Taking medicine on tsha ba av

If I take medicine regularly in the morning, can i take it on tsha ba av?

Yes. Even if not regularly.

Can you take without water? If not a lukewarm small amount of sink water is permitted. (lukewarm - because hot or cold is refreshing)

How much water can I use to take the medicine on Yom Kippur and other fasts?

as lttle as`possible that you still swallow the pill. never more 1-1/2 ounces