Leuprorelin Acetate - Uses, Dosage, Side Effects, Drug Warnings, and Precautions

Overview:

Leuprorelin acetate is a synthetic nonapeptide drug that functions as a gonadotropin-releasing hormone (GnRH) receptor agonist. This medication works by acting on the GnRH receptors in the pituitary gland. This leads to reduced secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which, in turn, decreases gonadal sex steroid production, such as testosterone and estrogen.

Leuprorelin acetate was approved on April 9, 1985, by the US FDA (United States Food and Drug Administration) to be used for advanced prostate cancer. The use of the medication was considered important since it suppressed the testosterone level in a cancerous body that requires control to treat cancer effectively.

Later, on January 26, 1989, the FDA approved Leuprorelin acetate for monthly intramuscular injection specifically for the palliative treatment of advanced prostate cancer. The depot formulation allows for a slow and sustained drug release, providing more convenient dosing than daily injections.

Drug Group:

Leuprorelin acetate belongs to the drug group known as gonadotropin-releasing hormone (GnRH) agonists or LHRH agonists.

Indications

Leuprorelin acetate is indicated in advanced prostatic cancer primarily for palliative treatment to help manage symptoms and slow disease progression. It works by suppressing testosterone production, which is a key driver of prostate cancer growth.

Dosage Forms and Available Strengths

Leuprolide acetate is available in injection form as follows for the therapy of advanced prostatic cancer:

• 7.5 mg (milligrams) with one monthly administration - 1 injection every 4 weeks.

• 22.5 mg with a three-month administration - 1 injection every 12 weeks.

• 30 mg is given four times a month - 1 injection every 16 weeks.

• 45 mg with the six-month administration - 1 injection every 24 weeks.

For Patients

How Does Leuprorelin Acetate Work for Advanced Prostate Cancer?

Leuprorelin acetate is used to treat advanced prostate cancer by lowering testosterone levels.

• Prostate cancer cells need testosterone to grow.

• Leuprorelin acetate is a GnRH agonist.

• At first, it briefly increases testosterone levels.

• With continued use, the body stops responding to the hormone signal.

• Testosterone levels then fall to very low levels.

• Low testosterone slows down or stops cancer growth.

• This is very helpful in advanced and metastatic prostate cancer.

• The medicine is given as long-acting injections, so dosing is easy and less frequent.

What Are the Clinical Uses of Leuprorelin Acetate?

Leuprorelin acetate (also called leuprolide acetate) is used in several hormone-related conditions:

• Prostate Cancer: Lowers testosterone to slow cancer growth.

• Endometriosis: Lowers estrogen to reduce pain and tissue growth.

• Uterine Fibroids: Shrinks fibroids and reduces heavy bleeding before surgery.

• Precocious Puberty: Delays early puberty by blocking sex hormones.

• Ovarian Hyperstimulation Syndrome (OHSS): Helps control hormone levels during fertility treatment.

• Breast Cancer: Used in premenopausal women with hormone-sensitive breast cancer.

How Is Leuprorelin Acetate Administered?

Leuprorelin acetate is given only under a doctor’s supervision.

• It is used mainly to treat prostate cancer.

• Treatment is usually continued even if the cancer becomes castration-resistant.

• This applies to both non-metastatic and metastatic disease.

Injection Schedule

• 7.5 mg (1 month): One injection every 4 weeks.

• 22.5 mg (3 months): One injection every 12 weeks.

• 30 mg (4 months): One injection every 16 weeks.

• 45 mg (6 months): One injection every 24 weeks.

• Each dose is given after reconstitution.

• Do not mix with other formulations.

Reconstitution and Injection Procedure

• Check the powder before use.

• Do not use it if clumps or hard particles are seen.

• The liquid (diluent) must be clear and colorless.

• Follow the instructions for the prefilled dual-chamber syringe.

• Shake gently until the mixture looks even.

• Do not use it if the powder does not dissolve properly.

• Inject the medicine into a muscle.

• Injection sites include the buttock, thigh, or shoulder.

• Change the injection site each time.

• After injection, activate the safety device.

• Dispose of the syringe safely according to local rules.

What Are the Side Effects of Leuprorelin Acetate?

Leuprorelin acetate can cause side effects because it lowers testosterone levels in the body.

Common side effects (seen in fewer patients)

• General:

  • Pain (23.2%).

  • Infection (5.4%).

• Heart and Blood Vessels:

  • Hot flashes (57.1%).

• Digestive System:

  • Stomach or gut problems (14.3%).

• Metabolism:

  • Swelling of hands or feet (edema) (14.3%).

• Nervous System:

  • Reduced sexual desire (5.4%).

• Reproductive System:

  • Breathing-related problems (10.7%).

• Urinary and Reproductive System:

  • Urination problems (12.5%).

  • Erectile problems (5.4%).

  • Shrinking of testicles (5.4%).

Some effects, such as low sex drive and erectile problems, happen because testosterone levels are low.

Less common side effects (seen in more patients)

• General:

  • Weakness.

  • Fever.

  • Pain or redness at the injection site.

• Heart:

  • Chest pain (angina).

  • Heart failure.

