Singulair and Propecia

I have been on Propecia for 7 years, and it worked very well until approximately 6 months ago. I noticed my hair starting to thin after taking a drug called Singulair to help with exercised induced asthma. I have seen some blogs indicating that Singulair can cause hair loss.

I guess I have three questions:

1. Have you seen an cases where certain drugs (e.g. Singulair) can reduce the effectiveness or stop the effectiveness of Propecia?
2. Does Propecia just stop working after a certain amount of time?
3. Are there greater dosages of Propecia available? And, if so have they proven to be more effective?

Thanks for this blog. It is very good. I look forward to your response.

1. I have not seen a case where a drug like that can reduce the effectiveness of Propecia (particularly Singulair, since some of my patients do take that asthma/allergy medication)
2. Propecia does not just stop working. It is just that you are continuing to lose hair. Propecia just slows it down. It may be coincidental or you may be trying to establish a causal relationship between hair loss and another extrinsic factor.
3. Propecia is 1mg of finasteride, and is approved as a hair loss treatment. Finasteride is also available in 5mg strength, called Proscar (brand name), and is used to treat men with prostate problems. Men taking Proscar for their prostate can have a side effect of hair growth on their scalp. In fact, this is how Propecia was discovered. It is important to note that taking high dose of Propecia will not be effective for more hair growth. 1mg finasteride is all you need. If you increase the dose, you will only have an increased potential for undesirable side effects.