Finasteride (Lexi-Drugs)

Special Alerts
  Finasteride Safety AlertFebruary 2019

(fi NAS teer ide)

Brand Names: US

Propecia; Proscar

Brand Names: Canada

ACH-Finasteride; ACT Finasteride; APO-Finasteride; Auro-Finasteride; DOM-Finasteride; JAMP-Finasteride; MINT-Finasteride; MYLAN-Finasteride HG [DSC]; MYLAN-Finasteride [DSC]; PMS-Finasteride; Propecia; Proscar; RAN-Finasteride; RATIO-Finasteride [DSC]; RIVA-Finasteride; SANDOZ Finasteride; SANDOZ Finasteride A; TEVA-Finasteride; VAN-Finasteride

Pharmacologic Category

5 Alpha-Reductase Inhibitor

Dosing: Adult

Benign prostatic hyperplasia (Proscar): Males: Oral: 5 mg once daily (either as a single agent or in combination with doxazosin); early responses may occur although 6 months of treatment is usually needed to assess benefit.

Hirsutism (off-label use): Females: Oral: 2.5 to 5 mg once daily; assess response at 6-month intervals before adjusting dose, adding additional agents, or switching to alternative therapy (Endocrine Society [Martin 2018]).

Male pattern baldness (Propecia): Males: Oral: 1 mg once daily; may take 3 months or longer of daily use for observed benefit; continued use is recommended to sustain benefit.

Dosing: Geriatric

Refer to adult dosing.

Dosing: Renal Impairment: Adult

No dosage adjustment is necessary.

Dosing: Hepatic Impairment: Adult

There are no dosage adjustments provided in the manufacturer’s labeling. Use with caution (finasteride is metabolized extensively in the liver)

Use: Labeled Indications

Androgenetic alopecia (Propecia): Treatment of male pattern hair loss in men only.

Limitations of use: Efficacy in bitemporal recession has not been established; not indicated for use in women.

Benign prostatic hyperplasia (Proscar): Treatment (monotherapy) of symptomatic benign prostatic hyperplasia (BPH) to improve symptoms, reduce the risk of acute urinary retention, and to reduce the risk of need for BPH-related surgery); used in combination with an alpha-blocker (doxazosin) to reduce the risk of symptomatic progression.

Limitations of use: Not approved for the prevention of prostate cancer.

Use: Off-Label: Adult

  HirsutismLevel of Evidence [B, G]

Data from a systematic review and network meta-analysis of published randomized trials of adult females with hirsutism (including idiopathic hirsutism and hirsutism in women with polycystic ovary syndrome or nonclassic congenital adrenal hyperplasia) support the use of finasteride for treatment of hirsutism Ref. Additional trials may be necessary to further define the role of finasteride for the treatment of this condition.

Based on the Evaluation and Treatment of Hirsutism in Premenopausal Women: An Endocrine Society Clinical Practice guideline, finasteride is effective and may be considered among other antiandrogens in the management of this condition. Finasteride may be considered for initial therapy, either as monotherapy in women who are not at risk for becoming pregnant, or in combination with an oral contraceptive in select women with severe hirsutism causing distress and/or a prior history of inadequate response to oral contraceptive therapy. Finasteride may also be considered for add-on therapy in women who fail to achieve a satisfactory response to initial oral contraceptive monotherapy RefAccess Full Off-Label Monograph

Level of Evidence Definitions
  Level of Evidence Scale
Use: Unsupported: Adult
Prostate cancer prevention

The effects of finasteride on prevention of prostate cancer were evaluated in a large, randomized, placebo controlled study in men considered at increased risk for prostate cancer, and a statistically significant increase in the incidence of higher grade prostate cancer (Gleason score ≥7) was found in men who received finasteride (Thompson 2003; Thompson 2013).

Clinical Practice Guidelines


Endocrine Society, “The Evaluation and Treatment of Hirsutism in Premenopausal Women: An Endocrine Society Clinical Practice Guideline,” 2018

Administration: Oral

May be administered with or without meals. Females of childbearing age should not touch or handle crushed or broken tablets.

Hazardous Drugs Handling Considerations

Hazardous agent (NIOSH 2016 [group 3]).

Use appropriate precautions for receiving, handling, administration, and disposal. Gloves (single) should be worn during receiving, unpacking, and placing in storage. NIOSH recommends single gloving for administration of intact tablets or capsules (NIOSH 2016). Assess risk to determine appropriate containment strategy (USP-NF 2017).


Propecia: Store at 15°C to 30°C (59°F to 86°F). Keep container tightly closed and protect from moisture.

