New Finasteride Lawsuit Brings Renewed Attention to Psychiatric, ED Adverse Event Reports

Alicia Ault

September 23, 2021

A new lawsuit seeking to force the Food and Drug Administration to act on a request to add stricter warnings to finasteride or remove it from the market may rekindle a debate on whether some of the observed side effects from the hair loss drug merit a closer look and, potentially, better counseling and monitoring from clinicians.

The nonprofit advocacy group Public Citizen filed the suit on behalf of the Post-Finasteride Syndrome Foundation (PFSF) in the U.S. District Court for the District of Columbia. The PFSF had filed a citizen's petition in 2017 that requested that the FDA either take the 1-mg formulation off the market, or add warnings about the potential for erectile dysfunction, depression, and suicidal ideation, among other adverse reactions.

The PFSF has alleged that long-term use of Propecia (and its generic equivalents) can lead to postfinasteride syndrome (PFS), characterized by sexual dysfunction and psycho-neurocognitive symptoms. The symptoms may continue long after men stop taking the drug, according to PFSF.

Public Citizen said the FDA needs to take action in part because U.S. prescriptions of the hair loss formulation "more than doubled from 2015 to 2020," and online and telemedicine companies such as Hims, Roman, and Keeps "aggressively market and sell generic finasteride for hair loss." According to GoodRx, a 1-month supply of generic 1-mg tablets costs as little as $8-$10.

Both Canadian and British regulatory authorities have added warnings about depression and suicide to the Propecia label but the FDA has not changed its labeling. An agency spokesperson told this news organization that the "FDA does not comment on the status of pending citizen petitions or on pending litigation."

Propecia's developer, Merck, has not responded to several requests for comment from this news organization.

Why some patients develop PFS and others do not is still not understood, but some clinicians said they counsel all patients on the risks of severe and persistent side effects that have been associated with Propecia.

Robert M. Bernstein, MD, of the department of dermatology at Columbia University, New York, and a fellow of the International Society of Hair Restoration Surgery, said that 2%-4% of his patients have some side effects, similar to the original reported incidence, with sexual dysfunction being the most common.

If a man experiences an adverse effect, the drug should be stopped, Bernstein said in an interview. He noted that "there seems to be a significant increased risk of persistent side effects in people with certain psychiatric conditions, and those people should be counseled carefully before considering the medication."

"Everybody should be warned that the risk of persistent side effects is real but in the average person it is quite uncommon," added Bernstein, founder of Bernstein Medical, a division of Schweiger Dermatology Group focusing on the diagnosis and treatment of hair loss. "I don't think it should be withdrawn from the market," he said.

Alan Jacobs, MD, a Manhattan-based neuroendocrinologist and behavioral neurologist in private practice who said he has treated hundreds of men for PFS, and who is an expert witness for the plaintiff in a suit alleging that finasteride led to a man's suicide, said that taking the drug off the market would be unfortunate because it helps so many men. "I don't think you need to get rid of the drug per se," he said in an interview. "But very rapidly, people need to do clinical research to find out how to predict who's more at risk," he added.

Michael S. Irwig, MD, associate professor of medicine at Harvard Medical School, Boston, who has studied the persistent sexual and nonsexual side effects of finasteride, said he believes there should be a boxed warning on the finasteride label to let the men who take it "know that they can have permanent persistent sexual dysfunction, and/or depression and suicide have been noted with this medicine.

"Those who prescribe it should be having a conversation with patients about the potential risks and benefits so that everybody knows about the potential before they get on the medicine," said Irwig, who also is an endocrinologist at Beth Israel Deaconess Medical Center in Boston.

Other Countries Warn of Psychiatric Effects

The FDA approved the 1-mg form of finasteride for male pattern hair loss in 1997.

In 2012, the label and the patient insert were updated to state that side effects included less desire for sex, erectile dysfunction, and a decrease in the amount of semen produced, but that those adverse events occurred in less than 2% of men and generally went away in most men who stopped taking the drug.

That label change unleashed a flood of more than 1,000 lawsuits against Merck. The company reportedly settled at least half of them for $4.3 million in 2018. The Superior Court of New Jersey closed out the consolidated class action against Merck in May 2021, noting that all of the cases had been settled or dismissed.

The suits generally accused Merck of not giving adequate warning about sexual side effects, according to an investigation by Reuters. That 2019 special report found that Merck had understated the number of men who experienced sexual side effects and the duration of those symptoms. The news organization also reported that from 2009 to 2018, the FDA received 5,000 reports of sexual or mental health side effects – and sometimes both – in men who took finasteride. Some 350 of the men reported suicidal thoughts, and there were 50 reports of suicide.

Public Citizen's lawsuit alleges that VigiBase, which is managed by the World Health Organization Collaborating Centre for International Drug Monitoring, lists 378 cases of suicidal ideation, 39 cases of suicide attempt, and 88 cases of completed suicide associated with finasteride use. VigiBase collects data from 153 countries on adverse reactions to medications.