• Digestive System:

  • Loss of appetite.

  • Stomach ulcers.

• Lungs:

  • Emphysema (damage to air sacs).

  • Fluid buildup in the lungs.

• Skin or Urinary System:

  • Hair or skin problems.

  • Breast enlargement.

  • Urinary tract infection (UTI).

Laboratory Test Changes

Changes may be seen in:

• Albumin.

• Hemoglobin.

• Blood urea nitrogen (BUN).

• Creatinine.

• Cholesterol.

• Liver enzymes.

• White blood cell count.

Doctors are not sure how important these changes are.

What Should You Tell Your Doctor Before Taking Leuprorelin Acetate?

• Allergies: Tell your doctor if you are allergic to Leuprolide or similar medicines like Histrelin or Goserelin.

• Medicines: Share a full list of medicines, vitamins, and supplements. This includes heart medicines, steroids, and antidepressants.

• Medical History: Tell your doctor if you have had bone thinning, depression, seizures, diabetes, spine cancer spread, heart rhythm problems, or urine issues.

• Alcohol and Smoking: Inform your doctor about long-term alcohol or tobacco use.

• Pregnancy and Breastfeeding:

  • This medicine is not safe.

  • Use non-hormonal birth control.

  • Tell your doctor right away if you become pregnant.

• Other Symptoms: Report unusual vaginal bleeding immediately.

Dietary Considerations

Continue your normal diet unless your doctor advises changes.

Missed Dose

• If you miss an injection appointment, contact your healthcare provider.

• They will reschedule it for you.

Overdose

• No overdose cases have been reported in humans.

• Very high doses in animal studies caused breathing problems and low activity.

• Human studies using high doses showed no new serious side effects.

Other Important Information

• Keep all doctor and lab appointments.

• Blood tests may be needed to check how well the medicine is working.

• Check blood sugar and HbA1c regularly.

• Keep a written list of all medicines for emergencies or doctor visits.

Storage and Handling

Storage and disposal of Leuprolide Acetate

Leuprolide acetate must be stored and discarded safely.

Storage

• Store at room temperature.

• Ideal temperature is 25°C (77°F).

• Short-term temperature changes between 15 to 30°C (59 to 86°F) are allowed.

• Keep the medicine in its original container.

• Protect it from direct light.

• Keep out of reach of children.

Disposal

• Place used needles and syringes in an FDA-approved sharps container.

• Do not flush the medicine down the toilet.

• Do not throw it in the household trash.

• Return unused or expired medicine to a pharmacy or local take-back program.

For Doctors

Chemical Taxonomy

Leuprolide acetate is a synthetic analog of GnRH or gonadotropin-releasing hormone with greater potency.

Leuprolide Acetate Formulations:

• 7.5 mg (1 month): Prefilled dual-chamber syringe for monthly intramuscular injection. Contains leuprolide acetate, gelatin, DL-lactic and glycolic acids copolymer, and D-mannitol.

• 22.5 mg (3-Month): For injection every 12 weeks. Contains leuprolide acetate, polylactic acid, and D-mannitol.

• 30 mg (4-Month): For injection every 16 weeks. Contains leuprolide acetate, polylactic acid, and D-mannitol.

• 45 mg (6-Month): For injection every 24 weeks. Contains leuprolide acetate, polylactic acid, D-mannitol, and stearic acid.

All formulations include a diluent with carboxymethylcellulose sodium, D-mannitol, polysorbate 80, water, and glacial acetic acid to control pH.

What Are the Pharmacological Actions of Leuprorelin Acetate?

1. Mechanism of Action:

Leuprolide acetate, a GnRH agonist, initially stimulates gonadotropin release, but with continuous use, it suppresses ovarian and testicular steroid production. This effect is reversible once the drug is stopped. It can also stop the growth of hormone-dependent tumors and cause atrophy of reproductive organs.

2. Pharmacodynamics:

When Leuprolide is first started, it briefly raises LH and FSH hormones, which causes a short-term increase in testosterone in men and estrogen in women.

With continuous use, leuprolide then switches off LH and FSH production. As a result:

• In men, testosterone falls to very low (castrate) levels.

• In women, estrogen drops to postmenopausal levels.

This usually happens within 2-4 weeks.

Leuprolide does not work if taken by mouth.

3. Pharmacokinetics:

• Absorption: Plasma concentrations vary by form, showing an initial peak followed by a steady-state concentration over time.

• Distribution: Leuprolide binds to 43 to 49 percent plasma proteins, with a distribution volume of 27 L (liters).

• Elimination: It has a systemic clearance of 7.6 L/h (liters per hour) and a half-life of approximately 3 hours, with less than 5% excreted in the urine.

Warnings and Precautions

• Tumor Flare: Serum testosterone levels may increase to approximately 50 percent above baseline during the first weeks of Leuprorelin Acetate therapy. This can cause transient exacerbation of symptoms, including bone pain and, in isolated instances, ureteral obstruction or spinal cord compression that may result in paralysis with or without fatal consequences. Patients with metastatic vertebral lesions or urinary tract obstruction should be closely monitored during this period.

