Triptorelin is a gonadotropin releasing hormone (GnRH) agonist that is a potent inhibitor of the synthesis of testosterone (in men) and estrogen (in women) and is used to treat advanced prostate cancer. Triptorelin is associated with a low rate of transient serum enzyme elevations during therapy, but has not been linked convincingly to cases of clinically apparent acute liver injury.
Triptorelin (trip" toe rel' in) is a decapeptide analogue of gonadotropin releasing hormone (GnRH) that acts on the pituitary to cause the synthesis and release of luteinizing hormone (LH) and follicle stimulating hormone (FSH), two gonadotropins that act on the male testes to stimulate the production of testosterone and on the female ovaries to induce synthesis of estrogen. Triptorelin and other GnRH agonists cause an initial surge of gonadotropin release, but then lead to down-regulation of their synthesis and secretion which results in a decline in testosterone and estrogen production. Triptorelin, alone or in combination with other antiandrogens, has been found to be palliative in advanced prostate cancer and as effective as surgical castration. Triptorelin was approved for use in the United States for prostate cancer in 2000 and is still widely used, being considered a first line treatment of this hormone responsive malignancy. Triptorelin is available generically and under the brand name Trelstar in an injectable suspension for intramuscular depot administration every 4 weeks (3.75 mg), 12 weeks (11.25 mg) or 24 weeks (22.5 mg). Triptorelin and the other GnRH analogues cause a profound hypogonadism ("chemical castration") and its common side effects are typical of androgen deprivation, including hot flashes, loss of libido, erectile dysfunction, depression, nausea, diarrhea, weight gain and fluid retention. Rare, but potentially severe adverse events can include immediate hypersensitivity reactions, pituitary apoplexy and, with long term use, weight gain, metabolic changes, diabetes and osteoporosis.
Long term triptorelin is associated with serum enzyme elevations in 2% to 5% of patients, although the elevations are rarely above three times the upper limit of normal (<1%). The enzyme elevations are usually mild, asymptomatic and resolve even without dose modification or drug discontinuation. Triptorelin has not been linked convincingly to cases of acute, clinically apparent liver injury with jaundice.
Mechanism of Injury
The cause of the minor serum enzyme elevations that can occur during triptorelin therapy is unknown. Triptorelin is a decapeptide similar to GnRH and is metabolized locally in tissue and not by the hepatic cytochrome P450 system. Some serum enzyme elevations may be caused by nonalcoholic fatty liver arising because of weight gain or metabolic changes caused by the androgen deprivation state induced by the GnRH agonist.
Outcome and Management
The serum enzyme elevations during triptorelin therapy rarely require dose modification or drug discontinuation and should instead lead to investigation of other possible causes of liver injury. There is no evidence to indicate that there is cross sensitivity to liver injury among the various GnRH analogues.
REPRESENTATIVE TRADE NAMES
Triptorelin – Generic, Trelstar®
Product labeling at DailyMed, National Library of Medicine, NIH
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References updated: 30 July 2015
Zimmerman HJ. Hepatotoxic effects of oncotherapeutic and immunosuppressive agents. In, Zimmerman HJ. Hepatotoxicity: the adverse effects of drugs and other chemicals on the liver. 2nd ed. Philadelphia: Lippincott, 1999, pp. 699. (Expert review of hepatotoxicity published in 1999; the GnRH analogues such as triptorelin are not discussed).
Chitturi S, Farrell GC. Estrogen receptor antagonists. Adverse effects of hormones and hormone antagonists on the liver. In, Kaplowitz N, DeLeve LD, eds. Drug-induced liver disease. 3rd ed. Amsterdam: Elsevier, 2013, pp. 610-2. (Review of hepatotoxicity of hormonal products; does not discuss the GnRH agonists such as triptorelin).
Moy B, Lee RJ, Smith M. Gonadotrophin-releasing hormone agonists and antagonists. Natural products in cancer chemotherapy: hormones and related agents. In, Brunton LL, Chabner BA, Knollman BC, eds. Goodman & Gilman's the pharmacological basis of therapeutics. 12th ed. New York: McGraw-Hill, 2011, pp. 1764. (Textbook of pharmacology and therapeutics).