Proscar: Store below 30°C (86°F). Protect from light. Keep container tightly closed.

Medication Patient Education with HCAHPS Considerations

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Patient may experience sexual dysfunction, loss of strength and energy, or decreased libido. Have patient report immediately to prescriber enlarged breasts, severe dizziness, passing out, depression, testicle pain, lump in breast, breast soreness or pain, or nipple discharge (HCAHPS).

• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.

Medication Safety Issues
  Sound-alike/look-alike issues:

Hypersensitivity to finasteride or any component of the formulation; pregnancy or women of childbearing potential


Disease-related concerns:

• Diminished urinary flow: Carefully monitor patients with a large residual urinary volume or severely diminished urinary flow for obstructive uropathy; these patients may not be candidates for finasteride therapy.

• Hepatic impairment: Use with caution in patients with hepatic impairment; finasteride is extensively metabolized in the liver.

• Prostate cancer: When compared to placebo, 5-alpha-reductase inhibitors (5-ARIs) have been associated with an increase in the incidence of high-grade prostate cancers; 5-ARIs are not approved in the US or Canada for the prevention of prostate cancer.

Special handling:

• Females/pregnancy: Active ingredient of crushed or broken tablets can be absorbed through the skin; unbroken tablets are coated which prevents contact with the active ingredient during normal handling. Pregnant females should avoid contact with crushed or broken tablets; finasteride may negatively impact fetal development.

Other warnings/precautions:

• Appropriate use: Other urological diseases (including prostate cancer) should be ruled out before initiating (in BPH management). Not indicated for use in pediatric patients.

• Duration of therapy: For BPH, a minimum of 6 months of treatment may be necessary to determine whether an individual will respond to finasteride; for male pattern hair loss, daily use for 3 months or longer may be required before benefit is observed (withdrawal of treatment leads to reversal of hair growth effect within 12 months).

• PSA monitoring: Reduces prostate specific antigen (PSA) concentration by ~50% within 6 months of treatment. To interpret serial PSAs, a new PSA baseline should be established ≥6 months after treatment initiation and PSA monitored periodically thereafter. A confirmed PSA increase while on this medication, even if within normal limits, may be associated with an increased risk for prostate cancer and should be evaluated. Finasteride does not interfere with free PSA levels.

Geriatric Considerations

Clearance of finasteride is decreased in the elderly, but no dosage reductions are necessary.

Pregnancy Risk Factor


Pregnancy Considerations

Use is contraindicated in females of childbearing potential.

Abnormalities of external male genitalia were reported in animal reproduction studies. Pregnant females are advised to avoid contact with crushed or broken tablets.

Adequate contraception is recommended if used off-label in the management hirsutism in females associated with PCOS (ACOG 194 2018).

Breast-Feeding Considerations

It is not known if finasteride is present in breast milk. Use is contraindicated in females of childbearing potential.

Adverse Reactions

Note: “Combination therapy” refers to finasteride and doxazosin.


Cardiovascular: Orthostatic hypotension (combination therapy 18%)

Central nervous system: Dizziness (combination therapy 23%; monotherapy 7%)

Endocrine & metabolic: Decreased libido (combination therapy 12%; monotherapy 2% to 10%)

Genitourinary: Impotence (combination therapy 23%; monotherapy 5% to 19%), ejaculatory disorder (combination therapy 14%; monotherapy <1% to 7%)

Neuromuscular & skeletal: Weakness (combination therapy 17%; monotherapy 5%)

1% to 10%:

Cardiovascular: Edema (combination therapy 3%; monotherapy 1%)

Central nervous system: Drowsiness (combination therapy 3%; monotherapy 2%)

Dermatologic: Skin rash (monotherapy 1%)

Endocrine & metabolic: Gynecomastia (monotherapy 1% to 2%)

Genitourinary: Decreased ejaculate volume (monotherapy 2% to 4%), breast tenderness (monotherapy ≤1%)

Respiratory: Dyspnea (combination therapy 2%; monotherapy 1%), rhinitis (combination therapy 2%; monotherapy 1%)

<1%, postmarketing, and/or case reports: Altered mental status, attempted suicide (Welk 2017), change in libido, decreased testicular size, depression, disturbed sleep, hypersensitivity (angioedema, facial swelling, pharyngeal edema, pruritus, skin rash, swelling of the lips, swollen tongue, urticaria), male infertility (temporary), malignant neoplasm of the male breast, prostate cancer – high grade, prostatitis, reduction in penile curvature, reduction in penile size, sexual disorder (may not be reversible with discontinuation), suicidal ideation (Welk 2017), testicular pain

Allergy and Idiosyncratic Reactions
Metabolism/Transport Effects

Substrate of CYP3A4 (minor); Note: Assignment of Major/Minor substrate status based on clinically relevant drug interaction potential

Drug Interactions 

There are no known significant interactions.

