If a drug doesn't work, you don't add to it -- you only add to drugs that are working but just not well enough. Keep in mind that the older we get often the more difficult these meds are, and the recommended doses tend to go down. What I would do is make your decision quickly rather than wait a whole long time, as these meds are not easy to stop taking and get harder the longer you're on them. The general rule is 4-6 weeks for them to start working, though the side effects, unfortunately, start right away. What my psychiatrist did because Lexapro didn't work very well and I had that head pressure it got much worse when she increased the dose, she switched me to Celexa, which is very easy to do as they're almost the same drug. The Celexa didn't work either much, but it didn't have that head pressure side effect. What you haven't said is if this is a new problem or an old one, and if it has a trigger, some dramatic event that happened that brought this on. Anxiety disorders usually occur in the mid-twenties, not at 72. There are a host of life changes and biological changes that could have caused you to feel this now if it's new, and maybe medication isn't the only way to deal with it.