• Hyperglycemia and Diabetes: Hyperglycemia and the risk of developing diabetes have been reported in men on GnRH agonists. Monitoring blood glucose and HbA1c (glycated hemoglobin) is essential, and current medical standards should be followed to manage hyperglycemia or diabetes.

• Cardiovascular Disease: GnRH agonists have been associated with an increased risk of myocardial infarction, stroke, and sudden cardiac death. The risk is low; however, these factors must be carefully considered during the treatment decision process, considering all the cardiovascular risk factors for patients. Patient surveillance for signs of cardiovascular disease should also be performed in accordance with available clinical practice guidelines.

• QT or QTc Interval Prolongation: Some hormone treatments for prostate cancer (androgen deprivation therapy) can slow the heart’s electrical system. This may prolong the QT or QTc interval on an ECG, increasing the risk of abnormal heart rhythms. This risk is higher in people who:

  • Already have long QT syndrome.

  • Have heart failure.

  • Have low potassium or magnesium levels.

  • Take other medicines that affect heart rhythm

To reduce risk:

• Fix low electrolyte levels (like potassium or magnesium).

• Doctors may perform regular ECGs and blood tests to monitor heart rhythm and electrolyte levels.

• Convulsions: Postmarketing reports have described convulsions in patients receiving leuprolide acetate, regardless of whether risk factors such as a history of epilepsy, cerebrovascular disorders, or concurrent medications like SSRIs and bupropion were present. Patients who develop convulsions should be treated based on an appropriate medical response.

• Laboratory Monitoring: Monitor testosterone levels after Leuprorelin Acetate administration to confirm they decrease castrate levels (<50 ng/dL) within four weeks. This is expected in most patients receiving 7.5 mg (1-month), 22.5 mg (3-month), 30 mg (4-month), or 45 mg (6-month) formulations.

• Embryo-Fetal Toxicity: Leuprorelin Acetate may cause fetal harm if administered during pregnancy. Animal studies have shown adverse effects on embryos at doses lower than the human equivalent. Pregnant patients and individuals with reproductive potential should be educated about fetal hazards.

Non-Clinical Toxicity

Two-year studies in rats showed a dose-related increase in pituitary hyperplasia and adenomas, along with pancreatic and testicular tumors at higher doses. Tumors or pituitary abnormalities were not detected in mice at 60 mg/kg. Patients have used leuprolide acetate for up to 3 years without evidence of pituitary abnormalities.

Genotoxicity studies showed no mutagenic or chromosomal effects. Leuprolide may reduce fertility in both males and females. In rats, it caused reproductive organ atrophy and suppressed reproductive function at doses as low as 1/30 of the human dose. These effects were reversible after stopping the drug.

What Are the Contraindications of Leuprorelin Acetate?

Leuprorelin acetate is contraindicated in individuals with:

• Known hypersensitivity to GnRH agonists or any excipients in Leuprorelin acetate.

• Reports of anaphylactic reactions to GnRH agonists have been documented in medical literature.

What Are the Drug Interactions of Leuprorelin Acetate?

No pharmacokinetic drug interaction data are available for leuprorelin acetate, and no specific interaction studies have been conducted. However, as documented in studies, leuprorelin acetate is primarily degraded by peptidases rather than cytochrome P-450 enzymes. Approximately 46 percent are bound to plasma proteins, making significant drug interactions unlikely.

Clinical Studies

1. Leuprorelin Acetate 7.5 MG for 1-Month Administration:

A clinical study with 56 patients showed that Leuprorelin acetate 7.5 mg reduced serum testosterone to castrate levels in 94 percent of patients within 30 days. Objective tumor response analysis showed 77 percent of patients had no disease progression at week 12 and 84 percent at week 24. PSA levels decreased or normalized in most patients.

2. Leuprorelin Acetate 22.5 MG for 3-Month Administration:

In 92 patients, serum testosterone was suppressed to castrate levels within 30 days in 95%. 85% of patients showed no disease progression, and 71% had a ≥90% decrease in PSA levels.

3. Leuprorelin Acetate 30 MG for 4-Month Administration:

In a study of 49 patients, testosterone was suppressed to castrate levels within 30 days in 94 percent of patients. 86% of patients had no disease progression at week 16, and 50% of patients with elevated PSA levels had normalized PSA levels by week 16.

4. Leuprorelin Acetate 45 MG for 6-Month Administration:

In 151 patients, serum testosterone was suppressed to castrate levels in 93.4 percent from week 4 to week 48. Testosterone suppression was achieved in 93 percent of patients, and eight patients had testosterone elevations above castrate levels.

Use in Specific Populations

• Pregnancy - Leuprorelin acetate may harm the fetus and should not be used during pregnancy. Animal studies showed fetal malformations and toxicity at doses lower than the human equivalent.

• Lactation - It is unknown if Leuprorelin acetate passes into breast milk. Breastfeeding is not recommended in patients due to potential risks to the child.

• Reproductive Potential - Leuprorelin acetate may impair fertility in males based on its mechanism of action and animal studies.

• Pediatric Use - Leuprorelin acetate is used in children with central precocious puberty.

• Geriatric Use - The drug is effective and safe in patients aged 65 and older based on prostate cancer trials.