Emerging evidence & commentary on risks of finasteride as a treatment for hair loss
Merck told a simplified story of finasteride’s mechanism. In fact, the drug’s action predicts widespread disruptions of complex pathways which are critical for behavior and reproduction. Merck’s own research had shown this. Real world experience with finasteride confirms the connection: impairments in finasteride users affect systems regulated by these same pathways.
Alan, a 28-year-old man who experiencing hair loss, is participating in the Propecia clinical trial. Alan brings high hopes that the new drug will stop hair loss. An investigator examines Alan’s scalp and hair, recording figures on a form. She asks Alan if he experienced any side effects. None, he replies. He is then given a form to fill out…
In ancient Greece, Hippocrates and Aristotle observed that eunuchs did not go bald. Jumping ahead to the early 1940s, American anatomist James B. Hamilton reviewed histories of men with testosterone deficiency and found a pattern: the earlier the age of hormone deficiency, the less balding occurred.
Despite serious methodological shortcomings—including the preposterous use of on-drug safety data as a proxy for a post-drug condition—the authors nevertheless blame the post-drug syndrome on patient shortcomings. Zhang et al. have yoked bad logic to biased data in order to deflect attention away from drug harms.
Although finasteride came on the market in the 1990s, the underlying research began two decades earlier. The rationale for the drug emerged from a study of a unique group of people in a remote village in the Dominican Republic called Las Salinas. Locals there have long known about children who follow an unusual developmental path: … Read more
HIGHLIGHTS Merck received FDA approval for Propecia (finasteride 1 mg/day) in December 1997. Sales in the first year of marketing were reported to be $76 million. The peak years were 2010–2011, when Merck reported $447 million in Propecia sales in each year. In total, Merck booked an estimated $5.2 billion in sales of Propecia. We … Read more
Six months after discontinuing a Phase 3 finasteride trial, a man’s sexual adverse experience was unresolved. There were also 16 men whose drug-related sexual adverse experiences were unresolved at the conclusion of the trial.
Filings from lawsuits alleging persistent adverse effects of Propecia and Proscar in various jurisdictions in the United States and Canada, dating from 2011 to 2021.
These documents from 2006–2009 concern Merck’s response to postmarketing reports of persistent erectile dysfunction, male infertility and depressive disorders, among other adverse events, associated with use of finasteride. In 2006, the Swedish Medical Products Agency asked Merck for an analysis of all adverse events affecting the male reproductive system which persisted after stopping Propecia. In … Read more
Merck first developed finasteride for benign prostatic hyperplasia, a condition typically found in men aged 55 and older. After receiving approval for the application in 1992 and bringing the drug to market as Proscar, Merck decided to seek approval of finasteride for male pattern hair loss—to be branded as Propecia. In a 1994 memo below, … Read more