I wish I could be more positive but being quite familiar with the healthcare/medical field, I'd say that there's "HUGE" difference between the two terms, Alternative Medicine & Alternative Medication, so much so that I hardly ever remember hearing the latter; may be its different with general public. Actually when you type "AlternativeMedicine" together in Google it gives only ONE result and says "Did you mean: Alternative Medicine", but when you type the latter together as "AlternativeMedicine" it gives you almost 12K results so even with Google the recognition diference is huge. However, if you try Alternative Treatment/Therapy you'd get much better results both with SEs and the genral public.
I'd say in this particular area (healthcare/medicine) if you find a an equally strong/popular word with .US (often even better with .INFO) then definitely go for it than .com. As new tlds gain recognition one is more likely see the first "converts" (from .com to .INFO or .US) in this area. Even before I got into domains I never felt okay with commercial-sounding .com used for medical/healthcare terms; in fact, .org carries much more professional prestige in this regard. Although .com's usage in medicine has become more acceptable in last 2-3 years I'd argue its been primarily due to lack of proper alternatives that have now arrived and need to gain their entry into people's radar screen. Good Luck.
