Finasteride (birth defects)

[jake80]

I've been reading up about side effects of finisteride and I found this. I think a lot of people on this forum are young and would like to have children some day so this is quite concerning.

Here is the link

http://health.yahoo.com/other-other/finasteride ... 40863.html


This medication should not be used by men who may father a child, because it may cause birth defects in male babies. Women who are pregnant or might become pregnant should not handle crushed finasteride tablets. There is a small chance that the medication could get into the woman's system and cause a birth defect.

 

[DocBenway]

Re: Finasteride side effects

I have to see any true evidence of birth defects while on propecia. If it were true, then please someone shine some light on it.
This has been discussed many times here, but it seems like 95% of the people that take the pill on this forum greatly disagree with this claim.
As for prostate cancer, um, yeah I don't know.

 

[Ridgerunner7]

Re: Finasteride side effects

Wow! This really surprises me that no one is responding to this! Are these facts or just speculation? If it's fact that would make my decision to start finasteride very easy as I haven't even had my first child yet.

 

[treadstone]

Re: Finasteride side effects

This is from the FAQ on the main page of this site:

Q: Is there a problem if my wife gets pregnant while I'm taking Finasteride?

A: No. Originally Merck decided to err on the side of caution and warned against the possible problem of finasteride transfer in semen. This warning has since been removed. At issue is the theoretical danger that there could be genital birth defects in the male fetus. However, women who are or could get pregnant should avoid finasteride ingestion and the handling of broken finasteride tablets.

 

[bubka]

Also not that the dosage that caused the birth defect in male fetus of monkeys was a lot higher than touching a crushed pill.

 

[Pedro88]

FINASTERIDE AND BIRTH DEFECTS

There are very few more anxiety provoking times in anyone’s life than possibly causing a birth defect in one’s own unborn child. So, it’s quite understandable that the mention of a possible birth defect with the use of finasteride (Propecia 1mg and Proscar 5mg, Merck) would cause considerable anxiety and concern. The package insert for Proscar states under the section on Contraindications: “Because of the ability of Type II 5alpha reductase inhibitors to inhibit the conversion of testosterone to DHT, finasteride may cause abnormalities of the external genitalia of a male fetus of a pregnant woman who receives finasterideâ€. So, is the risk real? Theoretically, yes. Practically, no.

The specific birth defect that can be caused by the absence or inhibition of the Type II 5-alpha reductase enzyme in the male embryo is hypospadias. Hypospadias is a birth defect in which the urinary tract opening is on the ventral surface (under side) of the penis rather than at the tip of the penis. There have never been congenital abnormalities observed in female fetuses at any dosage of finasteride.

During the research and development phase of finasteride, studies were done on experimental animals. Rats, rabbits, and rhesus monkeys were given finasteride to determine its relationship to birth defects, i.e. hypospadias.

Hypospadias did occur in the male offspring, when pregnant rats were administered finasteride equivalent to 5-5000 times the amount of recommended for men in treating male pattern baldness (1mg/daily). The critical period during which these effects can be induced in male rats was determined to be during the 16th –17th days of gestation.

In rabbit fetuses exposed to finasteride in utero from days 6-18 of gestation at doses equivalent to 5000 times the recommended human dosage, no evidence of malformations was observed. This result would be expected, since there was no exposure during the critical period of genital system development in rabbits.

When pregnant rhesus monkeys were given intravenous finasteride at a level equivalent to at least 750 times the highest estimated exposure of pregnant women to finasteride from semen of men taking 1mg/day, there were no genital abnormalities observed.

In the human embryo, the sensitive period of external genitalia development is during the 7th - 9th weeks of gestation. Although the chromosomal and genetic sex of an embryo is determined at fertilization by the kind of sperm, either Y-bearing or X-bearing, that fertilizes the ovum, male and female morphological characteristics do not begin to develop until the seventh week. Prior to this time, the genital systems of the two sexes are similar, and the initial period of genital development is referred to as the ‘indifferent state of sexual development’. About six weeks after conception, if a Y chromosome is present in the embryo's cells (as it is in normal males), a gene on the chromosome directs the undifferentiated gonads to become testes. If the Y chromosome is not present (as in normal females), the undifferentiated gonads will become ovaries. If the gonads become testes, they begin to produce androgens, primarily testosterone, by about eight weeks after conception. These androgens stimulate development of the one set of the genital ducts into the epididymes, vas deferens, and ejaculatory duct. The presence of androgens also stimulates development of the penis and the scrotum. Hypospadias can result if there is inadequate production of androgens by the fetal testes.

Since the sensitive period of development of the external genitalia in the human embryo is the 7th to 9th weeks of gestation, there can be no danger to the child if the father is taking finasteride at the time of conception. Originally, Merck decided to err on the side of caution and warned against the possible problem of finasteride transfer in semen. This warning has since been removed from the package insert. Considering the medical/legal implications of a theoretically possible link of finasteride treatment to birth defects, it is reasonable to assume that Merck & Co. must be very confident in knowing that impregnating a woman while taking finasteride absolutely does not cause birth defects.

