Leuprolide (Lupron)
Leuprolide Acetate (Leuprorelin Acetate); 5-oxo-L-prolyl-L-histidyl-L-tryptophyl-L-seryl-L-tyrosyl-D-leucyl-L-leucyl-L-arginyl-N-ethyl-L-prolinamide acetate
FDA-approved synthetic GnRH agonist (brand: Lupron, Lupron Depot, Eligard, Vabrinty) used for advanced prostate cancer, endometriosis, uterine fibroids, and central precocious puberty, acting via pituitary desensitization to suppress sex hormones (Plosker & Brogden 1994, DOI 10.2165/00003495-199448060-00008; FDA labels; PMID 32738042).
Last updated: 2026-03-10
Safety Summary
Most adverse effects result from suppression of sex hormones rather than direct drug toxicity. Hot flashes are the dominant class effect: 56.7-73.3% in Vabrinty prostate cancer trials (Table 4, Vabrinty label), 35-71% of men and approximately 80% of women with endometriosis in the 1994 review (Plosker & Brogden 1994, DOI 10.2165/00003495-199448060-00008). In the Lupron Depot endometriosis label, headache, vaginitis, depression/emotional lability, nausea/vomiting, dizziness, and weight change are listed as common events. In men, impotence and decreased libido occur in virtually all sexually active patients (expected pharmacological consequences noted in Vabrinty label). Testicular atrophy reported in 5.0-7.2% across Vabrinty trials (Vabrinty label Table 4). Disease flare (symptom exacerbation from initial testosterone surge) can be serious in prostate cancer patients with bone metastases or urinary obstruction; anti-androgen cover recommended. Leuprolide 3.75mg controlled bleeding in 89% of fibroid patients but caused moderate-to-severe hot flashes in 40% vs 10-11% with ulipristal (PMID 22296076). Bone mineral density loss occurs with long-term use; partially reversible after shorter courses (6 months) but potentially sustained with longer administration. Add-back therapy with norethindrone helps preserve BMD (Plosker & Brogden 1994; Lupron Depot label). Injection-site reactions (sterile abscess in 1 child) are the most frequent pediatric tolerability issue (PMID 1403402). FDA FAERS data shows hot flush (9,525 reports), fatigue (5,088), injection site pain (4,854), asthenia (2,382), arthralgia (1,952), headache (1,929), weight increased (1,797) as top reported events. Vabrinty postmarketing: rare pituitary apoplexy (usually within 2 weeks of first dose), convulsions, interstitial lung disease, SJS/TEN, erythema multiforme (Vabrinty label section 6.2). ADT may increase cardiovascular risk; hyperglycemia, diabetes, and QT prolongation are labeled warnings (Vabrinty label sections 5.2-5.4). A 2026 RCT (N=100+50) showed probiotic L. reuteri NCU-37 significantly reduced leuprolide-induced perimenopausal symptoms in IVF patients (PMID 41399984).
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Who Should NOT Use This
All labels contraindicate use in patients with known hypersensitivity. Anaphylactic reactions to synthetic GnRH agonists reported in literature (Vabrinty label section 4; Lupron Depot label; Plosker & Brogden 1994).
May cause fetal harm or pregnancy loss. Major fetal abnormalities observed in animal studies. Contraindicated for gynecologic indications; labeled embryo-fetal toxicity warning for prostate cancer use (Vabrinty label section 5.8; Lupron Depot label).
Must evaluate cause before initiating therapy. Lupron Depot 3.75mg is contraindicated in women with undiagnosed abnormal uterine bleeding (Lupron Depot label).
Testosterone flare during first 1-2 weeks can worsen bone pain, neuropathy, hematuria, bladder outlet obstruction, ureteral obstruction, or spinal cord compression. At-risk patients require close monitoring and often anti-androgen cover. Consider GnRH antagonist (degarelix, relugolix) instead if high risk (Vabrinty label section 5.1; Plosker & Brogden 1994, DOI 10.2165/00003495-199448060-00008).
