Urology Book

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5a-Reductase Inhibitor

Aka: 5a-Reductase Inhibitor, Finasteride, Proscar, Propecia, Dutasteride, Duagen
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  1. Indications
    1. Benign Prostatic Hyperplasia
      1. BPH-Associated Gross Hematuria
      2. Large Prostate size >40 ml (see PSA to estimate Prostate size)
    2. Androgenic Alopecia in males (Finasteride)
      1. Adjunct to hair transplantation
  2. Mechanism
    1. Inhibits Testosterone to Dihydrotestosterone conversion
      1. Competitive inhibition of enzyme 5a-reductase
      2. Finasteride inhibits Type II 5a reductase
      3. Dutasteride inhibits both Type I and II 5a reductase
    2. Reduces volume of Prostate
    3. Improves urine blood flow
  3. Dosing
    1. Alopecia
      1. Finasteride 1 mg PO qd
    2. Benign Prostatic Hyperplasia
      1. Finasteride 5 mg PO qd ($63 per month)
  4. Advantages: Finasteride
    1. Alopecia
      1. Increases Hair Growth and reduces Hair Loss
      2. Effective on vertex and anterior mid-scalp
      3. Side effects uncommon
    2. Benign Prostatic Hyperplasia
      1. May be more effective in men with large Prostate
  5. Disadvantages: Finasteride
    1. Alopecia
      1. Improvements take 6-12 months
      2. Any benefits are lost when medication is stopped
      3. Expensive (Pharmacist's cost: $50/month or $600/year)
    2. Benign Prostatic Hyperplasia
      1. Increased urine flow not evident for 6-12 months
      2. Mediocre effects on obstructive symptoms and urine flow (better in Prostate size >40 ml)
        1. Less effective than alpha blockers (e.g. Hytrin)
        2. Less effective than surgery
        3. Only as effective as Saw Palmetto
      3. Highly effective in reducing BPH-related Gross Hematuria (80%)
        1. Kearney (2002) J Urol 167:2489-91
  6. Adverse Effects
    1. Decreased Libido or Erectile Dysfunction (2%)
    2. Lowers Prostate Specific Antigen (PSA) Values by 30-50%
      1. Obtain PSA baseline prior to starting Finasteride
      2. Double the actual PSA to determine work-up
      3. Obtain baseline Digital Rectal Exam
    3. Longterm use associated with high grade Prostate Cancer
      1. Thompson (2003) N Engl J Med 349:215-24
  7. References
    1. (1992) Med Lett Drugs Ther 34:83
    2. Nickel (1996) CMAJ 155:1251-9
    3. Guess (1996) J Urol 155:3-9
Medication Costs
FINASTERIDE (on 2/10/2012 at Target.com)
FINASTERIDE 5 MG Tablet #30 for $9.00 ($0.30/unit)
Finasteride (on 2/9/2012 at DrugStore.com)
Finasteride 5mg Tablets #30 for $39.99 ($1.33/unit)
Proscar (on 2/9/2012 at DrugStore.com)
Proscar 5mg Tablets #30 for $120.79 ($4.03/unit)
Propecia (on 2/9/2012 at DrugStore.com)
Propecia 1mg Tablets #90 for $214.99 ($2.39/unit)
FPNotebook does not benefit financially from showing this medication data or their pharmacy links. This information is provided only to help medical providers and their patients see relative costs. Insurance plans negotiate lower medication prices with suppliers. Prices shown here are out of pocket, non-negotiated rates. See Needy Meds for financial assistance information.

Finasteride (C0060389)

Definition (MSH) An orally active 3-OXO-5-ALPHA-STEROID 4-DEHYDROGENASE inhibitor. It is used as a surgical alternative for treatment of benign PROSTATIC HYPERPLASIA.
Definition (CSP) orally active testosterone 5-alpha reductase inhibitor, used as an alternative to surgery for treatment of benign prostatic hyperplasia.
Definition (NCI) A drug used to reduce the amount of male hormone (testosterone) produced by the body.
Definition (PDQ) A synthetic 4-azasteroid compound. Finasteride competitively binds to and inhibits steroid type II 5-alpha-reductase in the prostate gland, liver, and skin, thereby interfering with the enzymatic conversion of testosterone to 5-dihydrotestosterone (DHT) and reducing serum DHT levels. The reduction in serum DHT levels results in diminished stimulation of androgen receptors in the nuclei of prostate cells and, so, diminished prostate cell proliferation. Check for "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=41096&idtype=1" active clinical trials or "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=41096&idtype=1&closed=1" closed clinical trials using this agent. ("http://nciterms.nci.nih.gov:80/NCIBrowser/ConceptReport.jsp?dictionary=NCI_Thesaurus&code=C1099" NCI Thesaurus)
Definition (NCI) A synthetic 4-azasteroid compound. Finasteride competitively binds to and inhibits steroid type II 5-alpha-reductase in the prostate gland, liver, and skin, thereby interfering with the enzymatic conversion of testosterone to 5-dihydrotestosterone (DHT) and reducing serum DHT levels. The reduction in serum DHT levels results in diminished stimulation of androgen receptors in the nuclei of prostate cells and, so, diminished prostate cell proliferation.
Concepts Steroid (T110) , Pharmacologic Substance (T121) , Hormone (T125)
MSH D018120
SnomedCT 109035006, 386963006
English Finasteride, 4-Azaandrost-1-ene-17-carboxamide, N-(1,1-dimethylethyl)-3-oxo-, (5alpha,17beta)-, (5alpha,17beta)-N-(1,1-Dimethylethyl)-3-oxo-4-azaandrost-1-ene-17-carboxamide, finasteride, finasteride (medication), FINASTERIDE, Finasteride [Chemical/Ingredient], finasteride products, Finasteride (product), Finasteride (substance)
Swedish Finasterid
Czech finasterid
Finnish Finasteridi
Russian FINASTERID, ФИНАСТЕРИД
Japanese フィナステリド
Polish Finasteryd
Spanish finasterida (producto), finasterida (sustancia), finasterida, Finasterida, Finasteride
French Finastéride
German Finasterid
Italian Finasteride
Portuguese Finasterida, Finasteride
Sources
Derived from the NIH UMLS (Unified Medical Language System)


