Histrelin

Pregnancy.

Patient with pre-existing cardiac disease, heart failure, history or risk factors for QT prolongation (e.g. congenital long QT syndrome, bradycardia, MI, stroke, frequent electrolyte abnormalities); pre-existing osteoporosis; history of seizure disorders, cerebrovascular disorders, CNS anomalies or tumours. Children. Lactation.

Significant: Seizures, psychiatric events (e.g. emotional lability symptoms, impatience, irritability, anger, and aggression), transient increase in testosterone and estradiol levels; pseudotumour cerebri or idiopathic intracranial hypertension, reduced bone mineral density and osteopenia (especially in adolescent children); CV effects (e.g. increased risk of MI, stroke). Rarely, pituitary apoplexy (manifested as visual or mental changes, headache, vomiting, CV collapse).
Injury, poisoning and procedural complications: Insertion site reactions (e.g. bruising, erythema, pain, tenderness, soreness, inflammation).
Investigations: Increased weight.
Nervous system disorders: Headache.
Potentially Fatal: Increased risk of sudden cardiac death.

Parenteral/SC: Z (Hormonal changes during therapy may lead to pregnancy loss. Contraindicated.)

Keep the implant arm clean and dry for 24 hours (avoid bathing and swimming). Refrain from heavy lifting or strenuous exertion of the insertion arm for 7 days after implantation.

Perform confirmatory tests for CPP diagnosis, including blood concentration of total sex steroids, LH, and FSH levels after stimulation with a GnRH analogue, and bone age assessment versus chronological age prior to treatment initiation. Monitor height and weight at baseline. Perform diagnostic brain imaging (to rule out intracranial tumours), pelvic/testicular/adrenal ultrasound (to rule out steroid-secreting tumours), human chorionic gonadotropin levels (to rule out chorionic gonadotropin-secreting tumours), and adrenal steroid levels (to exclude congenital adrenal hyperplasia). Monitor LH, FSH, testosterone and estradiol levels, 1 month after implantation then every 6 months thereafter; height and bone age every 6-12 months. Assess for signs and symptoms of pseudotumour cerebri, (e.g. headache, dizziness, tinnitus, nausea, blurred or loss of vision, diplopia, pain behind the eye or pain with eye movement) or the development or worsening of psychiatric symptoms and depression.

May interfere with the diagnostic test results of pituitary gonadotropic and gonadal functions conducted during and after treatment.

Description:
Mechanism of Action: Histrelin, a synthetic nonapeptide analogue of gonadotropin-releasing hormone (GnRH), is a potent inhibitor of gonadotropin secretion. It causes reversible down-regulation of GnRH receptors in the pituitary gland and desensitisation of pituitary gonadotropes, resulting in decreased levels of luteinising hormone (LH), follicle-stimulating hormone (FSH).
Onset: Ceased progression of sexual development and slowed linear growth velocity: Within 1 month.
Duration: Approx 12 months.
Pharmacokinetics:
Absorption: Bioavailability: 92%. Time to peak plasma concentration: 12 hours.
Distribution: Volume of distribution: Approx 58.4 ± 7.86 L. Plasma protein binding: Approx 70% ± 9%.
Metabolism: Metabolised in the liver via C-terminal dealkylation and hydrolysis.
Excretion: Terminal elimination half-life: Approx 4 hours.

Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 25077993, Histrelin. https://pubchem.ncbi.nlm.nih.gov/compound/Histrelin. Accessed Sept. 23, 2024.

Store between 2-8°C.

Other Drugs Affecting Hormonal Regulation

L02AE05 - histrelin ; Belongs to the class of gonadotropin releasing hormone analogues. Used in endocrine therapy.

Anon. Histrelin. AHFS Clinical Drug Information [online]. Bethesda, MD. American Society of Health-System Pharmacists, Inc. https://www.ahfscdi.com. Accessed 04/09/2024.

Brayfield A, Cadart C (eds). Histrelin. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 04/09/2024.

Histrelin. Gold Standard Drug Database in ClinicalKey [online]. Elsevier Inc. https://www.clinicalkey.com. Accessed 04/09/2024.

Histrelin. UpToDate Lexidrug, Lexi-Drugs Multinational Online. Waltham, MA. UpToDate, Inc. https://online.lexi.com. Accessed 04/09/2024.

Supprelin LA Implant (Endo USA, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 04/09/2024.

Supprelin LA Subcutaneous Implant (Endo Pharmaceuticals Inc.). U.S. FDA. https://www.fda.gov. Accessed 04/09/2024.