Generic Name

Supprelin LA

Mechanism

• GnRH receptor agonist: binds to pituitary GnRH receptors, producing an initial surge in luteinizing hormone (LH) and follicle‑stimulating hormone (FSH).
• Desensitization: continuous stimulation leads to down‑regulation of receptors, resulting in a sustained decrease in LH/FSH secretion.
• Hormonal suppression: ↓ testosterone in males; ↓ estrogen in females, thereby reducing tumor growth or symptomatic estrogen production.

Pharmacokinetics

• Formulation: 3.75 mg or 7.5 mg of leuprolide acetate in a biodegradable polymer for extended release.
• Absorption: subcutaneous (SC) injection; peak serum levels ~24 h post‑injection.
• Distribution: ~15 % protein binding; crosses blood‑brain barrier minimally.
• Metabolism: largely unchanged; metabolized via hydrolysis in plasma.
• Elimination: renal (≈20 %) and hepatic (≈80 %) routes; terminal half‑life 3–4 days; depot release provides effective coverage for 3–6 months.
• Drug interactions: minimal; may potentiate effects of medications causing QT prolongation.

Indications

• Prostate cancer: metastatic or locally advanced hormone‑sensitive disease.
• Gynecologic disorders: endometriosis, uterine fibroids, adenomyosis.
• Endocrinology: precocious puberty, hirsutism (when combined with anti‑androgens).
• Transgender hormone therapy: masculinizing or feminizing protocols in selected cases.

Contraindications

• Hypersensitivity to leuprolide or excipients.
• Pregnancy: contraindicated; risk of fetal testosterone deficiency.
• Severe hepatic impairment: avoid use.
• Known hypersensitivity to GnRH agonists.
• Severe cardiovascular disease: risk of exacerbated ischemia.
• Bone metabolic disorders: baseline bone density testing required.

Dosing

• Injection technique: Rotate sites, use 1–2 cm depth; observe for pain, erythema, or hematoma.
• Premedication: Not routinely required; antihistamine may be used if history of injection reaction.

Adverse Effects

Monitoring

• Seizures: rare but reported; monitor neurologic status.
• Cardiac arrhythmias: consider baseline ECG if at risk.
• Bone fractures: high risk in elderly or long‑term use.

Clinical Pearls

• “Hot‑flash first aid”: co‑prescribe low‑dose NSAIDs or gabapentin; avoid hot‑flash‑inducing triggers (caffeine, alcohol).
• Bone health: co‑treat with bisphosphonates or denosumab if baseline T‑score ≤ −1.5 or if >5 years of therapy.
• Weight‑based dosing: 3.75 mg SC for patients < 80 kg; 7.5 mg for heavier patients—skipping the weight adjustment can lead to suboptimal suppression.
• Avoid “bolus” injection: use the slow‑release polymer; a single 3.75 mg SC dose yields ~90 % suppression for 3 months.
• Transgender protocol: use 7.5 mg SC every 3 months; monitor testosterone and estrogen levels; consider adding aromatase inhibitor if estradiol remains high.
• Injection site rotation: SC injections into the abdomen, thigh, or buttock; avoid the same site every visit to minimize scar tissue and local pain.
• Pregnancy test: mandatory before every cycle; patient education on contraception during therapy.

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• Key Takeaway: Supprelin LA provides reliable, long‑acting hormonal suppression with a favorable safety profile when properly monitored. Use dose‑adjusted SC injections, proactive bone protection, and patient education to maximize efficacy and minimize adverse events.