Marfans disease questions

I know Marfans is a connective tissue disorder but i have questions about my arota.  So my dilation is mild, at around low-mid 40s mm large.  I'm currently on 12.5 mg atenenol and 25 mg losartan/cozaar.  Is it okay to take these drugs in high dosage together?  Mainly because I've been doing some research on the web, and noticed how lost of people on this forum are reporting after taking a very high dosage of valsartan that there aorta shrunk quite a bit.  So I would like to know if a dosage of around 25 mg of atenenol, (I take atenenol because I'm a very active person), and a high one of losartan would be a bad combination of the two drugs.  Also what is the difference of losartan and valsartan?  

[nickppatel]

Both great questions.  Personally, I am not aware of any major risk in taking these drugs together.  I know some studies have reported adverse effects of taking ARBs (like losartan/valsartan) with ACE inhibitors, but even that is not firmly established for healthy adults.  So short answer is no, there really should not be any problem taking the beta blocker with the ARB.  I take both carvedilol and valsartan.

Second question: the difference between the drugs is subtle.  They both belong to the ARB family.  Losartan is the more "popular" drug for aortic therapy because that is the drug that some researchers have chosen to pursue for clinical studies.  However, my experience in interacting with various people who have Marfans is that any of these ARBs will work.  Currently telmisartan looks like it has the strongest ability to penetrate aortic tissue and thus might be the best bet.  Valsartan, candesartan, irbesartan, all are good too.  There is a theory that losartan, despite its current popularity, is NOT the best drug to use because it is a surmountable drug, meaning it could theoretically lose effectiveness over time.  Some of the other drugs I mentioned, like valsartan and telmisartan, are insurmountable drugs and theoretically would NOT lose their effectiveness over time.

If I was in your shoes, I would find a physician who reads all the latest studies and discuss taking atenolol + telmisartan combo.  The MOST IMPORTANT thing is to take an ARB dosage that is GREAT ENOUGH FOR YOUR BODY SIZE.  Otherwise, it will do nothing.  25 mg losartan is unlikely to have any effect on a regular size adult.  If you are an average size adult male, talk to your doctor about taking a dosage at the FDA approved maximum (for losartan, 100mg).  If you are bigger, then consider a higher dosage.  

After you begin a higher dosage, two things are important:  1) continue monitoring aortic size to see if the dosage is sufficient or not.  Usually we tend to see a reduction in aortic diameter within 6 months, sometimes 12 months.  2) check potassium levels through blood testing.  In some people, taking ARBs can push potassium levels too high, but it is very uncommon.

Best,
N