Long-term GnRH agonist therapy reduces bone mineral density. Monitor with DEXA. Consider calcium, vitamin D, bisphosphonate prophylaxis. Lupron Depot labeling limits endometriosis treatment duration and recommends caution in patients with major BMD risk factors (Lupron Depot label; Plosker & Brogden 1994).
Increased risk of myocardial infarction, sudden cardiac death, and stroke reported with GnRH agonists in men. Monitor for cardiovascular disease. Risk should be evaluated carefully along with cardiovascular risk factors (Vabrinty label section 5.3). Historically, leuprolide had fewer cardiovascular complications than diethylstilbestrol (Plosker & Brogden 1994).
GnRH agonists may lead to hyperglycemia, diabetes, hyperlipidemia, and metabolic syndrome. Monitor blood glucose and/or HbA1c periodically (Vabrinty label section 5.2).
Hormonal suppression may worsen mood disorders. Emotional lability reported in 16-45% of women with endometriosis. Depression, insomnia, and loss of libido listed as psychiatric adverse reactions (Plosker & Brogden 1994; Vabrinty label adverse reactions).
Survival benefit of AST + RT vs RT alone may not apply to men with moderate-severe comorbidity (adjusted HR 0.54, 95% CI 0.27-1.10, p=0.08 favoring RT alone in this subgroup; PMID 18212313). Post-hoc subgroup analysis.
Talk to Your Doctor
Before considering Leuprolide (Lupron), discuss it with your healthcare provider. Ask about potential interactions with your current medications, whether it is appropriate for your health conditions, and what monitoring may be needed.
Sources: [1-21]
Evidence Assessment
Tier 1 -- FDA-approved since 1985 across multiple indications (advanced prostate cancer, endometriosis, uterine fibroids, central precocious puberty). Multiple Phase 3 RCTs support efficacy, including: the Crawford et al. 603-patient NEJM RCT of leuprolide + flutamide vs leuprolide alone in metastatic prostate cancer (PMID 2503724); the Heyns et al. 284-patient active-comparator trial showing durable medical castration (PMID 12887472); the Klein et al. Phase 3 trial of 6-month SC depot for CPP in 64 children (PMID 32738042); the Donnez et al. 307-patient NEJM trial of ulipristal vs leuprolide for fibroids (PMID 22296076); the D'Amico et al. 206-patient JAMA RCT of AST + RT vs RT alone (PMID 15315996); and numerous endometriosis trials vs danazol and buserelin (Plosker & Brogden 1994). Over 100 clinical trials registered on ClinicalTrials.gov. Multiple FDA-approved formulations (Lupron, Lupron Depot, Eligard, Vabrinty, generics;). Decades of post-marketing surveillance with extensive FAERS reporting.
1Leuprorelin: A Review of its Pharmacology and Therapeutic Use in Prostatic Cancer, Endometriosis and Other Sex Hormone-Related Disorders
Plosker GL, Brogden RN - Drugs (1994) - comprehensive review - Review of all published clinical data through 1994
Comprehensive review covering pharmacodynamics, pharmacokinetics, and clinical efficacy across prostate cancer, endometriosis, precocious puberty, uterine fibroids, and IVF. Leuprolide comparable to orchiectomy and other GnRH analogs for prostate cancer. In endometriosis, comparable to danazol 800mg/day and buserelin 900 mcg/day. Bioavailability 94% SC, half-life approximately 3.6 hours.
Limitations: Review article; data through early 1994 only. No meta-analysis methodology. Predates newer depot products and current labeling.
2A controlled trial of leuprolide with and without flutamide in prostatic carcinomaPMID 2503724
Crawford ED, Eisenberger MA, McLeod DG, et al. - The New England Journal of Medicine (1989) - RCT (double-blind, randomized) - 603 men with disseminated, previously untreated stage D2 prostate cancer
All patients received leuprolide; randomized to flutamide vs placebo. Adding flutamide improved progression-free survival from 13.9 to 16.5 months (p=0.039) and median survival from 28.3 to 35.6 months (p=0.035). Greatest symptomatic improvement during first 12 weeks when leuprolide alone produces flare.
Limitations: Older metastatic-disease population. Benefit reflects combined androgen blockade rather than leuprolide monotherapy efficacy.
