Yes, don't know what if any meds you're taking, but some can certainly give a dry mouth. Not to scare you, but feeling thirsty a lot is also a symptom of diabetes (maybe other things too, i don't know) - best to tell your doc and get it checked out).
You can always ring NHS Direct: 0845 4647 to ask them, though they'll probably end up telling you to see your doctor too!
I can taste metal all the time when I'm not on medication??? I drink lot's of water and juice but still I can taste it and I'm really conscious of my tongue touching my back teeth