Metenolone

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Metenolone
Clinical data
Trade names Primobolan, Nibal (as metenolone acetate); Primobolan Depot, Nibal Injection (as metenolone enanthate)
Other names Methenolone; Methylandrostenolone; 1-Methyl-δ1-4,5α-dihydrotestosterone; 1-Methyl-δ1-DHT; 1-Methyl-5α-androst-1-en-17β-ol-3-one
AHFS/Drugs.com International Drug Names
Routes ofadministration By mouth (as metenolone acetate), intramuscular injection (as metenolone enanthate)
Drug class Androgen; Anabolic steroid
ATC code
Legal status
Legal status
Identifiers
  • (5S,8R,9S,10S,13S,14S,17S)-17-hydroxy-1,10,13-trimethyl-4,5,6,7,8,9,11,12,14,15,16,17-dodecahydrocyclopenta[a]phenanthren-3-one
CAS Number
PubChem CID
ChemSpider
UNII
CompTox Dashboard (EPA)
ECHA InfoCard 100.005.285
Chemical and physical data
Formula C20H30O2
Molar mass 302.458 g·mol−1
3D model (JSmol)
  • O=C2\C=C(\C)[C@@]3([C@H]1CC[C@@]4([C@@H](O)CC[C@H]4[C@@H]1CC[C@H]3C2)C)C
  • InChI=1S/C20H30O2/c1-12-10-14(21)11-13-4-5-15-16-6-7-18(22)19(16,2)9-8-17(15)20(12,13)3/h10,13,15-18,22H,4-9,11H2,1-3H3/t13-,15-,16-,17-,18-,19-,20-/m0/s1 Y
  • Key:ANJQEDFWRSLVBR-VHUDCFPWSA-N Y

Metenolone, or methenolone, is an androgen and anabolic steroid (AAS) which is used in the form of esters such as metenolone acetate (brand name Primobolan, Nibal) and metenolone enanthate (brand name Primobolan Depot, Nibal Injection).[1][2][3][4][5] Metenolone esters are used mainly in the treatment of anemia due to bone marrow failure.[6] Metenolone acetate is taken by mouth, while metenolone enanthate is given by injection into muscle.[5]

Side effects of metenolone esters include symptoms of masculinization like acne, increased hair growth, voice changes, and increased sexual desire.[5] Metenolone esters are synthetic androgens and anabolic steroids and hence are agonists of the androgen receptor (AR), the biological target of androgens like testosterone and dihydrotestosterone (DHT).[5][7] They have moderate anabolic effects and weak androgenic effects, as well as no estrogenic effects or risk of liver damage.[5][7] Metenolone esters are androgen esters and prodrugs of metenolone in the body.[5]

Metenolone esters were introduced for medical use in the early 1960s.[5] In addition to their medical use, metenolone esters are used to improve physique and performance.[5] The drugs are controlled substances in many countries and so non-medical use is generally illicit.[5] They have mostly been discontinued for medical use and have limited availability.[4][5]

Medical uses[edit]

Metenolone, as its esters, is used almost exclusively in the treatment of anemia due to bone marrow failure.[6] It has also been used to treat wasting syndromes due to major surgery, infection, long-term corticosteroid therapy, malnutrition, or other causes.[5] It has also been used to treat osteoporosis and sarcopenia, to inhibit the natural loss of muscle mass with aging, and to promote weight gain in underweight premature infants and children.[5]

Side effects[edit]

Side effects of metenolone and its esters include virilization among others.[5]

Pharmacology[edit]

Pharmacodynamics[edit]

Androgenic vs. anabolic activity
of androgens/anabolic steroids
Medication Ratioa
Testosterone ~1:1
Androstanolone (DHT) ~1:1
Methyltestosterone ~1:1
Methandriol ~1:1
Fluoxymesterone 1:1–1:15
Metandienone 1:1–1:8
Drostanolone 1:3–1:4
Metenolone 1:2–1:30
Oxymetholone 1:2–1:9
Oxandrolone 1:3–1:13
Stanozolol 1:1–1:30
Nandrolone 1:3–1:16
Ethylestrenol 1:2–1:19
Norethandrolone 1:1–1:20
Notes: In rodents. Footnotes: a = Ratio of androgenic to anabolic activity. Sources: See template.

