My Comments - This is a well thought out study and does demonstrate penile changes in rats that were given finasteride over a very short time frame. What this has to do with Peyronies Disease is not evident. The allegation that finasateride shrinks the penis is not all that convincing from this study. Technically, this is true as the Corpus Cavernosum is part of the penis, but how it affects the overall size of the penis, particularly the erect size, is not clear. Further, when these rats were given finasteride and then testosterone, the shrinkage was much less. Is there some mechanism by which a decreased Corpus Cavernosum possibly increases pressure on the Tunica resulting in scarring AKA Peyronies? An unanswered question.
My reader feedback indicates that a fair number of people in the medical profession read this site. Looking at the tissue samples of the Tunica Albuginea, i.e., control vs given finasteride, they look similar. Any medical professionals out there who read this site, please tell me what you think of the 2 tissue samples.
Does this study demonstrate that finasteride and Peyronies Disease are linked? No abnormalities noted in the Tunica Albuginea. I would give it a Grade D.
EFFECT OF ANDROGEN DEPRIVATION ON PENILE ULTRASTRUCTURE - Asian Journal of Andrology March 2003
Once again, an important study on this issue, not from the United States, but from China. This is an extremely small study and not on humans, but laboratory rats. However, if these results could be replicated on a larger human male group, this would be pretty close to a smoking gun linking finasteride to Peyronies Disease. Of course, this would require a leap of logic finding that the results in 18 rats are also applicable to a large scale group of human males.
Eighteen 9 week old male rats were divided in 3 equal groups. Group 1 - control Group 2 - castrated Group 3 - were given finasteride for a 4 week period and then sacrificed
The thickness of the Tunica Albuginea was significantly reduced in Group 2, but there was no significant difference between Group 1 and Group 3
Group 1 had the elastic fibers in the Tunica Albuginea very thick and regularly arranged. Group 3 did not have regularly arranged fibers and they were replaced by thick and irregularly arranged collagenous fibers. AKA Peyronies Disease
The Corpus Cavernosum in Group 1, the muscle fibers were rich and contained few elastic and collangenous fibers. In contrast, in Group 3 there was a considerable amount of irregularly and thick irregularly arranged collangenous fibers
This is a really small study and I was surprised that there were no photos of the tissue samples in the report. However, here are some photos from my files that illustrate the difference between healthy penis tissue and Peyronies:
Elastin in normal tissue with loose network of fibers extending in all directions; this permits stretch and contraction of penile tissue in nearly any direction.
Elastin in Peyroine's Disease: Note that the fibers are reduced in number and the fibers that are present are very short and abnormal. This tissue would not stretch normally.
Although there are many limitations, the grade I would give this study as proof there is a link between taking finasteride and developing Peyronies Disease is Grade B+.
There is an excellent website by the name of ehealthme. They use various methods to collect data on drugs and their effects. I have reprinted a very limited amount of their data concerning finasteride and Peyronies Disease.
This is a review of Peyronie's disease by studying 4,979 people who take Finasteride. We analyze: the time on Finasteride when people have Peyronie's disease, age of these people, the severity of Peyronie's disease, how they recovered, and common conditions and drugs used besides Finasteride. The review is created by eHealthMe based on reports from FDA and social media, and is updated regularly.
For patients like me, how are my drugs? On eHealthMe, you can research 300 million drug outcomes from FDA and social media since 1977. The results are personalized to your gender and age. Start now
Finasteride (latest outcomes) has active ingredients of finasteride. It is often used in enlarged prostate, hair loss. Commonly reported side effects of Finasteride include fatigue, dizziness, fatigue aggravated, weakness, dyspnoea exacerbated.
Peyronie's disease (bent penis) has been reported by people with erection problems, high blood pressure, depression, high blood cholesterol, hypothyroidism.
As of Dec, 23, 2013: 4,970 people reported to have side effects when taking Finasteride. Among them, 6 people (0.12%) have Peyronie's Disease.
Finasteride may or may not be related to the development of Peyronies Disease. Based on the evidence I have reviewed there is simply not enough evidence to establish even a weak cause and effect relationship between the two.