In February 2021, more documents from the class action lawsuits were unsealed in response to a Reuters request. According to the news organization, the documents showed that Merck knew of reports of depression, including suicidal thoughts, as early as 2009.

However, according to Reuters, the FDA in 2011 granted Merck's request to only note depression as a potential side effect, without including the risk of suicidal ideation.

The current FDA label notes a small incidence of sexual dysfunction, including decreased libido (1.8% in trials) and erectile dysfunction (1.3%) and mentions depression as a side effect observed during the postmarketing period.

The Canadian label has the same statistics on sexual side effects but is much stronger on mental adverse effects: "Psychiatric disorders: mood alterations and depression, decreased libido that continued after discontinuation of treatment. Mood alterations including depressed mood and, less frequently, suicidal ideation have been reported in patients treated with finasteride 1 mg. Patients should be monitored for psychiatric symptoms, and if these occur, the patient should be advised to seek medical advice."

In the United Kingdom, patients prescribed the drug are given a leaflet, which notes that "Mood alterations such as depressed mood, depression and, less frequently, suicidal thoughts have been reported in patients treated with Propecia," and advises patients to stop taking the drug if they experience any of those symptoms and to discuss it with their physician.

Public Citizen noted in its lawsuit that French and German drug regulators have sent letters to clinicians advising them to inform patients of the risk of suicidal thoughts and anxiety.

Is There Biological Plausibility?

To bolster its argument that finasteride has dangerous psychiatric side effects, the advocacy organization cited a study first published in JAMA Dermatology in late 2020 that investigated suicidality and psychological adverse events in patients taking finasteride.

David-Dan Nguyen, MPH, and his colleagues at Brigham and Women's Hospital in Boston, McGill University, Montreal, and the University of Montreal, examined the VigiBase database and found 356 cases of suicidality and 2,926 psychological adverse events; cases were highest from 2015 to 2019.

They documented what they called a "significant disproportionality signal for suicidality (reporting odds ratio, 1.63; 95% confidence interval, 2.90-4.15) and psychological adverse events (ROR, 4.33; 95% CI, 4.17-4.49) with finasteride, especially in younger men and those with alopecia, but not in older men or those with benign prostatic hyperplasia.

The study authors noted that some studies have suggested that men with depression have low levels of the neurosteroid allopregnanolone, which is produced by the 5-alpha reductase enzyme. Finasteride is a 5-alpha reductase inhibitor.

According to Public Citizen's lawsuit, "The product labeling does not disclose important information about finasteride's mechanism of action," and "the drug inhibits multiple steroid hormone pathways that are responsible for the formation of brain neurosteroids that regulate many critical functions in the central nervous system, like sexual function, mood, sleep, cognitive function, the stress response, and motivation."

Jacobs said that "there's a lot of good solid high-quality research, mostly in animals, but also some on humans, showing a plausible link between blocking 5-alpha reductase in the brain, deficiency of neuroactive steroids, and depression."

The author of an accompanying editorial, Roger S. Ho, MD, MPH, an associate professor in the department of dermatology, New York University, was skeptical. "Without a plausible biological hypothesis pharmacodynamically linking the drug and the reported adverse event, this kind of analysis may lead to false findings," Ho said in the editorial about the Nguyen study.

Ho also wrote that he believed that the lack of a suicidality signal for dutasteride, a drug with a similar mechanism of action, but without as much media attention, "hints at a potential reporting bias unique to finasteride."

He recommended that clinicians "conduct a full evaluation and a detailed, personalized risk-benefit assessment for patients before each prescription of finasteride."

Important Medicine, Important Caveats

Jacobs said that many of the men who come to him with side effects after taking finasteride have "been blown off by most of the doctors they go to see."

Urologists dismiss them because their sexual dysfunction is not a gonad issue. They are told that it's in their head, said Jacobs, adding that, "it is in their head, but it's biological."

The drug's label advises that sexual side effects disappear when the drug is stopped. "That's only true most of the time, not all of the time," said Jacobs, adding that the persistence of any side effects impacts what he calls a "small subset" of men who take the drug.

"We have treated tens of thousands of patients who have benefited from the medicine and had no side effects," said Bernstein. "But there is a lot that's still not known about it."

Even so, "baldness in young people is not a benign condition," he said, adding that it can be socially debilitating. "An 18-year-old with a full head of thick hair who's totally bald in 3 or 4 years – that can totally change his psyche," Bernstein said. Finasteride may be the best option for those young men, and it is an important medication, he said. Does it need to be used more carefully? "Certainly you can't argue with that," he commented.

Bernstein and Irwig reported no conflicts. Jacobs disclosed that he is an expert witness for the plaintiffs in a suit against Propecia maker Merck.

This article originally appeared on, part of the Medscape Professional Network.


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