Due to its double bond between the C1 and C2 positions, metenolone is resistant to metabolism by 3α-hydroxysteroid dehydrogenase (3α-HSD).[5] As such, unlike DHT and the closely related DHT derivatives mestanolone (17α-methyl-DHT) and mesterolone (1α-methyl-DHT), metenolone has considerable anabolic effects.[5]

Pharmacokinetics[edit]

Metenolone has very low affinity for human serum sex hormone-binding globulin (SHBG), about 16% of that of testosterone and 3% of that of DHT.[8]

Chemistry[edit]

Metenolone, also known as 1-methyl-4,5α-dihydro-δ1-testosterone (1-methyl-δ1-DHT) or as 1-methyl-5α-androst-1-en-17β-ol-3-one, is a synthetic androstane steroid and derivative of dihydrotestosterone (DHT).[1][2][5] A closely related AAS is mesterolone (1α-methyl-DHT).[1][2][5]

Society and culture[edit]

Generic names[edit]

Metenolone is the generic name of the drug and its INN, while methenolone is its BAN.[1][2][3][4] It has also been referred to as methylandrostenolone.[2][4] This synonym should not be confused with methandrostenolone, which is another name for a different AAS known as metandienone.[9]

Doping in sports[edit]

Metenolone and its esters are banned from use in sports governed by the World Anti-Doping Agency.[10] The NBA and NBPA also banned the use of metenolone and its esters under the Anti-Drug Program. There are known cases of doping in sports with metenolone esters by professional athletes.

References[edit]

  1. ^ a b c d J. Elks (14 November 2014). The Dictionary of Drugs: Chemical Data: Chemical Data, Structures and Bibliographies. Springer. pp. 784–. ISBN 978-1-4757-2085-3.
  2. ^ a b c d e Index Nominum 2000: International Drug Directory. Taylor & Francis. 2000. pp. 659–660. ISBN 978-3-88763-075-1.
  3. ^ a b I.K. Morton; Judith M. Hall (6 December 2012). Concise Dictionary of Pharmacological Agents: Properties and Synonyms. Springer Science & Business Media. pp. 178–. ISBN 978-94-011-4439-1.
  4. ^ a b c d "List of Androgens and anabolic steroids".
  5. ^ a b c d e f g h i j k l m n o p q William Llewellyn (2011). Anabolics. Molecular Nutrition Llc. pp. 625–, 633–. ISBN 978-0-9828280-1-4.
  6. ^ a b J. Larry Jameson; Leslie J. De Groot (25 February 2015). Endocrinology: Adult and Pediatric E-Book. Elsevier Health Sciences. pp. 2388–. ISBN 978-0-323-32195-2.
  7. ^ a b Kicman AT (2008). "Pharmacology of anabolic steroids". Br. J. Pharmacol. 154 (3): 502–21. doi:10.1038/bjp.2008.165. PMC 2439524. PMID 18500378.
  8. ^ Saartok T, Dahlberg E, Gustafsson JA (1984). "Relative binding affinity of anabolic-androgenic steroids: comparison of the binding to the androgen receptors in skeletal muscle and in prostate, as well as to sex hormone-binding globulin". Endocrinology. 114 (6): 2100–6. doi:10.1210/endo-114-6-2100. PMID 6539197.
  9. ^ Index Nominum 2000: International Drug Directory. Taylor & Francis. 2000. p. 660. ISBN 978-3-88763-075-1.
  10. ^ "The World Anti-Doping Code: The 2012 Prohibited List" (PDF). World Anti-Doping Agency. Archived from the original (PDF) on 2012-05-13. Retrieved 2012-05-10.

External links[edit]