Proviron

Country: Australia

Language: English

Source: Department of Health (Therapeutic Goods Administration)

Active ingredient:

Mesterolone

Available from:

Bayer Australia Ltd

Class:

Medicine Registered

Summary of Product characteristics

PRODUCT INFORMATION 

PROVIRON
®

NAME OF THE MEDICINE 

Mesterolone is a white to yellowish crystalline powder and is
practically insoluble 
in water
.

The chemical name for mesterolone is 17 beta-Hydroxy-1 alpha-methyl-5
alpha-
androstan-3-one and has the following structural formula: 

O
CH
3
CH
3
OH
H
H
H
CH
3
H

Molecular formula 
C20H32O2 
Molecular weight 
304.47 
Melting point  
205 - 211
°C 
CAS Number 
001424-00-6 

DESCRIPTION 

Proviron is a hormonal preparation and contains 25 mg mesterolone.  

Each small white tablet contains mesterolone 25 mg and the
excipients: lactose, 
starch-maize, povidone, methyl hydroxybenzoate, propyl hydroxybenzoate
and 
magnesium stearate.  

PHARMACOLOGY 

PHARMACODYNAMICS 

1
Mesterolone (Proviron) has androgenic properties. Early studies
suggested oral 
mesterolone did not usually suppress gonadotrophins or endogenous 
testosterone production. A later single dose study suggests there may
be a 
central suppression effect at doses of 75-100 mg daily.  

PHARMACOKINETICS 

Following oral ingestion mesterolone is rapidly absorbed. In a study
in 18 men 
the intake of Proviron 25 mg generated maximum serum drug levels of
3.1 ± 1.1 
ng/mL after 1.6 ± 0.6 hours. Thereafter, drug levels in serum
decrease with a 
terminal half-life of 12 - 13 hours. Mesterolone is bound to serum
proteins by 98 
%. Binding to albumin accounts for 40 % and binding to SHBG (sex
hormone 
binding globulin) to 58 %. 
Mesterolone is rapidly metabolised. The metabolic clearance rate from
serum 
accounts for 4.4 ± 1.6 mL·min-1·kg-1. Renal excretion of unchanged
drug has not 
been detected. In a study of C14 labelled mesterolone in two men, up
to 2% of 
mesterolone was excreted as the conjugated form in the urine. The
main 
metabolite has been identified as 1
α-methyl-androsterone, which - in conjugated 
form - accounts for 55 - 70 % of renally excreted metabolites.  The
ratio of 
conjugated mai