3Comparative efficacy of triptorelin pamoate and leuprolide acetate in men with advanced prostate cancerPMID 12887472
Heyns CF, Simonin MP, Grosgurin P, et al. - BJU International (2003) - RCT (active-comparator) - 284 men with advanced prostate cancer
Leuprolide 7.5mg IM every 28 days achieved castrate testosterone in 99.3% of men by day 29 and 97.1% by day 57. Durable maintenance rates through day 253 equivalent to triptorelin. Both treatments well tolerated.
Limitations: Active-comparator design without placebo; focused on biochemical castration endpoints rather than detailed long-term survival outcomes.
46-month androgen suppression plus radiation therapy vs radiation therapy alone for patients with clinically localized prostate cancer: a randomized controlled trialPMID 15315996
D'Amico AV et al. - JAMA (2004) - RCT - 206 patients
Patients randomized to 70 Gy 3D-CRT + 6 months AST had significantly higher survival (p=0.04), lower prostate cancer-specific mortality (p=0.02), and higher survival free of salvage AST (p=0.002). 5-year survival 88% (95% CI 80-95%) for RT+AST vs 78% (95% CI 68-88%) for RT alone.
Limitations: Single-institution trial. Median follow-up 4.52 years at initial publication.
5Androgen suppression and radiation vs radiation alone for prostate cancer: a randomized trialNCT00116220PMID 18212313
D'Amico AV et al. - JAMA (2008) - RCT (long-term follow-up) - 206 patients
Median follow-up 7.6 years. Significant increase in all-cause mortality risk for RT alone vs RT+AST (HR 1.8, 95% CI 1.1-2.9, p=0.01). Benefit appeared limited to men with no/minimal comorbidity (HR 4.2, 95% CI 2.1-8.5, p<0.001). Men with moderate/severe comorbidity showed no survival benefit from adding AST (HR 0.54, p=0.08).
Limitations: Post-hoc subgroup analysis by comorbidity. Not powered for subgroup comparisons.
6Two-year results of treatment with depot leuprolide acetate for central precocious pubertyPMID 1403402
Neely EK, Hintz RL, Parker B, et al. - The Journal of Pediatrics (1992) - Prospective cohort - 15 children with central precocious puberty
Children received 6-15mg IM every 4 weeks for 2 years. Pubertal progression ceased in all patients. Predicted adult height increased by 5.52 cm at 18 months. Estradiol fell from 3.3 to 0.60 ng/dL in girls. FSH suppressed to <1 IU/L. IGF-1 progressively declined. One sterile abscess in 15 children.
Limitations: Small, nonrandomized pediatric study. Older hormone assays.
7Phase 3 Trial of a Small-volume Subcutaneous 6-Month Duration Leuprolide Acetate Treatment for Central Precocious PubertyPMID 32738042
Klein KO, Freire A, Gryngarten MG, et al. - The Journal of Clinical Endocrinology and Metabolism (2020) - Phase 3 open-label trial - 64 GnRHa-naive children with CPP
Two 45mg SC doses (0.375 mL) at weeks 0 and 24 suppressed post-stimulation LH <4 IU/L in 87% at week 24 and 88% of girls at week 48. Growth velocity fell from 8.9 to 6.0 cm/year. Bone age advancement slowed. Recently FDA-approved 6-month formulation.
Limitations: Single-arm open-label design. Small male sample (2 boys). 48-week primary follow-up.
8Ulipristal acetate versus leuprolide acetate for uterine fibroidsNCT00740831PMID 22296076
Donnez J, Tomaszewski J, Vazquez F, et al. - The New England Journal of Medicine (2012) - RCT (double-blind, noninferiority) - 307 women with symptomatic fibroids and excessive uterine bleeding
Leuprolide 3.75mg IM monthly controlled bleeding in 89% of women by week 13. Median time to amenorrhea 21 days. Moderate-to-severe hot flashes in 40% (vs 10-11% with ulipristal). Ulipristal was noninferior to leuprolide for bleeding control.
