Androgen Drugs – Flashcards
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What drugs have androgenic actions?
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Testosterone Methyltestosterone Oxymetholone
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Testosterone is converted to what?
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DHT which is the active form
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how is testosterone transported in the blood?
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SHBG -- protein bound
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What places make testosterone
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MOST 95% in leydig cells of testes rest is in the adrenal glands (Zona reticularis) and some in the ovary
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Testosterone is made from what ?
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Progesterone and DHEA
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how is testosterone replacement admin?
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I.M. NOT by oral b/c of significant first pass effect
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What are testosterones used for replacement?
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Testosterone Proprionate (short acting) Testosterone enanthate Testosterone cypionate (long acting)
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how is methyltestosterone admin?
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oral or buccal admin
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What is methyltestosterone used for?
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Hypogonadism -- replacement therapy Delayed puberty Breast cancer --- antagonist vs. estrogen
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how is oxymetholone admin?
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Oral
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What was oxymetholone used for?
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anemia --- but been replaced by EPO androgen replacement therapy
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What are the uses of androgens?
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Replacement therapy Stimulates Erythropoiesis ---- more RBCs Short stature --- it will increase the length of long bone but can increase closure of plate Athletic performance b/c of anabolic functions
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Side effects of Androgens
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Women ---Virilization (hirsutism, enlarged clitoris, deepened voice) and menstrual irregularity + liver probs Men == Impotence, decreased spermatogenesis, gynecomastia, liver probs (jaundice, increases liver enzymes, risk for cancer) + psychotic episodes Children == early epiphyseal closure & if during utero abnormal sex development and also abnormal sex maturation
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What are the antiandrogens?
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Ketaconazole Spironolactone Finasteride Cyproterone acetate Flutamide
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MOA of Ketoconazole
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antifungal agent that is involved in blocking gonadal and adrenal steroid synthesis blocks p450 enzymes involved in adrogen synthesis lecture says competitive antagonist of cholesterol esterase the rate limiting step in androgen synth
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What antiandrogen drug also interferes with synthesis of other steroids?
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Ketoconazole
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What antiandrogen inhibits p450?
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Ketoconazole
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Use of Ketoconazole
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Used for advanced prostate cancer that is RESISTANT to first line antiandrogen drugs
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MOA of spironolactone
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K+ sparing Diurectic that is an aldosterone antagonist also INHIBITS androgen binding to Androgen receptor lecture says competitive antagonist of cholesterol esterase the rate limiting step in androgen synth
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What is Spironolactone used for besides diuretic?
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to TX hirsutism
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MOA of Finasteride
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Blocks 5a-reductase
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What enzyme converts Testosterone to DHT?
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5alpha-reductase
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What tissues depend on DHT and not testosterone for stimulation?
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Prostate cells and hair follicles
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What is Finasteride used for?
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BPH !!! and for hair loss in men [lower doses] (male pattern baldness) as well as early stages of prostate cancer
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What does finasteride NOT cause that other antiandrogens do?
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impotence, infertility, and loss of libido
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What antiandrogen drug does NOT cause impotence, infertility, or loss of libido?
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Finasteride
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Why does finasteride not cause infertility/loss of libido?
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Because it does NOT interfere with the actions of testosterone
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MOA of Cyproterone acetate
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competitive antagonist of DHT-androgen receptor binding has progesterone like activity ---> suppresses GnRH secretion
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MOA of Flutamide
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Pure competitive antiandrogen to androgen receptors and it BLOCKS negative feedback loops for testosterone --> temporary increase in GnRH and actions of testosterone
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Use of Flutamide
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used for advanced prostate cancer
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What drug is best for BPH?
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Finasteride
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Adverse effects of Flutamide
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gynecomastia hot flushes impotence
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Use of Antiandrogens
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Prostatic hyperplasia & cancer Acne Male Pattern baldness Virilization syndromes Precocious puberty Inhibition of sex drive -- [sex offenders?]
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MOA of leuprolide
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GnRH agonist and agonist of LH receptor used for advanced prostate cancer
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What drugs are used for prostate cancer?
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Flutamide Leuprolide & other hi-potency GnRH analogs -- Histrelin, Narfarelin (nasal) -- chronic admin will cause downregulation of GnRH receptors so less LH/FSH made and thus less testo DES -- nonsteroidal estrogen that antagonizes physiologic effects of testo GnRH anatagonists --- abarelix and degarelix
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What drug did they think was a male contraceptive?
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Gossypol
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adverse effects of Leuprolide
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HA Light headedness Nausea Hypogonadism with continuous treatment
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How do GnRH AGONISTs treat prostate cancer?
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initially causes agonistic action at the GnRH receptor (give flutamide to block these effects), but within several weeks, testosterone production falls to low levels. Chronic administration --> decreased gonadotropins and end-product hormones
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What drugs block androgen receptor?
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Flutamide Spironolactone Cyproterone (DHT)
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What are the clinical uses of testosterone
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Androgen replacement for hypogonadism Stimulate RBC production in anemias promote Weight gain in pts. with wasting syndromes (like AIDS)
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Why are testosterones abused by athletes?
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because of the anabolic effects that it also has.... increas muscle size and strength and it can increase RBC
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What is testosterone propionate used for?
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hypogonadism delayed puberty receptor positive breast cancer
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What is testosterone enanthate used for?
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hypogonadism delayed puberty metastatic breast cancer -- mets to bone
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What is testosterone cypionate used for?
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treatment of hypogonadism -- long acting
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What is fluoxymesterone used for?
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treatment of hypogonadism in men and breast cancer in women
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What is oxandrolone used for?
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increased ratio of anabolic-to-androgenic activity -- abuse potential -- can cause cholestatic jaundice and liver toxicity
