Lupron Depot (Leuprolide Acetate)

Lupron Depot is a long-acting injectable form of leuprolide acetate, a synthetic gonadotropin-releasing hormone (GnRH) agonist. When given repeatedly, it first briefly raises luteinizing hormone (LH) and follicle-stimulating hormone (FSH), but then causes down-regulation of GnRH receptors in the pituitary. This leads to a sustained decrease in LH/FSH and hence a marked reduction of sex hormones (testosterone in men, estrogen in women) – effectively a “medical castration”. Lupron Depot is administered by intramuscular injection every 1–6 months (depending on the formulation and indication). It was first FDA-approved in 1985 and is marketed by AbbVie (no generic depot formulation is currently available.

Mechanism of Action

• GnRH Agonist: Leuprolide acetate mimics natural GnRH. It initially stimulates the pituitary to release LH/FSH, causing a transient surge in sex hormones (testosterone/estrogen). With continuous treatment, GnRH receptors become desensitized, and gonadotropin release is suppressed.
• Result: The net effect is greatly lowered testosterone in men or estrogen in women, which slows the growth of hormone-dependent tissues (e.g. prostate cancer cells or endometriotic implants).

Uses

Lupron Depot is FDA-approved for hormone-sensitive conditions in adults and children:

• Advanced prostate cancer: Testosterone suppression slows growth of metastatic prostate carcinoma. (Often combined with a short-term anti-androgen during the first 2–4 weeks to block the initial flare of testosterone).
• Endometriosis: In premenopausal women, Lupron Depot shrinks endometriotic lesions and relieves pelvic pain by reducing estrogen. (Treatment is typically limited to 3–6 months. Physicians often add a “add-back” low-dose progestin (like norethindrone) to mitigate hypoestrogenic side effects such as bone loss and hot flashes.)
• Uterine fibroids (leiomyomas): Short-term therapy (usually ≤3 months) to shrink fibroids and reduce heavy bleeding/anemia, often in preparation for surgery. (Fibroid symptoms usually recur after stopping therapy.)
• Central precocious puberty (CPP): In children (age ≥1 year) with early-onset puberty, Lupron Depot-Ped formulation suppresses premature LH/FSH release and halts pubertal progression.

These uses are hormone-suppressive: by lowering estrogen or testosterone, Lupron Depot controls symptoms of hormone-driven conditions.

Administration and Dosing

Lupron Depot is supplied as a pre-measured “depot” injection kit (powder plus diluent). It must be administered intramuscularly by a healthcare provider. Available injection intervals include monthly, 3-month, 4-month, and 6-month formulations. (For example, common regimens are 3.75 mg every month, 11.25 mg every 3 months, 30 mg every 3 months, or 45 mg every 6 months.) The specific dose and interval depend on the indication. For instance, in advanced prostate cancer a typical regimen might be 30 mg IM every 3 months, whereas endometriosis is often treated with 3.75 mg monthly. Because the first injection can transiently raise testosterone, men usually receive a short course of an anti-androgen drug during the first 2–4 weeks to prevent a “tumor flare” (worsening bone or urinary symptoms)

Side Effects and Adverse Reactions

Lowering sex hormones leads to various side effects similar to menopause or androgen deprivation. Common adverse reactions include:

• Vasomotor symptoms: Hot flashes, night sweats, and flushing. These are very common as estrogen/testosterone levels drop.
• Injection site reactions: Pain, swelling, redness or abscess at the IM injection site.
• Musculoskeletal pain: Arthralgias, back pain, bone or muscle aches. Some patients report generalized pain or fluid retention.
• Fatigue and weakness: Feeling tired or lacking energy, due to low sex steroids.
• Mood and cognitive changes: Mood swings, irritability, depression or anxiety. (Detailed monitoring is advised as emotional side effects can occur.)
• Headache/dizziness: Common neurologic complaints.
• Weight/metabolic changes: Increased weight or changes in blood lipids/glucose (features of “metabolic syndrome”). Patients may gain fat, lose muscle, or develop insulin resistance.
• Genitourinary: In women, vaginal dryness, itching or discharge; decreased libido. In men, decreased libido, erectile dysfunction, and testicular atrophy (shrinking of the testes) can occur. (These are due to very low testosterone.)
• Gastrointestinal: Nausea, vomiting, or other GI upset.