Limitations: Leuprolide was active comparator, not investigational focus. Treatment limited to 3 months before surgery.
9Improved Outcomes with Enzalutamide in Biochemically Recurrent Prostate Cancer (EMBARK)NCT02319837PMID 37851874
Freedland SJ, de Almeida Luz M, De Giorgi U, et al. - The New England Journal of Medicine (2023) - Phase 3 RCT - 1068 patients (3 arms of approximately 355 each)
Enzalutamide + leuprolide: 5-year metastasis-free survival 87.3% vs 71.4% for leuprolide alone (HR 0.42, 95% CI 0.30-0.61, p<0.001). Enzalutamide monotherapy also superior (HR 0.63, p=0.005). No new safety signals. Quality-of-life preserved.
Limitations: Manufacturer-funded (Pfizer/Astellas). Open to potential conflicts of interest.
10Enzalutamide and Quality of Life in Biochemically Recurrent Prostate Cancer (EMBARK PRO analysis)NCT02319837PMID 38320501
Freedland SJ, Gleave M, De Giorgi U, et al. - NEJM Evidence (2023) - Phase 3 RCT (PRO analysis) - 1068 patients
PRO analysis of EMBARK: enzalutamide combination and monotherapy preserved health-related quality of life vs leuprolide alone. Median TTCD for worst pain: 80.0 months (combination) vs 66.27 months (leuprolide alone).
Limitations: PRO analysis is secondary endpoint. Open to subjective reporting bias. Manufacturer-funded.
11Differential behavioral effects of gonadal steroids in women with and in those without premenstrual syndromePMID 9435325
Schmidt PJ et al. - The New England Journal of Medicine (1998) - RCT (double-blind, crossover) - 20 women with PMS + 15 normal controls
Leuprolide significantly decreased PMS symptoms vs baseline and placebo. Reintroduction of estradiol or progesterone during continued leuprolide caused symptom recurrence in PMS women but not in controls. Demonstrated PMS represents abnormal response to normal hormonal changes.
Limitations: Small sample size (N=20). Only 10 women entered crossover phase.
12Differential Effects of Ovarian Steroids in Women With and Without Premenstrual Dysphoric Disorder: A Replication and Extension of FindingsPMID 41030005
Wei SM et al. - The American Journal of Psychiatry (2025) - Replication study (prospective, controlled) - 34 women with PMDD + 76 healthy participants
Confirmed ovarian suppression with leuprolide eliminated PMDD symptom cyclicity. Symptoms emerged during estradiol and progesterone addback in PMDD women but not healthy controls. Irritability and mood swings tied more closely to progesterone than estradiol.
Limitations: Open-label hormone administration. 10 of 34 PMDD patients were from original 1998 cohort.
13Therapeutic impact of leuprorelin acetate on spinal and bulbar muscular atrophy: pre- and post-marketing observational studyPMID 41258507
Hashizume A et al. - Journal of Neurology (2025) - Observational (self-controlled trend-shift analysis) - 91 genetically confirmed SBMA patients
Leuprolide significantly slowed SBMA disease progression. Annual ALSFRS-R decline improved from approximately 0.5 to approximately 0.2 points post-treatment. Subgroup analysis supported benefit of early intervention.
Limitations: Observational, not randomized. Self-controlled design. Slowly progressive disease limits statistical power.
14Increased pregnancy rates after ultralong postoperative therapy with gonadotropin-releasing hormone analogs in patients with endometriosisPMID 12372452
Rickes D et al. - Fertility and Sterility (2002) - RCT (prospective, randomized, controlled) - 110 patients with stage II-IV endometriosis
GnRH-a for 6 months after surgery followed by up to 3 ART cycles resulted in higher pregnancy rate per patient vs ART alone immediately after surgery.
Limitations: Single center. Protocol details for GnRH-a regimen not fully specified in abstract.
