first Suprefact Depot injection and continued for 3–4 weeks until testosterone levels reach castrate levels.
Yes, long-term use of GnRH agonists like Suprefact Depot can decrease bone mineral density, increasing the risk of osteoporosis and fractures. The risk is higher in patients who smoke, drink alcohol excessively, have a family history of osteoporosis, or take corticosteroids or anti-epileptic medications. Your doctor should monitor bone density regularly and may recommend calcium and vitamin D supplementation or bisphosphonate therapy as preventive measures.
The most common side effects (affecting up to 1 in 10 patients) include hot flushes, headache, injection site reactions (pain, redness, swelling), erectile dysfunction, testicular atrophy, decreased libido, and mood changes including depression with long-term use. Many of these are a direct consequence of testosterone suppression and may improve with supportive care. Contact your doctor if side effects become troublesome or persistent.
Both products contain buserelin as the active ingredient, but they differ significantly in formulation and how they are used. Suprefact Depot is a subcutaneous implant administered every two months by a healthcare professional, providing continuous drug release. The Suprefact nasal spray (0.15 mg/dose) requires multiple daily administrations by the patient. The depot formulation offers better treatment adherence since it eliminates the need for daily self-administration.
References
This article is based on the following evidence-based sources and international medical guidelines:
- European Medicines Agency (EMA). Buserelin – Summary of Product Characteristics (SmPC). Available at: www.ema.europa.eu.
- National Comprehensive Cancer Network (NCCN). Clinical Practice Guidelines in Oncology: Prostate Cancer, Version 4.2025. Available at: www.nccn.org.
- European Association of Urology (EAU). Guidelines on Prostate Cancer, 2024 Update. Available at: uroweb.org.
- Carel JC, Eugster EA, Rogol A, et al. Consensus statement on the use of gonadotropin-releasing hormone analogs in children. Pediatrics. 2009;123(4):e752–e762. doi:10.1542/peds.2008-1783.
- Heidenreich A, Bastian PJ, Bellmunt J, et al. EAU guidelines on prostate cancer. Part II: treatment of advanced, relapsing, and castration-resistant prostate cancer. European Urology. 2014;65(2):467–479.
- Keating NL, O’Malley AJ, Smith MR. Diabetes and cardiovascular disease during androgen deprivation therapy for prostate cancer. Journal of Clinical Oncology. 2006;24(27):4448–4456.
- Smith MR. Androgen deprivation therapy and risk for diabetes and cardiovascular disease in prostate cancer survivors. Current Urology Reports. 2008;9(3):197–202.
- World Health Organization (WHO). WHO Model List of Essential Medicines, 23rd Edition, 2023. Available at: www.who.int.
- British National Formulary (BNF). Buserelin monograph. Available at: bnf.nice.org.uk.
- Shahinian VB, Kuo YF, Freeman JL, Goodwin JS. Risk of fracture after androgen deprivation for prostate cancer. New England Journal of Medicine. 2005;352(2):154–164.
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