Long-term effects: Prolonged hormone suppression causes bone density loss (osteoporosis). Estrogen and testosterone normally preserve bone; without them, bone mass declines. For this reason, therapy duration is often limited (e.g. ≤6 months in endometriosis) and patients may receive calcium, vitamin D, or add-back hormones to protect bones. Heightened risk of fractures is a concern in chronic use.

Rare but serious: Some patients experience severe adverse events. Reported serious reactions include cardiovascular events (heart attacks, strokes), thromboembolic events, clinically significant depression, and serious skin reactions (e.g. erythema multiforme). These are uncommon, but clinicians should monitor for warning signs. Very rarely, patients with pituitary tumors may experience pituitary apoplexy (sudden headache/vomiting) when on GnRH agonists (this risk is noted in the drug labeling).

Precautions and Warnings

• Tumor Flare (Prostate Cancer): As noted, the initial treatment can temporarily increase testosterone before suppression. In men with prostate cancer, this flare can worsen bone pain, urinary difficulty or spinal cord compression. To prevent this, Lupron Depot is often started with a short course of an anti-androgen. Patients should report any worsening symptoms early.
• Bone Health: Long-term use reduces estrogen/testosterone and can cause osteoporosis. Bone density should be monitored (e.g. DEXA scans) if therapy exceeds ~6 months. In women, “add-back” of low-dose hormones can mitigate bone loss. Adequate calcium and vitamin D intake is advised.
• Pregnancy/Breastfeeding: Lupron Depot is contraindicated in pregnancy. It causes fetal harm and birth defects. Women of childbearing potential should use reliable non-hormonal contraception during treatment (pregnancy tests are recommended before starting). Hormonal birth control pills may be ineffective while on Lupron (because the drug suppresses ovarian function), so barrier methods (condoms, diaphragm) are advised. Breastfeeding is also discouraged during treatment.
• Fertility: Lupron Depot suppresses ovulation and spermatogenesis. It can cause temporary infertility (anovulation/azoospermia). In most cases fertility returns after stopping therapy (studies show normal hormone function can resume within months). Patients desiring children should discuss timing with their doctor.
• Pediatric Use: Lupron Depot-Ped is indicated only for true central precocious puberty in children ≥1 year. It should not be used in otherwise normal puberty. Growth, bone age and pubertal signs must be closely monitored in pediatric patients.
• Other Conditions: Caution in patients with risk factors for heart disease, seizures, or severe osteoporosis. Because Lupron Depot can cause fluid retention, edema or changes in blood pressure, patients with cardiovascular issues should be watched closely.

Additional Notes

• Formulations: Lupron Depot is available in specific depot strengths (e.g. 3.75 mg, 7.5 mg, 11.25 mg, 22.5 mg, 30 mg, 45 mg) for different dosing intervals. The pediatric form (Depot-Ped) has lower strengths suitable for small children. Doses are not interchangeable between adult and pediatric formulations.
• Brand vs. Generic: As of 2026, no generic version of the depot injection has been approved. All depot products are branded (currently AbbVie’s Lupron Depot).
• Related Drugs: Other GnRH agonists (e.g. triptorelin, goserelin, histrelin) have similar uses and mechanisms, but Lupron Depot specifically refers to leuprolide acetate in a depot injection form.

Summary: Lupron Depot is a powerful long-acting GnRH agonist injection that suppresses sex hormone production. It’s used mainly for advanced prostate cancer and hormone-responsive gynecologic conditions, as well as central precocious puberty in children. Because it creates a profound hypogonadal state, patients often experience menopausal-like side effects (hot flashes, low libido, bone loss, mood changes). Therapy is managed under specialty care, with monitoring for bone density and other risks. All information here is general; specific treatment decisions must be made with a qualified healthcare provider and the official prescribing information.