Test Interactions

PSA levels decrease in treated patients. After 6 months of therapy, PSA levels stabilize to a new baseline that is ~50% of pretreatment values. If following serial PSAs in a patient, re-establish a new baseline after ≥6 months of use.

Monitoring Parameters

To interpret serial PSAs, establish a new PSA baseline ≥6 months after treatment initiation and monitor PSA periodically thereafter. Objective and subjective signs of relief of benign prostatic hyperplasia, including improvement in urinary flow, reduction in symptoms of urgency, and relief of difficulty in micturition.

Advanced Practitioners Physical Assessment/Monitoring

For interpretation of serial PSAs, a new baseline should be established after 6 months of therapy. Any increase from the lowest PSA value should be evaluated as a possible signal of prostate cancer even if it is considered within normal limits. Assess for objective and subjective signs of relief of benign prostatic hyperplasia, including improvement in urinary flow, reduction in symptoms of urgency, and relief of difficulty in micturition.

Nursing Physical Assessment/Monitoring

Check ordered labs and report any abnormalities. Instruct pregnant women to avoid contact with crushed or broken tablets.

Dosage Forms: US

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Tablet, Oral:

Propecia: 1 mg

Proscar: 5 mg [contains fd&c blue #2 aluminum lake]

Generic: 1 mg, 5 mg

Dosage Forms: Canada

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Tablet, Oral:

Propecia: 1 mg

Proscar: 5 mg [contains FD&C BLUE #2 ALUMINUM LAKE]

Generic: 1 mg, 5 mg

Anatomic Therapeutic Chemical (ATC) Classification
  • D11AX10
  • G04CB01
Generic Available (US)


Pricing: US

Tablets (Finasteride Oral)

1 mg (per each): $2.43 – $2.48

5 mg (per each): $3.11 – $3.19

Tablets (Propecia Oral)

1 mg (per each): $4.14

Tablets (Proscar Oral)

5 mg (per each): $5.65

Disclaimer: A representative AWP (Average Wholesale Price) price or price range is provided as reference price only. A range is provided when more than one manufacturer’s AWP price is available and uses the low and high price reported by the manufacturers to determine the range. The pricing data should be used for benchmarking purposes only, and as such should not be used alone to set or adjudicate any prices for reimbursement or purchasing functions or considered to be an exact price for a single product and/or manufacturer. Medi-Span expressly disclaims all warranties of any kind or nature, whether express or implied, and assumes no liability with respect to accuracy of price or price range data published in its solutions. In no event shall Medi-Span be liable for special, indirect, incidental, or consequential damages arising from use of price or price range data. Pricing data is updated monthly.

Mechanism of Action

Finasteride competitively inhibits type II 5-alpha reductase, resulting in inhibition of the conversion of testosterone to dihydrotestosterone and markedly suppresses serum dihydrotestosterone levels


Duration: Dihydrotestosterone levels return to normal within 14 days of discontinuation of treatment; BPH: Prostate volume returns to baseline within ~3 months after discontinuation; Male pattern baldness: Reversal of increased hair count within 12 months

Distribution: Vdss: 76 L

Protein binding: ~90%

Metabolism: Hepatic (extensive) via CYP3A4; two active metabolites (<20% activity of finasteride)

Bioavailability: Mean: 5 mg: ~63%; 1 mg: 65% (not affected by food)

Half-life elimination, serum: 5 to 6 hours (range: 3 to 16 hours); Elderly (≥70 years): 8 hours (range: 6 to 15 hours)

Time to peak, serum: 1 to 2 hours

Excretion: Feces (57%) and urine (39%; as metabolites)

Pharmacodynamics/Kinetics: Additional Considerations

Renal function impairment: Urinary excretion of metabolites was decreased in patients with renal impairment. This decrease was associated with an increase in fecal excretion of metabolites. Plasma concentrations of metabolites were significantly higher in patients with renal impairment (based on a 60% increase in total radioactivity AUC).

Geriatric: Mean AUC0-24 increases 15%.

Local Anesthetic/Vasoconstrictor Precautions

No information available to require special precautions

Effects on Dental Treatment

No significant effects or complications reported

Effects on Bleeding

No information available to require special precautions

FDA Approval Date
June 19, 1992

<800> Hazardous Drugs—Handling in Healthcare Settings. United States Pharmacopeia and National Formulary (USP 40-NF 35). Rockville, MD: United States Pharmacopeia Convention; 2017:83-102.

