Finasteride


Generic Medicine Info
Indications and Dosage
Oral
Male pattern baldness
Adult: 1 mg once daily for at least 3 months. Use continuously to sustain benefit.

Oral
Benign prostatic hyperplasia
Adult: As monotherapy or in combination with doxazosin: 5 mg once daily for at least 6 months.
Administration
May be taken with or without food.
Contraindications
Women. Children. Pregnancy and lactation.
Special Precautions
Patient with large residual urine and/or severely decreased urinary flow. Not indicated for the prevention of prostate cancer. Hepatic impairment.
Adverse Reactions
Significant: Breast cancer, mood alterations (e.g. depressed mood, depression and rarely, suicidal ideation).
Immune system disorders: Hypersensitivity reaction (e.g. angioedema, urticaria).
Investigations: Decreased volume of ejaculate.
Reproductive system and breast disorders: Impotence, decreased libido, ejaculation disorder, haematospermia, breast tenderness and enlargement, testicular pain, male infertility and/or poor seminal quality.
Skin and subcutaneous tissue disorders: Rash, pruritus.
Patient Counseling Information
Women of child-bearing potential or who are pregnant should not handle crushed or broken tab. Excreted in semen therefore use of condom is recommended.
Monitoring Parameters
Rule out other urological diseases (e.g. prostate cancer) before initiation of therapy. Perform digital rectal examination and other assessment for prostate cancer before and during therapy. Obtain new baseline prostate-specific antigen (PSA) level after ≥6 months of treatment then monitor periodically thereafter. Monitor for psychiatric symptoms, objective and subjective signs of relief of benign prostatic hyperplasia (e.g. improvement in urinary flow, reduction in symptoms of urgency, relief of difficulty in micturition).
Lab Interference
Decreases serum PSA level by approx 50% within 6 months of use.
Action
Description: Finasteride, a 4-azasteroid, is a competitive inhibitor of type II 5-α reductase. This results in the suppression of the conversion of testosterone to dihydrotestosterone, leading to significantly decreased serum dihydrotestosterone (DHT) levels. In male-pattern baldness, finasteride decreases scalp DHT levels found in hairy scalp thus increases hair regrowth and slows hair loss.
Duration: Prostate volume reverts to baseline within approx 3 months after stopping treatment (benign prostatic hyperplasia); reversal of effect within 12 months of stopping treatment (male-pattern baldness).
Pharmacokinetics:
Absorption: Bioavailability: Approx 63-80%. Time to peak plasma concentration: 1-2 hours.
Distribution: Crosses the blood-brain barrier and detected in the seminal fluid (small amounts). Volume of distribution: 76 L. Plasma protein binding: Approx 90%.
Metabolism: Extensively metabolised in the liver by CYP3A4 into 2 active metabolites.
Excretion: Via faeces (57%); urine (39%, as metabolites). Elimination half-life: Approx 5-6 hours.
Chemical Structure

Chemical Structure Image
Finasteride

Source: National Center for Biotechnology Information. PubChem Database. Finasteride, CID=57363, https://pubchem.ncbi.nlm.nih.gov/compound/Finasteride (accessed on Jan. 21, 2020)

Storage
Store below 30°C. Protect from light and moisture.
ATC Classification
D11AX10 - finasteride ; Belongs to the class of other dermatologicals.
G04CB01 - finasteride ; Belongs to the class of testosterone-5-alpha reductase inhibitors. Used in the treatment of benign prostatic hypertrophy.
References
Anon. Finasteride. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 29/01/2021.

Buckingham R (ed). Finasteride. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 29/01/2021.

Finasteride 1 mg Tablet, Film Coated (Accord Healthcare, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 29/01/2021.

Finasteride 1 mg Tablets (Dr Reddy’s Laboratories [UK] Ltd). MHRA. https://products.mhra.gov.uk/. Accessed 01/02/2021.

Finasteride 5 mg Tablet, Film Coated (Accord Healthcare, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 02/02/2021.

Finasteride 5 mg Tablets (Dr Reddy’s Laboratories [UK] Ltd). MHRA. https://products.mhra.gov.uk/. Accessed 29/01/2021.

Organon New Zealand Limited. Propecia 1 mg Film Coated Tablets data sheet 1 December 2020. Medsafe. http://www.medsafe.govt.nz/. Accessed 29/01/2021.

Proscar 5 mg Tablet (Merck Sharp & Dohme [Malaysia] Sdn. Bhd.). National Pharmaceutical Regulatory Agency - Ministry of Health Malaysia. https://www.npra.gov.my/. Accessed 02/02/2021.

Rex Medical Limited. Ricit 5 mg Film Coated Tablets data sheet 5 May 2017. Medsafe. http://www.medsafe.govt.nz/. Accessed 02/02/2021.

Disclaimer: This information is independently developed by MIMS based on Finasteride from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2021 MIMS. All rights reserved. Powered by MIMS.com
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