Drug labels

Drug labels include clinical trial results and ‘postmarketing’ information. Clinical trials are conducted before the drug is approved. Postmarketing experience lists adverse events reported after the drug was approved. Below are excerpts on adverse effects. For full details see the original documents.

US Food & Drug Administration labels:

Propecia (finasteride 1 mg)

Patient Information – April 2012

View original document (PDF). See also: A history of changes to the Propecia label

Excerpts with emphasis added:

The most common side effects of PROPECIA include:

decrease in sex drive
trouble getting or keeping an erection
a decrease in the amount of semen

The following have been reported in general use with PROPECIA [emphasis added]:

• breast tenderness and enlargement. Tell your healthcare provider about any changes in your breasts such as lumps, pain or nipple discharge.
decrease in sex drive that continued after stopping the medication;
• allergic reactions including rash, itching, hives and swelling of the lips and face;
problems with ejaculation that continued after stopping medication;
testicular pain;
difficulty in achieving an erection that continued after stopping the medication;
male infertility and/or poor quality of semen.
• in rare cases, male breast cancer.

Note: In June 2022, FDA required a new adverse reaction to be added to Prescribing Information (below): suicidal ideation and behavior. It does not appear in Patient Information. For background, see a Reuters story and this post.

Highlights of Prescribing Information – August 2022

View original document (PDF)

Excerpt from Section 6: Adverse Reactions (p. 3) with emphasis added:


6.1 Clinical Trials Experience


Clinical Studies for PROPECIA (finasteride 1 mg) in the Treatment of Male Pattern Hair Loss

In three controlled clinical trials for PROPECIA of 12-month duration, 1.4% of patients taking PROPECIA (n=945) were discontinued due to adverse experiences that were considered to be possibly, probably or definitely drug-related (1.6% for placebo; n=934).

Clinical adverse experiences that were reported as possibly, probably or definitely drug-related in ≥1% of patients treated with PROPECIA or placebo are presented in Table 1.

Integrated analysis of clinical adverse experiences showed that during treatment with PROPECIA, 36 (3.8%) of 945 men had reported one or more of these adverse experiences as compared to 20 (2.1%) of 934 men treated with placebo (p=0.04). Resolution occurred in men who discontinued therapy with PROPECIA due to these side effects and in most of those who continued therapy. The incidence of each of the above adverse experiences decreased to ≤0.3% by the fifth year of treatment with PROPECIA.

In a study of finasteride 1 mg daily in healthy men, a median decrease in ejaculate volume of 0.3 mL (-11%) compared with 0.2 mL (-8%) for placebo was observed after 48 weeks of treatment. Two other studies showed that finasteride at 5 times the dosage of PROPECIA (5 mg daily) produced significant median decreases of approximately 0.5 mL (-25%) compared to placebo in ejaculate volume, but this was reversible after discontinuation of treatment.

In the clinical studies with PROPECIA, the incidences for breast tenderness and enlargement, hypersensitivity reactions, and testicular pain in finasteride-treated patients were not different from those in patients treated with placebo.

[Omitted: trials of PROSCAR (finasteride 5 mg) and AVODART (dutasteride)]

6.2 Postmarketing Experience

The following adverse reactions have been identified during post approval use of PROPECIA…

Hypersensitivity Reaction: hypersensitivity reactions such as rash, pruritus, urticaria, and angioedema (including swelling of the lips, tongue, throat, and face);

Reproductive System: 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); testicular pain; hematospermia.

Neoplasms: male breast cancer;

Breast disorders: breast tenderness and enlargement;

Nervous System/Psychiatric: depression, suicidal ideation and behavior

Note: In June 2022, FDA required a new adverse reaction to be added to Prescribing Information: suicidal ideation and behavior. It does not appear in Patient Information. Background is in a Reuters story and this post.

Updates required by FDA – June 2022

View FDA letter (PDF)

Excerpt from p. 43 with emphasis added:

…[W]e are requiring that Organon make labeling changes under section 505(0)(4) of the FD&C Act to clarify the risks of use of Propecia. We are requiring the addition of suicidal ideation and behavior to the list of nervous system/psychiatric reactions in the ADVERSE REACTIONS (Postmarketing Experience) section… We are requiring that Organon change the Propecia labeling to add sexual adverse events mentioned in the ADVERSE REACTIONS (Clinical Trials Experience) section to PATIENT COUNSELING INFORMATION. We are requiring that the following reactions be added to the PATIENT COUNSELING INFORMATION section of the Propecia labeling: decreased libido, erectile dysfunction, and ejaculation disorder, including decreased ejaculate volume

See also: History of changes to the Propecia label

Avodart (dutasteride 0.5 mg)

Patient information

View original document (PDF)

Excerpt with emphasis added:

What are the possible side effects of AVODART? AVODART may cause serious side effects, including:

Rare and serious allergic reactions, including:

• Swelling of your face, tongue, or throat
• Serious skin reactions, such as skin peeling

Get medical help right away if you have these serious allergic reactions.

Higher chance of a more serious form of prostate cancer

The most common side effects of AVODART include:

trouble getting or keeping an erection (impotence)*
a decrease in sex drive (libido)*
ejaculation problems*

• enlarged or painful breasts. If you notice breast lumps or nipple discharge, you should talk to yourhealthcare provider.

*Some of these events may continue after you stop taking AVODART.

Depressed mood has been reported in patients receiving AVODART.

Highlights of Prescribing Information

View original document (PDF)

Excerpts with emphasis added:

5.6 Effect on Semen Characteristics

The effects of dutasteride 0.5 mg/day on semen characteristics were evaluated in healthy men throughout 52 weeks of treatment and 24 weeks of post-treatment follow-up. At 52 weeks, compared with placebo, dutasteride treatment resulted in mean reduction in total sperm count, semen volume, and sperm motility; the effects on total sperm count were not reversible after 24 weeks of follow-up. Sperm concentration and sperm morphology were unaffected and mean values for all semen parameters remained within the normal range at all timepoints. The clinical significance of the effect of dutasteride on semen characteristics for an individual patient’s fertility is not known [see Use in Specific Populations (8.3)].


6.1 Clinical Trials Experience


• The most common adverse reactions reported in subjects receiving AVODART were impotence, decreased libido, breast disorders (including breast enlargement and tenderness), and ejaculation disorders.

• Trial withdrawal due to adverse reactions occurred in 4% of subjects receiving AVODART and 3% of subjects receiving placebo in placebo-controlled trials with AVODART. The most common adverse reaction leading to trial withdrawal was impotence (1%).

a These sexual adverse reactions are associated with dutasteride treatment (including monotherapy and combination with tamsulosin). These adverse reactions may persist after treatment discontinuation. The role of dutasteride in this persistence is unknown.
b Includes breast tenderness and breast enlargement.

6.2 Postmarketing Experience

The following adverse reactions have been identified during post-approval use of AVODART. […] These reactions have been chosen for inclusion due to a combination of their seriousness, frequency of reporting, or potential causal connection to AVODART.

Immune System Disorders

Hypersensitivity reactions, including rash, pruritus, urticaria, localized edema, serious skin reactions, and angioedema.


Male breast cancer.

Psychiatric Disorders

Depressed mood.

Reproductive System and Breast Disorders

Testicular pain and testicular swelling.