Testosterone isobutyrate, sold under the brand names Agovirin-Depot and Perandren M among others, is an androgen and anabolic steroid medication and a testosterone ester which is used for indications such as low testosterone levels in men and delayed puberty in boys.[1][4] It is available only in the Czech Republic and Slovakia.[1] The medication is administered by injection into muscle once every 1 to 2 weeks in males.[1] Unlike most other testosterone esters, which are provided as oil solutions, testosterone isobutyrate is formulated as a microcrystallineaqueous suspension.[1]
See also: Androgen replacement therapy § Medical uses, and Anabolic steroid § Medical
Testosterone isobutyrate is used in the treatment of hypogonadism in men and delayed puberty in adolescent boys.[1] It is also used in the treatment of Klinefelter's syndrome, aplastic anemia, Cushing's syndrome (as an anabolic to preserve lean body mass), postmenopausal osteoporosis in women, advanced breast cancer in women, breast pain in women, and cachexia.[1] Testosterone isobutyrate has been used in masculinizing hormone therapy for transgender men as well.[5][6]
Available forms[]
See also: Estradiol benzoate/testosterone isobutyrate
Testosterone isobutyrate is provided in the form of a 25 mg/mL microcrystallineaqueous suspension packaged in 2 mL ampoules (5 ampoules per box).[1] This equates to a dose of 50 mg per ampoule.[1] Testosterone isobutyrate (25 mg) is also available in combination with estradiol benzoate (2.5 mg) under the brand name Folivirin (1 mL ampoules).[7][8][9][10][11]
Side effects[]
See also: Anabolic steroid § Adverse effects, and Androgen replacement therapy § Adverse effects
Side effects of testosterone isobutyrate include virilization among others.[1]
Pharmacology[]
See also: Testosterone § Mechanism of action, and Anabolic steroid § Pharmacology
Testosterone isobutyrate is a prodrug of testosterone, and hence is an agonist of the androgen receptor, the biological target of endogenousandrogens like testosterone and dihydrotestosterone.[1] It produces both androgenic and anabolic effects, as well as weak estrogenic effects due to metabolism of testosterone into estradiol.[1]
In contrast to most other testosterone esters, which are used as amorphousoil solutions, testosterone isobutyrate is provided in the form of a microcrystallineaqueous suspension.[1] It has very low water solubility and forms a long-lasting microcrystalline depot within muscle upon intramuscular injection.[1] This respository slowly dissolves over time.[1] As a result, testosterone isobutyrate has a prolonged duration of action of approximately 2 weeks.[1][2][3] It is administered at intervals of once every 1 to 2 weeks in men.[1] Microcrystalline testosterone isobutyrate in aqueous suspension requires a larger needle (21 gauge) than oil solutions due to the presence of solid crystals in the suspension.[1] It can produce local irritation, pain, and redness upon injection.[1]
Chemistry[]
See also: Androgen ester and List of androgen esters § Testosterone esters
Testosterone isobutyrate, or testosterone 17β-(2-methylpropanoate), is a syntheticandrostanesteroid and a derivative of testosterone.[12][13] It is an androgen ester; specifically, it is the C17β 2-methylpropanoate (isobutyrate) ester of testosterone.[12][13]
History[]
Microcrystalline testosterone isobutyrate in aqueous suspension was first described in 1952.[1][14] It was introduced for medical use shortly thereafter.[1] Around the same time, testosterone enanthate in oil solution was introduced for medical use.[1] It became the dominant long-acting injectable form of testosterone, and limited the commercial success of testosterone isobutyrate.[1] The combination of microcrystalline estradiol benzoate and testosterone isobutyrate in aqueous suspension was introduced under the brand name Femandren M by 1953.[15]
Society and culture[]
Brand names[]
Brand names of testosterone isobutyrate include Agovirin-Depot, Perandren M, Testocryst, and Virex-Cryst.[12][13][16][17] It has also been marketed in combination with estradiol benzoate under the brand names Femandren M and Folivirin.[7][8][9][10][11]
Availability[]
Testosterone isobutyrate is available only in the Czech Republic and Slovakia.[1][16] It was originally manufactured by the pharmaceutical company SPOFA[18] intermittently manufactured by Biotika,[1] and is now manufactured by BB Pharma.[19]
^Heresová J, Pobisová Z, Hampl R, Stárka L (December 1986). "Androgen administration to transsexual women. II. Hormonal changes". Exp. Clin. Endocrinol. 88 (2): 219–23. doi:10.1055/s-0029-1210600. PMID3556412.
^Hampl R, Hána V, Heresová J, Brzek A, Marek J, Stárka L (January 1989). "Srovnání vylucování trí v Ceskoslovensku registrovaných androgenů" [Comparison of the excretion of 3 androgens registered in Czechoslovakia]. Sbornik Lekarsky (in Czech). 91 (1): 16–20. ISSN0036-5327. PMID2717876.
^ abMarek Josef; a kolektiv (14 May 2010). Farmakoterapie vnitřních nemocí: 4., zcela přepracované a doplněné vydání. Grada Publishing a.s. pp. 380–. ISBN978-80-247-9524-9. In addition, testosterone isobutyrate in FOLIVIRIN, Biotika, an injection containing 25 mg testosterone isobutyrate and 2.5 mg estradiol benzoate is available. It is applied every 4-6 weeks depending on the effect.
^Drescher H (April 1952). "Unsere Erfahrungen mit einer neuartigen Testosteron-isobutyrat-Kristallsuspension" [Experiences with a New Testosterone Isobutyrate Crystal Suspension]. Dtsch. Med. Wochenschr. (in German). 77 (14): 431–2. doi:10.1055/s-0028-1115985. PMID12988767.
^Ciba Symposium: 1953/57:Index. Ciba. 1953. p. 197. Femandren M. C'est le nom des nouvelles ampoules cristallines destinées au traitement associé œs- trogène-androgène. Elles renferment, sous forme de microcristaux, 2,5 mg de mono- benzoate d'œstradiol et 50 mg d'isobutyra- te de testostérone; elles sont indiquées pour traiter les cas où il convient d'administrer simultanément de l'hormone femelle et de l'hormone mâle et où il importe aussi d'obtenir un effet prolongé, par exemple lors de symptômes d'insuffisance à la ménopause ou après castration. L'effet d'une injection se prolonge pendant 3-6 semaines.
Anabolic steroids (e.g., testosterone and esters, methyltestosterone, metandienone (methandrostenolone), nandrolone and esters, many others; via estrogenic metabolites)