Nor is there any evidence of birth defects when the father taking finasteride has intercourse with the pregnant mother during the critical periods of sexual development. The in utero effects of finasteride exposure during the period of embryonic and fetal development (gestation days 20-100) were evaluated in the rhesus monkey, a species fairly predictive of human development. Intravenous administration of finasteride to pregnant monkeys at doses as high as 800ng/day (at least 60 to 120 times the highest estimated exposure of pregnant women to finasteride from semen of men taking 5mg/day) caused no abnormalities in male fetuses.

Still, Merck retains this admonition: “Women should not handle crushed or broken Propecia tablets when they are pregnant or may be potentially pregnant because of the possibility of absorption of finasteride and the subsequent potential risk to a male fetus. Propecia tablets are coated and will prevent contact with the active ingredient during normal handling, provided that the tablets have not been broken or crushed.â€

Considering that intravenous administration of finasteride to pregnant experimental animals during the critical periods of sexual development didn’t cause birth defects, there is no reason to believe that transdermal absorption of finasteride from handling broken tablets could cause birth defects in the male child. But, since Propecia has not been approved by the FDA for use by women, Merck has nothing to lose by retaining this warning. In fact, it has good p.r. value.

So, can finasteride cause birth defects? Yes, there is a theoretical possibility that it can, but the probability is close to nil, when finasteride is taken in the recommended dosages. Since Propecia was approved by the FDA on 22 December 1997 and Proscar on 28 August 1996, millions of doses of finasteride have been taken and there has not been a single case report of a birth defect. Now that’s reassuring information.

Richard Lee, M.D.


Andersson, S.; Berman, D. M.; Jenkins, E. P.; Russell, D. W.: Deletion of steroid 5-alpha-reductase 2 gene in male pseudohermaphroditism. Nature 354: 159-161, 1991
Greene, S. A.; Symes, E.; Brook, C. G. D.: 5-Alpha-reductase deficiency causing male pseudohermaphroditism. Arch. Dis. Child. 53: 751-753, 1978
Imperato-McGinley, J.; Gautier, T.: Inherited 5-alpha-reductase deficiency in man. Trends Genet. 2: 130-133, 1986
Moore, KL and Persaud, TVN: Before We Are Born-Essentials of Embryology and Birth Defects; 6th Edition, Saunders 2003
New England J of Med: 1994, Jan 13; 330 (2) 120-5
Physicians Desk Reference, 58th Edition, 2004, pp. 2172-2178
Thigpen, A. E.; Davis, D. L.; Milatovich, A.; Mendonca, B. B.; Imperato-McGinley, J.; Griffin, J. E.; Francke, U.; Wilson, J. D.; Russell, D. W.: The molecular genetics of steroid 5-alpha-reductase 2 deficiency. J. Clin. Invest. 90: 799-809, 1992
http://encarta.msn.com/encyclopedia_761 ... tml#endads
http://science.howstuffworks.com/human- ... ction5.htm
Sex-organ development is determined by the third month of development.
http://www.people.virginia.edu/~rjh9u/sexdev.html
http://www.lindasy.com/cgi-local/SoftCa ... ?E+scstore

 

[EasyEd]

It's the exact reason I've stopped finasteride at the moment. My wife and I "pulled the goalie" so to speak and will hopefully be having kids soon. Once they're born, I'll get back on, but for now, I'm off.

 

[bubka]

Nice post Pedro88, that should put things to eas when 1,000x and 750x times the normal dosages did not cause birth defects.

 

[Nathaniel]

And... if you are still not convinced with the Bubka's high dosage side of the argument here is another so you can sleep better:

Since Propecia was approved by the FDA on 22 December 1997 and Proscar on 28 August 1996, millions of doses of finasteride have been taken and there has not been a single case report of a birth defect . Now that’s reassuring information.

btw thanx Pedro.

 

[Harie]

My 2nd son was conceived when I was on finasteride, and the 3rd one when I was on dutasteride (2x/week). The son conceived while on finasteride is the cutest kid ever and everyone comments on it, plus he's friggin' smart for only being 2 years old. We've been approached by modeling agencies that want to use him in child ads.

The kid conceived while on dutasteride has a huge penis, but isn't as cute as the 2 year old, though he's a good looking baby too. He's 100% normal for development at his age.

So in my experience - if you want a very cute kid, take finasteride. If you want a kid that, later in life, could potentially be a p**rn star - use dutasteride.

 

[BlahBlah12]

this also is my biggest fear. I honestly do not want my son to have ambiguous genitalia, or a small penis.

This sounds ridiculous, but does anyone fear that their child might be born with a rather small penis because they took propecia while trying to have a child?

 

[bubka]

No, but I fear that I might be stuck by a meteorite.