Sperm DNA Damage from Finasteride?
Snippet from the case report:
The significant reduction in DFI within 3 months of finasteride cessation and continued improvement suggests a causal link between finasteride and sperm DNA damage. We hypothesize that low-dose finasteride may exert a negative influence on sperm DNA integrity, resulting in increased pregnancy losses. We suggest that in infertile men using finasteride, sperm DFI should be measured in addition to semen parameters, and a trial of discontinuation of finasteride may be warranted.
Read the rest — Finasteride-induced secondary infertility associated with sperm DNA damage
This is a single case report published earlier this year in Fertility and Sterility about a 48 year old man that shows a casual link between finasteride and sperm integrity. It summarizes that some negative impact of finasteride on sperm’s DNA fragmentation index (DFI) which was reversible with stopping the medication.
I’m asked all the time about finasteride and fertility, and all I can go off of is what is in the literature and from what my patients have told me. I’ve had many male patients with no problems getting their wife/girlfriend pregnant, but perhaps for men who are taking finasteride that wish to conceive children, they should talk to their prescribing physician about discontinuing the medication during the period of the female’s cycle between 11-21 days from the onset of menses. There is no assurance that such a step will address the problem identified in this article or that you will have such an issue to begin with.
Does this study have any implications of finasteride’s effect on child/fetus developent?
Well, this is not a good news. If it increases only the pregancy losses, well it is “restricted”, but what about the child or fetus ? I hope that there will be studies about this.
Mark – I’m also interested in this. Does the effect on the sperm mean there will be any implication on the child/fetus? This is really important for anyone considering taking the drug.
Merck’s phase 2 clinical trials demonstrated that finasteride use significantly reduced sperm count in the treatment group. They did not test for this in the phase 3 (final) trials since the phase 3 trials are what is publicized and presented to doctors. I do not know anything about changes in DFI other than what Dr. Rassman posted above. However, if you look at the Proscar (5mg) warning label, it says that sperm volume and consistency can become watery due to the drug and will take a median of 84 weeks (> 1.5 years) to return to baseline. The use of the median figure is deceptive as it is outlier resistance and can conceal subjects who took many years to recover or never recovered.
To answer the second question – yes there is a chance of finasteride affecting the development of a fetus. While this fact is not widely known, the drug was modeled off the low DHT levels of pseudohermaphrodites in the Caribbean. A lack of 5-alpha reductase in the earliest stages of life is well-known to cause development of ambiguous genitalia. More specifically, with respect to finasteride use and birth defects, there have been about 100 cases reported to the FDA of children with birth defects. These are mainly hypospadias, which are extremely rare in the general population, but prevalent in the population of Dominican pseudohermaphrodites. Finasteride was contraindicated for women for fear that this problem would be widespread. The likelihood that you would create a defective child while on the medication appears to be slim, but the existing data is pretty sparse, although it can clearly happen as demonstrated from the FDA reports.
The effect in women is understandable. What seems less clear is whether or not fetus DNA abnormalities can be caused by a male finasteride user impregnating a female.
I apologize if I did not make myself clear. The FDA reports were for cases in which men and not women were using the drug. Many of the doctors who had written the reports concluded that the finasteride had transferred to the woman through bodily contact. Other methods of contamination were concretely ruled out in these write ups.
What Mark is asking, Jeremy, is if sperm having DNA damage, or other factors that has effected the QUALITY of the sperm from the use of finasteride, will have an effect on the baby IF it is concieved.
NOT the result of the finasteride itself coming into contact with the fetus, but the result if the damaged sperm itself creating the baby. Yes, a miscarriage is more likely, but if conceived is there a risk on the child’s health.
Some articles reporting that sperm DNA damaged sperm can be passing genetic defects on to the unborn child.
Something to think about.