Proscar (C0678149)

Concepts Steroid (T110) , Pharmacologic Substance (T121)
MSH D018120
English finasteride (Proscar), proscar, Proscar, Cahill May Roberts Brand of Finasteride, MSD Chibropharm Brand of Finasteride, Merck Brand 2 of Finasteride, Merck Frosst Brand 2 of Finasteride, Merck Sharp & Dhome Brand 2 of Finasteride
Sources
Derived from the NIH UMLS (Unified Medical Language System)


Propecia (C0722858)

Concepts Steroid (T110) , Pharmacologic Substance (T121)
MSH D018120
English finasteride (Propecia), propecia, propecias, Propecia, Propeshia, MSD Brand of Finasteride, Merck Brand 1 of Finasteride, Merck Frosst Brand 1 of Finasteride, Merck Sharp & Dohme Brand 1 of Finasteride
Sources
Derived from the NIH UMLS (Unified Medical Language System)


Dutasteride (C0754659)

Definition (NCI) A drug used to treat symptoms of an enlarged prostate gland. It is being studied in the treatment of male hair loss and prostate cancer. Avodart blocks enzymes the body needs to make male sex hormones. It is a type of 5-alpha reductase inhibitor.
Definition (PDQ) A synthetic 4-azasteroid compound. Dutasteride competitively and specifically binds to isoenzymes 1 and 2 of 5-alpha-reductase, forming stable enzyme complexes and inhibiting the conversion of testosterone to 5-alpha-dihydrotestosterone (DHT); the reduction in DHT activity may mitigate or prevent enlargement of the prostate gland. The type 2 5-alpha-reductase isoenzyme is primarily active in the reproductive tissues, while the type 1 isoenzyme is also active in skin and the liver. Check for "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=479183&idtype=1" active clinical trials or "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=479183&idtype=1&closed=1" closed clinical trials using this agent. ("http://nciterms.nci.nih.gov:80/NCIBrowser/ConceptReport.jsp?dictionary=NCI_Thesaurus&code=C47503" NCI Thesaurus)
Definition (NCI) A synthetic 4-azasteroid compound. Dutasteride competitively and specifically binds to isoenzymes 1 and 2 of 5 alpha-reductase, forming stable enzyme complexes and inhibiting the conversion of testosterone to 5 alpha-dihydrotestosterone (DHT); the reduction in DHT activity may mitigate or prevent enlargement of the prostate gland. The type 2 5 alpha-reductase isoenzyme is primarily active in the reproductive tissues, while the type 1 isoenzyme is also active in skin and the liver.
Concepts Steroid (T110) , Pharmacologic Substance (T121)
MSH C108373
SnomedCT 385570006, 385572003, 408009000
English DUTASTERIDE @ @ UNIDENTIFIED, DUTASTERIDE UNIDENTIFIED, alpha,alpha,alpha,alpha',alpha',alpha'-Hexafluoro-3-oxo-4-aza-5alpha-androst-1-ene-17beta-carboxy-2',5'-xylidide, Avolve,(5alpha,17beta)-N-(2,5-Bis(trifluoromethyl)phenyl)-3-oxo-4-azaandrost-1-ene-17-carboxamide, 17beta-N-(2,5-bis(trifluoromethyl))phenyl-carbamoyl-4-aza-5alpha-androst-1-en-3-one, dutasteride (medication), DUTASTERIDE, dutasteride [Chemical/Ingredient], Dutasteride, Dutasteride (product), Dutasteride (substance), dutasteride
Spanish Dutasteride (product), Dutasteride, dutasterida (producto), dutasterida (sustancia), dutasterida
Sources
Derived from the NIH UMLS (Unified Medical Language System)


5-alpha Reductase Inhibitor [EPC] (C1318898)

Definition (NCI) A substance that blocks an enzyme needed by the body to make dihydrotestosterone (a male sex hormone made from testosterone). Dihydrotestosterone can cause the prostate to grow. 5-alpha reductase inhibitors are used to shrink an enlarged prostate gland and to improve the flow of urine in a condition called benign prostatic hyperplasia (BPH). A 5-alpha reductase inhibitor is a type of enzyme inhibitor.
Definition (NCI) Substances that inhibit 5-alpha-Reductase, an enzyme that metabolizes testosterone to dihydrotestosterone, and can reduce prostate size.
Concepts Organic Chemical (T109) , Pharmacologic Substance (T121)
SnomedCT 406757009
English 5-alpha Reductase Inhibitor, 5-alpha Reductase Inhibitor [EPC], 5 alpha inhibitors reductase, 5-alpha reductase inhibitor, Testosterone 5-alpha reductase inhibitor, Type II 5-alpha reductase inhibitor, 5-Alfa reductase inhibitor, 5-Alpha reductase inhibitor (substance), 5-Alpha reductase inhibitor, 5 Alpha-Reductase Inhibitor, 5 Alpha-reductase Inhibitors
Spanish inhibidor de la 5-alfa-reductasa (sustancia), inhibidor de la 5-alfa-reductasa
Sources
Derived from the NIH UMLS (Unified Medical Language System)


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