15Ultralong administration of gonadotropin-releasing hormone agonists before in vitro fertilization improves fertilization rate but not clinical pregnancy rate in women with mild endometriosisNCT01269125PMID 32147182
Kaponis A et al. - Fertility and Sterility (2020) - RCT (prospective, randomized, controlled) - 400 infertile women with mild endometriosis + 200 tubal factor controls
3 months GnRH-a before IVF significantly reduced follicular fluid cytokines and improved fertilization rate (72.7% vs 61.7%) but did not significantly improve implantation rate, embryo quality, or clinical pregnancy rate.
Limitations: Only mild endometriosis studied. Primary endpoint (pregnancy rate) not met.
16Limosilactobacillus reuteri NCU-37 alleviates leuprorelin-induced perimenopausal syndrome in infertile women by modulating the gut microbiota: a randomized controlled trialPMID 41399984
Wu X et al. - Food & Function (2026) - RCT - 100 infertile women with LIPS + 50 healthy controls
Probiotic NCU-37 significantly reduced Modified Kupperman Index (15.0 vs 8.0, p<0.01), HAMA anxiety (11.5 vs 7.0, p<0.01), HAMD depression (9.0 vs 7.0, p<0.01). Increased serum AMH, E2, FSH, LH (p<0.05) and pregnancy rate.
Limitations: Single-center study. Relatively small sample.
17Effectiveness and Safety of Postoperative Medical Treatments Following Fertility-Preserving Surgery for Endometriosis: A Network Meta-AnalysisPMID 41017486
Xiong Y et al. - BJOG (2026) - Network meta-analysis (Bayesian) - 16 RCTs, 1605 participants, 10 drugs evaluated
Only LNG-IUS significantly reduced endometriosis recurrence rates (OR 0.12, 95% CI 0.02-0.63) and showed greatest VAS pain reduction. Leuprolide was evaluated but not the most effective option for post-surgical recurrence prevention.
Limitations: Network meta-analysis with indirect comparisons. Heterogeneity across included RCTs.
18Interval to testosterone recovery after hormonal therapy for prostate cancer and risk of deathPMID 19395184
D'Amico AV et al. - International Journal of Radiation Oncology, Biology, Physics (2009) - Post-hoc analysis of RCT - 102 men (randomized to RT + HT from 206-patient RCT)
57/102 men (56%) had testosterone recovery time >2 years. As TTR increased, death risk decreased (adjusted HR 0.60, 95% CI 0.43-0.84, p=0.003). None with TTR >2 years died of prostate cancer. Benefit limited to men with no/minimal comorbidity.
Limitations: Post-hoc postrandomization analysis. Subgroup analysis of moderate-sized trial.
19Prostate-Specific Antigen Failure and Risk of Death Within Comorbidity Subgroups Among Men With Unfavorable-Risk Prostate Cancer Treated in a Randomized TrialPMID 27601545
Giacalone NJ et al. - Journal of Clinical Oncology (2016) - Long-term follow-up of RCT - 206 men (median follow-up 16.62 years)
156/206 men (76%) died, 29 (19%) of prostate cancer. PSA failure associated with increased all-cause mortality in men with no/minimal comorbidity (adjusted HR 1.59, 95% CI 1.03-2.46, p=0.04).
Limitations: Post-hoc subgroup analysis. Original trial not powered for these comparisons.
20Safety and Dosing of Relugolix with Novel Hormonal Therapy for Advanced Prostate CancerNCT04666129PMID 37060432
De La Cerda J et al. - Targeted Oncology (2023) - Phase I clinical trial - 25 men
Transition from leuprolide to relugolix (with abiraterone or apalutamide) showed favorable safety and tolerability. Castrate testosterone levels maintained after transitioning.
Limitations: Small Phase I study. Interim analysis. Open-label.
21Prolonged oral GnRH-antagonist administration before euploid embryo transfer in patients with endometriosis: a prospective randomized pilot non-inferiority trialPMID 41092830
Surrey ES et al. - Reproductive BioMedicine Online (2025) - RCT (pilot, non-inferiority) - 30 patients
Oral elagolix (200mg BID x 56 days) showed equivalent outcomes to leuprolide depot before euploid embryo transfer in endometriosis: live birth rates 87% vs 80% (p=0.62).
Limitations: Very small sample (N=30). Pilot study. Not powered for definitive non-inferiority.