Proscar Side Effects

Generic Name: finasteride

Note: This document contains side effect information about finasteride. Some of the dosage forms listed on this page may not apply to the brand name Proscar.

Some side effects of Proscar may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

For the Consumer

Applies to finasteride: oral tablet

Along with its needed effects, finasteride (the active ingredient contained in Proscar) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking finasteride:

More common
  • Chills
  • cold sweats
  • confusion
  • dizziness, faintness, or lightheadedness when getting up from a lying or sitting position
Less common
  • Bloating or swelling of the face, arms, hands, lower legs, or feet
  • breast enlargement and tenderness
  • hives or welts
  • itchy skin
  • rapid weight gain
  • redness of the skin
  • skin rash
  • swelling of the lips and face
  • tingling of the hands or feet
  • unusual weight gain or loss
Incidence not known
  • Clear or bloody discharge from the nipple
  • dimpling of the breast skin
  • inverted nipple
  • lump in the breast or under the arm
  • persistent crusting or scaling of the nipple
  • redness or swelling of the breast
  • sore on the skin of the breast that does not heal

Some side effects of finasteride may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common
  • Decreased interest in sexual intercourse
  • inability to have or keep an erection
  • loss in sexual ability, desire, drive, or performance
Less common
  • Runny nose
  • sleepiness or unusual drowsiness
  • sneezing
  • stuffy nose
Less common or rare
  • Abdominal or stomach pain
  • back pain
  • decreased amount of semen
  • diarrhea
  • dizziness
  • headache
Incidence not known
  • Testicular pain

For Healthcare Professionals

Applies to finasteride: oral tablet

Genitourinary

Two hundred fourteen reports of gynecomastia in men taking finasteride (the active ingredient contained in Proscar) in the United States were received by the FDA between June 1992 and February 1995. Among those reported, fifty eight percent were taking additional medications that have been associated with gynecomastia. Sixty nine of 86 patients who discontinued finasteride treatment had partial or complete remission.

New reports of drug-related sexual adverse experiences have been reported to decrease with duration of therapy.

Genitourinary side effects have included impotence (1.1% to 18.5%), abnormal ejaculation (7.2%), decreased ejaculatory volume (0.9% to 2.8%), abnormal sexual function (2.5%), gynecomastia (2.2%), erectile dysfunction (1.3%), ejaculation disorder (1.2%), and testicular pain. The manufacturer has reported that in controlled clinical trials, 1.2% of patients on finasteride tablets discontinued therapy because of a drug-related sexual adverse experience. Postmarketing reports have included sexual dysfunction that continued after discontinuation of treatment, including erectile dysfunction, libido disorders, ejaculation disorders, and orgasm disorders; male infertility and/or poor seminal quality (normalization or improvement of seminal quality has been reported after discontinuation of finasteride); and testicular pain.

Endocrine

Endocrine side effects have included reductions in prostate specific antigen (PSA) levels of approximately 50%.

Finasteride may cause a decrease in PSA levels in patients with benign prostatic hyperplasia as well as in patients with prostate cancer. In one study, mean PSA reductions of 50% were noted, regardless of baseline levels. There was no indication that PSA levels were further suppressed in patients with prostate cancer.

PSA levels are commonly used in the screening process for prostate cancer. Patients who develop sustained increases in PSA while on finasteride therapy should be carefully evaluated for medical causes as well as noncompliance.

Nervous system

Nervous system side effects including decreased libido (1.6% to 10.0%), dizziness (7.4%), and somnolence (1.7%) have been reported.

Cardiovascular

Cardiovascular side effects including postural hypotension (9.1%) and hypotension (1.2%) have been reported.

General

General side effects including asthenia (5.3%), dizziness, headache, and abdominal pain have been reported.

Oncologic

Oncologic side effects have included a prevention or delay in the appearance of prostate cancer. However, finasteride (the active ingredient contained in Proscar) has also been linked to an increased risk of high grade prostate cancer. Postmarketing experience has included rare cases of male breast cancer.

Gastrointestinal

Gastrointestinal side effects including nausea and flatulence have been reported.

Dermatologic

A 58 year old man presented with an itchy, lumpy rash on upper and lower extremities following two weeks of finasteride (the active ingredient contained in Proscar) treatment for prostatism. The patient had no known allergies and was taking no other medications prior to the episode. The finasteride was discontinued and dapsone was initiated. The rash resolved two weeks after finasteride therapy was stopped.

Dermatologic side effects including rash have been rare. At least one case of cutaneous leukocytoclastic vasculitis has been associated with finasteride therapy. A case of solitary fixed drug eruption has also been reported.

Hypersensitivity

Postmarketing hypersensitivity side effects including rash, pruritus, urticaria, and angioedema (including swelling of the lips, tongue, throat, and face) have been reported.

Metabolic

Metabolic side effects including peripheral edema (1.3%) have been reported.

Respiratory

Respiratory side effects including rhinitis (1.0%) and dyspnea (0.7%) have been reported.

Psychiatric

Psychiatric side effects have included depression.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. Drugs.com does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.

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