abarelix

Action and Spectrum

Actions and Spectrum: 

It belongs to the gonadotropin-releasing hormone antagonist class and works by suppressing the male hormone testosterone which can fuel prostate cancer cell growth.  

Abarelix blocks the release of luteinizing hormone and follicle-stimulating hormone, which stimulate the testes to produce testosterone.  

This inhibits LH and FSH by reducing testosterone levels in the body, suppression of testosterone is crucial in treating prostate cancer as many cells rely on it for growth.  

Abarelix has a rapid onset of action and quickly reducing testosterone levels which relieves symptoms associated with prostate cancer. It is typically used as a palliative treatment in advanced prostate cancer cases where the disease has spread or is unresponsive to other treatments. 

Drug Interaction

Adverse Reaction

Frequency not defined 

Pain 

Fatigue 

Sleep Disturbance 

Back Pain 

Hot Flushes 

Black Box Warning

Black Box Warning: 

None 

Contraindication / Caution

Contraindication/Caution: 

Contraindication 

It is used to treat prostate cancer but it should not be used by individuals with known hypersensitivity or severe allergic reactions.  

It is intended for adult men and should not be used by women or children. Patients with severe allergic reactions to other GnRH agonists or antagonists may be at increased risk of hypersensitivity reactions.  

Abarelix is metabolized in the liver and its safety and efficacy have not been established in those with severe liver disease.  

It is not recommended for use in pregnancy or breastfeeding as it may adversely affect pregnancy and fetal development.  

Patients with a history of cardiovascular disease, including heart attacks or stroke may require careful monitoring when using abarelix as it can lead to temporary ECG changes and impact heart health. 

Caution 

Abarelix is a medication that may cause temporary electrocardiogram changes, which may impact heart health. Patients with a history of cardiovascular disease should be closely monitored during treatment. Liver function is not established and patients with severe liver disease should be closely monitored.  

Abarelix may initially increase testosterone levels before suppressing them which can temporarily worsen prostate cancer symptoms.  

Patients should be informed about this potential effect and healthcare providers may use additional medications to manage the flare.  

Abarelix may interact with other medications and patients must inform their healthcare provider about all medications, supplements, or herbal products. Certain medications, especially those affecting the heart’s electrical activity may require special consideration. 

Pregnancy / Lactation

Pregnancy/ Lactation 

Pregnancy consideration: 

US FDA pregnancy category: Not   assigned. 

Lactation: 

Excreted into human milk: Not   known. 

Pregnancy category: 

Category A: Satisfactory and well-controlled   studies show no risk to the fetus in the first or later trimester. 

Category B: There is no evidence of risk to the fetus   found in animal reproduction studies and there are not enough studies on   pregnant women. 

Category C: Adverse effects on the fetus found   with evidence in animal reproduction studies and no adequate evidence for an   effect in humans, care must be taken for potential risks in pregnant women. 

Category D: There is adequate data available with   sufficient evidence of human fetal risk from various platforms, but despite   potential risks may be used only in emergency cases for potential benefits. 

Category X: Drugs listed in this category   outweigh risks over benefits These category drugs should be prohibited for   pregnant women. 

Category N: There is no data available for the   drug under this category. 

Pharmacology

Pharmacology: 

Abarelix is a gonadotropin-releasing hormone (GnRH) antagonist used in treating advanced prostate cancer. It blocks GnRH binding to pituitary gland receptors inhibiting the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). This leads to a rapid suppression of testosterone production in the testes which is effectively inhibiting prostate cancer cell growth and proliferation. Abarelix provides relief from cancer related symptoms and potentially slows disease progression. Unlike GnRH agonists it does not induce a surge in testosterone that is making it a valuable option in specific clinical scenarios. 

Pharmacodynamics: 

Abarelix helps in treating advanced prostate cancer by blocking the actions of gonadotropin-releasing hormone, this hormone stimulates the release of luteinizing hormone and follicle-stimulating hormone (FSH) which stimulate the testes to produce testosterone. In prostate cancer the testosterone is crucial for cell growth and progression. It effectively suppresses testosterone production in the testes by blocking GnRH’s actions and reducing the release of LH and FSH. This process is known as medical castration that lowers testosterone levels typically seen after surgical castration. 

Pharmacokinetics: 

Absorption 

It is injected into the gluteal muscle allowing for controlled and sustained release of the medication over time ensuring slow and steady absorption into the bloodstream. 

Distribution 

It is distributed into the bloodstream and may bind to plasma proteins. Its target sites include the pituitary gland are where it affects gonadotropin releasing hormone receptors causing its pharmacological effects. 

Metabolism 

The abarelix’s metabolism study is limited with details about its pathways and metabolites not widely discussed in publicly accessible sources suggesting that the drug may undergo transformation in the liver or other tissues. 

Elimination and Excretion 

It is primarily eliminated through renal and hepatic routes with specific excretion pathways and metabolites requiring further research and may vary among individuals. 

Adminstartion

Administration: 

Abarelix is an injectable medication used for treating advanced prostate cancer. The injection site may alternate between left and right buttocks for subsequent injections to minimize injection site reactions.  It is supplied as a lyophilized powder which must be reconstituted with a specified diluent before administration. The frequency of abarelix injections depends on the patient response to therapy. Patient education is essential including information about the medication, potential side effects, and emergency procedures.  

Regular follow-up visits and prostate-specific antigen (PSA) levels monitoring are also necessary. Proper disposal of needles and syringes is essential to prevent accidental needlestick injuries. Local regulations should provide patients with instructions on safely disposing of used needles and syringes. 

Patient Information Leaflet

Patient   information leaflet 

Generic Name: abarelix 

Why do we use abarelix? 

Abarelix is used in oncology and urology to treat advanced prostate cancer. It belongs to the gonadotropin-releasing hormone antagonists class and is used to manage the cancer particularly in cases where it has spread beyond the prostate gland or other hormonal therapies have failed. It suppresses testosterone production by slowing down or shrinking the tumor and relieving cancer related symptoms. The treatment aims to achieve and maintain low testosterone levels known as medical castration.