I did some digging on the official site and found more information.

http://www.tsa.gov/travelers/airtrav...al_1374.shtm#4

All medications in any form or type (for instance, pills, injectables, or homeopathic) and associated supplies (syringes, Sharps disposal container, pre-loaded syringes, jet injectors, pens, infusers, etc.) are allowed through the security checkpoint once they have been screened.
...
Medication and related supplies are normally X-rayed. However, as a customer service, TSA now allows you the option of requesting a visual inspection of your medication and associated supplies.

* You must request a visual inspection before the screening process begins; otherwise your medications and supplies will undergo X-ray inspection.
...
* Any medication and/or associated supplies that cannot be cleared visually must be submitted for X-ray screening. If you refuse, you will not be permitted to carry your medications and related supplies into the sterile area.

It's not entirely clear but it seems to mean that I can put a <3 oz medical liquid plus its syringes into my carry-on, and not say anything about it, if I am OK with it being X-rayed on the belt. If not, I need to declare it for visual inspection.