http://revach.net/article.php?id=1393

Section: Halacha   Category: Tshuvos
Rav Shlomo Zalman Auerbach: Just Relax and Take Your Medicine Without Making a Bracha on the Water
The Halacha is that you only make a bracha on water if you are thirsty.  If you drink water to clear your throat you do not make a bracha.  What happens if a person drinks water to take a pill?  Maybe he is thirsty also and will drink more than the minimum needed for the pill.  Then part of the water is for his thirst.  Some recommend to make a bracha and drink a bit of water before taking the pill so that it is not a bracha l'vatala.

Rav Shlomo Zalman said that this is nonsense.  You do not need to worry that you might be thirsty as well.  Furthermore you do not need to worry about drinking more that the minimum needed for the pill.  (Aleihu Lo Yibol OC 141)

Disclaimer: We try to convey the Tshuva to the best of our ability. We admit that our understanding may not be accurate. Please also understand that this Tshuva may not be the final word on this topic. One should consult a Rav before drawing any conclusions.