Summary Safety Review - Propecia (finasteride 1 mg) and Proscar (finasteride 5 mg) - Assessing the Potential Risk of Seizures

August 05, 2016

Product

Propecia (finasteride 1 mg), Proscar (finasteride 5 mg), and generics

Potential Safety Issue

Seizures

Key Messages

• Propecia (finasteride 1 mg) and generics are used to treat hair loss in men (androgenetic alopecia). Proscar (finasteride 5 mg) and generics are used to treat prostate gland enlargement (benign prostatic hyperplasia).
• A safety review was carried out by Health Canada after cases of seizures with finasteride use were published in the WHO Pharmaceuticals Newsletter^{Footnote a}.
• The Health Canada safety review findings did not support a link between seizures and finasteride. Health Canada will continue to monitor the safety of finasteride products.

Overview

Health Canada carried out a safety review to look at the potential risk of seizures in patients taking finasteride after cases of seizures were published in the WHO Pharmaceuticals Newsletter^{Footnote a}.

Use in Canada

• Propecia (finasteride 1 mg) is used to treat hair loss in men (androgenetic alopecia). Proscar (finasteride 5 mg) is used to treat prostate gland enlargement (benign prostatic hyperplasia). There are generic finasteride products (1 mg and 5 mg) available in Canada that are also used to treat these respective conditions.
• While finasteride is not indicated for use in women, Health Canada is aware that it has been used in women for the treatment of conditions such as hair loss.
• Proscar has been sold in Canada since 1992 and Propecia since 1998. About 1.2 million prescriptions (new and refills) for finasteride-containing products were dispensed in Canada in 2014. Most were given for the treatment of prostate gland enlargement.

Safety Review Findings

• At the time of the review, 95 unique cases of seizures associated with finasteride use were found worldwide. Of these, 45 were relevant for this review and further assessed. Ten of the 45 cases were Canadian cases. No female cases were reported in Canada. Upon review of these cases, no conclusions could be made on whether finasteride played a role in seizures because the information contained in the reports was limited and some patients had other conditions that could cause seizures.
• The scientific literature showed that studies in animals with seizures indicated an increased risk of seizures with finasteride. However, it did not find enough evidence to support an increased risk of seizures in people treated with finasteride.

Conclusions and Actions

• Health Canada's safety review findings did not support a link between an increased risk of seizures in patients treated with finasteride.
• Health Canada has asked the manufacturers of Propecia and Proscar to continue to provide information on this safety issue.
• Health Canada will continue to monitor safety information involving finasteride products, as it does for all health products on the Canadian market, to identify and assess potential harms. Health Canada will take appropriate and timely action if and when any new health risks are identified.

Additional Information

The analysis that contributed to this safety review included scientific and medical literature, Canadian and international adverse reaction reports and what is known about the use of this drug both in Canada and internationally.

For additional information, contact the Marketed Health Products Directorate.