Ketaconazole side effects

[ChessMaster3000]

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I know that ketoconazole causes gynecomastia and amenorrhea b/c it's an "anti-androgen". My question is, how does it being an antiandrogen cause those side effects? Is the result of an increase in the estrogen:androgen ratio?

 

[Transposony]

It blocks 17,20-lyase aka 17,20-desmolase which converts 17-hydroxypregnenolone and 17-hydroxyprogesterone to DHEA and androstenedione, respectively.

 

[Etorphine]

It blocks 17,20-lyase aka 17,20-desmolase which converts 17-hydroxypregnenolone and 17-hydroxyprogesterone to DHEA and androstenedione, respectively.

side note. also is a P450 inhibitor

 

[MudPhud20XX]

But isn't gynecomastia the result of too much estrogen? Ketoconazole blocks desmolase that converts cholesterol to pregnenolone, which is really the starting material for adrenal steroid synthesis such as aldosterone, cortisol, testosterone, and estradiol.

My understanding is that estradiol is synthesized in ovaries by aromatase which converts testosterone to estradiol (a type of estrogen).

So if you block this pathway with ketoconazole, you wouldn't get testosterone, which is the precursor for estradiol, right?

So how do you explain gynecomastia? What am I missing here?

 

[Myxedema]

You are correct, but what ketoconazole actually does is that it changes E2/T ratio (link).

 

[ChessMaster3000]

You are correct, but what ketoconazole actually does is that it changes E2/T ratio (link).

by extension we can say that other androgenic side effects like hirsutism are also a result of this ratio being increased.

 

[Myxedema]

by extension we can say that other androgenic side effects like hirsutism are also a result of this ratio being increased.

Hirsutism occurs as a result of androgen excess. Ketoconazole does not cause hirsutism; it can be used in the treatment of hirsutism.

 

[ChessMaster3000]

Hirsutism occurs as a result of androgen excess. Ketoconazole does not cause hirsutism; it can be used in the treatment of hirsutism.

Right, I was just saying in another situation (PCOS), not in the case of ketaconazole. sorry for the confusion