American College of Obstetricians and Gynecologists. ACOG Practice Bulletin No. 194: Polycystic Ovary Syndrome. Obstet Gynecol. 2018;131(6):e157-e171. doi: 10.1097/AOG.0000000000002656.[PubMed 29794677]

Barrionuevo P, Nabhan M, Altavar O, et al. Treatment options for hirsutism: a systematic review and network meta-analysis. J Clin Endocrinol Metab. 2018. doi: 10.1210/jc.2017-02052.[PubMed 29522176]

Irwig MS, “Persistent Sexual Side Effects of Finasteride: Could They Be Permanent?” J Sex Med, 2012.[PubMed 22789024]

Martin KA, Anderson RR, Chang RJ, et al. Evaluation and treatment of hirsutism in premenopausal women: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2018. doi: 10.1210/jc.2018-00241.[PubMed 29522147]

McConnell JD, Roehrborn CG, Bautista OM, et al, “The Long-Term Effect of Doxazosin, Finasteride, and Combination Therapy on the Clinical Progression of Benign Prostatic Hyperplasia. Medical Therapy of Prostatic Symptoms (MTOPS) Research Group,” N Engl J Med, 2003, 349(25):2387-98.[PubMed 14681504]

Pole M and Koren G, “Finasteride. Does It Affect Spermatogenesis and Pregnancy,” Can Fam Physician, 2001, 47:2469-70.[PubMed 11785276]

Propecia (finasteride) [prescribing information]. Whitehouse Station, NJ: Merck & Co; January 2014.

Proscar (finasteride) [prescribing information]. Whitehouse Station, NJ: Merck & Co; September 2013.

Thompson IM, Goodman PJ, Tangen CM, et al. The influence of finasteride on the development of prostate cancer. N Engl J Med. 2003;349(3):215-224.[PubMed 12824459]

Thompson IM Jr, Goodman PJ, Tangen CM, et al. Long-term survival of participants in the prostate cancer prevention trial. N Engl J Med. 2013;369(7):603-610.[PubMed 23944298]

US Department of Health and Human Services; Centers for Disease Control and Prevention; National Institute for Occupational Safety and Health. NIOSH list of antineoplastic and other hazardous drugs in healthcare settings 2016. Updated September 2016. Accessed October 5, 2016.

Welk B, McArthur E, Ordon M, Anderson KK, Hayward J, Dixon S. Association of suicidality and depression with 5α-reductase inhibitors. JAMA Intern Med. 2017;177(5):683-691.[PubMed 28319231]

Brand Names: International

Alofecid (KR); Alopec (BD); Alopros 5 (ID); Androfin (LV); Aprodil (EC); Atepros (PH); Bearfina (KR); Benstat (TH); Binfin (SG); Binfin 5 (ZW); Chibro-Proscar (FR); Damocare (HK); Damopecia (KR); Daric (PY); Fina-5 (PH); Finapecia (EG); Finapros (PH); Finarid (PH); Finas (BD, SG); Finascar (JO); Finaspro (TW); Finaspros (CO); Finast (LK, VN); Finasta (AU); Finastar (KR); Finastid (HR); Finated (KR); Finatra (CN); Fincar (EG, HK, IN, KR, LK, MY); Finide (PH); Finiscar (QA); Finnacar (AU); Finpro (ID, ZA); Finstal-5 (PH); Finster (LV); Fintrid (IE); Firide (TH); Fistrin (CO); For-BPH (PH); Fynasid (TW); GPO-Finax (TH); Harifin (TH); Jun Neng (CN); Maxteride (HK); Monastar (KR); Nopecia (EG); Penester (LV, UA); Pro-Cure (IL); Profal (IE); Prohair (QA); Pronax (PH); Pronor (LK); Propecia (AE, AR, AT, AU, BR, BS, BZ, CN, CO, CR, CY, DO, EC, ES, GT, HK, HN, HR, IL, IS, JM, JP, KW, LB, LU, MT, MY, NI, NL, NZ, PA, PE, PH, RO, SA, SE, SG, SV, TH, TT, TW); Propeshia (MX); Proscar (AE, AR, AT, AU, BB, BD, BE, BG, BH, BM, BO, BR, CH, CL, CN, CR, CY, CZ, DE, DK, DO, EC, EE, EG, ES, FI, GB, GR, GT, GY, HK, HN, HR, HU, ID, IE, IT, JO, KR, KW, LB, LU, MT, MX, MY, NI, NO, NZ, PA, PE, PH, PK, PL, PR, PT, RO, RU, SA, SE, SG, SK, SR, SV, TH, TR, TW, VE, VN); Proseride (TH); Prosfin (BD); Prostacare (LB, QA); Prostan (UA); Prostanus (PH); Prostarinol (LV); Prosterid (HU); Prosteride (HK, PH, TH); Prostide (ID); Prostop (UY); Proteside (JO); Reprostom (ID); Skarex (KR); Stercia (SG); Stercia-5 (TH); Sterzar (TH); Tensen (TW); Uromedin (PY)

