Bayer Proviron 25 Mg.
Manufacturer: Bayer Schering Turkey
Pack: 20 tabs (25 mg/tab)
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.
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.
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 1α-methyl-androsterone, which - in conjugated form - accounts for 55 - 70 % of renally excreted metabolites. The ratio of conjugated main metabolite glucuronide to sulfate detected in urine was about 12:1. As a further metabolite 1α-methyl-5α-androstane-3α,17β-diol has been recognized, which accounted for about 3 % of renally eliminated metabolites. Mesterolone was excreted in the form of metabolites. Within 7 days approximately 80% of the labelled doses were recovered in the urine and up to 13% in the faeces. Half of the labelled doses were excreted in the urine within 24 hours. The absolute bioavailability of mesterolone was determined to be about 3 % of the oral dose.