Sorry, but I'm don't think I agree with some of the responses.
The "Intended Use" is the overall purpose of the device and does not include the users or the patient population. Take a knife or a scalpel as an example, the intended use may be to cut tissue; or a ECG sensor - acquiring heart electrical activity; or a glucose tests. The last one is a good example of a device with one intended use but multiple indications that results in Rx or OTC designations. The regulation classification is 21 CFR 862.1345 Glucose test system; and have a number of product codes defining specific use e.g. NBW, MRV, LFR, CGA, and a few others.
The indications for use, on the other hand, specify who is the user, what is the patient population, and any specific diseases, conditions or the anatomical site the device is supposed to treat or diagnose.
For the 510(k) substantial equivalence, the "intended use" must be the same, not the "indications for use". Otherwise you could not use 510(k) if you wanted to expand the patient population, or add another condition or treatment site, etc.
So to answer sunshineshu's question, using an OTC predicate device may be a viable predicate. It's typically much more difficult to obtain OTC designation when using an Rx predicate, than narrowing new device's indications to Rx only.