Triptorelin pamoate (Trelstar). Med Lett Drugs Ther 2002; 44 (1132): 51-2. PubMed Citation (Concise review of the mechanism of action, efficacy, safety and costs of triptorelin for prostate cancer shortly after its approval in the United States mentions that adverse effects are similar to those of goserelin; does not mention ALT elevations or hepatotoxicity).
Heyns CF, Simonin MP, Grosgurin P, Schall R, Porchet HC; South African Triptorelin Study Group. Comparative efficacy of triptorelin pamoate and leuprolide acetate in men with advanced prostate cancer. BJU Int 2003; 92: 226-31. PubMed Citation (Among 284 men with prostate cancer treated with triptorelin or leuprolide in 9 monthly injections, both beneficial and adverse effects were similar and "there were no substantial changes in laboratory data"; ALT levels were not specifically mentioned).
Lundström EA, Rencken RK, van Wyk JH, Coetzee LJ, Bahlmann JC, Reif S, Strasheim EA, et al. Triptorelin 6-month formulation in the management of patients with locally advanced and metastatic prostate cancer: an open-label, non-comparative, multicentre, phase III study. Clin Drug Investig 2009; 29: 757-65. PubMed Citation (Among 120 patients given triptorelin in 6 month formulation [22.5 mg] for one year, the most common side effects were hot flashes [72%], erectile dysfunction [10%] and injection site reactions [7%], and one patient had a rise in ALT levels [peak = 60 U/L] on day 337).
Rabaglio M, Ruepp B; Soft/Text/Perche Steering Committee. Death due to liver failure during endocrine therapy for premenopausal breast cancer. Acta Oncol 2010; 49: 874-6. PubMed Citation (Among 4500 women enrolled in an international trial of endocrine therapy of premenopausal breast cancer comparing tamoxifen and exemestane combined with ovarian suppression often with triptorelin, 2 developed liver failure: 50 year old on endocrine therapy for two years developed suspected acute alcoholic hepatitis and died 1 month later [bilirubin 23.2 mg/dL, ALT 182 U/L, AST 294 U/L, GGT 2623 U/L, Alk P 382 U/L]; 36 year old woman on endocrine therapy including tamoxifen for 3 years developed nonspecific symptoms and hepatomegaly and died suddenly, autopsy showing cirrhosis with steatosis, possibly due to or exacerbated by tamoxifen; in neither case could triptorelin be convincingly implicated).
Crawford ED, Phillips JM. Six-month gonadotropin releasing hormone (GnRH) agonist depots provide efficacy, safety, convenience, and comfort. Cancer Manag Res 2011; 3: 201-9. PubMed Citation (Review of results on two GnRH agonist depot formulations for advanced prostate cancer that allow for every 6 month administration [leuprolide and triptorelin], both of which provide sustained testosterone suppression and have adverse side effects similar to other GnRH agonist formulations; mentions a single episode of minor asymptomatic ALT [60 U/L] and AST [65 U/L] elevations in a patient receiving triptorelin [Ludström 2009]).
Ploussard G, Mongiat-Artus P. Triptorelin in the management of prostate cancer. Future Oncol 2013; 9: 93-102. PubMed Citation (Review of the efficacy and safety of triptorelin as therapy of prostate cancer focusing upon 1 vs 3 vs 6 monthly formulations; no mention of ALT elevations or hepatotoxicity).
Björnsson ES, Bergmann OM, Björnsson HK, Kvaran RB, Olafsson S. Incidence, presentation and outcomes in patients with drug-induced liver injury in the general population of Iceland. Gastroenterology 2013; 144: 1419-25. PubMed Citation (In a population based study of drug induced liver injury from Iceland, 96 cases were identified over a 2 year period, but none were attributed to triptorelin or any of the GnRH analogues).
Chalasani N, Bonkovsky HL, Fontana R, Lee W, Stolz A, Talwalkar J, Reddy KR, et al.; United States Drug Induced Liver Injury Network. Features and outcomes of 899 patients with drug-induced liver injury: The DILIN Prospective Study. Gastroenterology 2015; 148: 1340-1352. PubMed Citation (Among 899 cases of drug induced liver injury enrolled in a US prospective study between 2004 and 2013, none were attributed to triptorelin or any of the GnRH analogues).
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