Finasteride (Patient Education – Adult Medication)
You must carefully read the “Consumer Information Use and Disclaimer” below in order to understand and correctly use this information

(fi NAS teer ide)

Brand Names: US

Propecia; Proscar

Brand Names: Canada

Propecia; Proscar

What is this drug used for?
  • It is used to help hair growth in male pattern baldness. It may take 3 months to see the full effect.
  • It is used to treat the signs of an enlarged prostate. It may take a few months to see the full effect.
  • It may be given to you for other reasons. Talk with the doctor.
What do I need to tell my doctor BEFORE I take this drug?
  • If you have an allergy to finasteride or any other part of this drug.
  • If you are allergic to any drugs like this one, any other drugs, foods, or other substances. Tell your doctor about the allergy and what signs you had, like rash; hives; itching; shortness of breath; wheezing; cough; swelling of face, lips, tongue, or throat; or any other signs.
  • If you are a woman. This drug is not approved for use in women. If you are a woman using this drug, talk with your doctor if you are pregnant, plan on getting pregnant, or are breast-feeding.
  • This drug may interact with other drugs or health problems.
  • Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take this drug with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.
What are some things I need to know or do while I take this drug?
  • For all uses of this drug:
  • Tell all of your health care providers that you take this drug. This includes your doctors, nurses, pharmacists, and dentists.
  • Avoid driving and doing other tasks or actions that call for you to be alert until you see how this drug affects you.
  • To lower the chance of feeling dizzy or passing out, rise slowly if you have been sitting or lying down. Be careful going up and down stairs.
  • This drug may affect certain lab tests. Tell all of your health care providers and lab workers that you take this drug.
  • Do not donate blood while using this drug and for 1 month after stopping.
  • Some doses of this drug may raise the chance of a type of prostate cancer. Talk with your doctor.
  • Rarely, male breast cancer has happened with this drug. Talk with your doctor.
  • This drug may lower sperm counts in men. This may affect being able to father a child. Talk with the doctor.
  • This drug is not approved for use in children. Talk with the doctor.
  • Pregnant women must not handle crushed or broken tablets. Talk with the doctor.
  • For enlarged prostate:
  • Have a rectal exam (to check prostate gland) and blood work (PSA test). Talk with your doctor.
What are some side effects that I need to call my doctor about right away?
  • WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:
  • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
  • A lump in the breast, breast soreness, or nipple discharge.
  • Enlarged breasts.
  • Very bad dizziness or passing out.
  • Low mood (depression).
  • For males, testicle pain.
What are some other side effects of this drug?
  • All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:
  • Dizziness.
  • Feeling tired or weak.
  • This drug may cause a change in sex ability in men or lowered interest in sex. This could go on after you stop this drug. Talk with your doctor if these effects go on or bother you.
  • These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.
  • You may report side effects to your national health agency.
How is this drug best taken?
  • Use this drug as ordered by your doctor. Read all information given to you. Follow all instructions closely.
  • Take with or without food.
  • Take this drug at the same time of day.
  • To gain the most benefit, do not miss doses.
  • Keep taking this drug as you have been told by your doctor or other health care provider, even if you feel well.
  • Read the package insert for more details.
What do I do if I miss a dose?
  • Skip the missed dose and go back to your normal time.
  • Do not take 2 doses at the same time or extra doses.
How do I store and/or throw out this drug?
  • Store in the original container at room temperature.
  • Protect from light.
  • Store in a dry place. Do not store in a bathroom.
  • Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
  • Throw away unused or expired drugs. Do not flush down a toilet or pour down a drain unless you are told to do so. Check with your pharmacist if you have questions about the best way to throw out drugs. There may be drug take-back programs in your area.
General drug facts
  • If your symptoms or health problems do not get better or if they become worse, call your doctor.
  • Do not share your drugs with others and do not take anyone else’s drugs.
  • Keep a list of all your drugs (prescription, natural products, vitamins, OTC) with you. Give this list to your doctor.
  • Talk with the doctor before starting any new drug, including prescription or OTC, natural products, or vitamins.
  • Some drugs may have another patient information leaflet. If you have any questions about this drug, please talk with your doctor, nurse, pharmacist, or other health care provider.
  • If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.