Many prescribed meds cause dehydration, and the sort of meds I'm thinking of are not the sort that cause increased urine output, such as diuretics. I'm thinking of the ones that increase thirst because they cause the body, principally in its blood vessels, to retain too much salt/sodium, along with the water which sodium attracts to itself. Over time these meds impair the efficiency of the kidneys. Paradoxically, in fact, these meds reduce urine output, rather than increase it, and so, often, this problem may be misdiagnosed as urinary retention.
What are these meds? you may be wondering. - Well they are the drugs I frequently warn about on my website and in my blogs, namely most antidepressants, many prescribed steroids and HRT, anti-psychotics, anti-convulsants, NSAID painkillers and others.
By the time you feel thirsty, you are already dehydrated. And you may unwittingly increase the problem by drinking, say, coffee, which is widely considered to have diuretic properties. Alcohol too is a diuretic. If you are thirsty, you would be much better slaking your thirst with plain water. Salty drinks are clearly inadvisable, and sugary drinks also tend to increase thirst. You are not in need of vague 'liquid'; you are specifically in need of PLAIN WATER.
So a major, rather strange, consequence of taking these dangerous, over-prescribed drugs, is that while taking them you tend to be chronically thirsty (particularly if taking a high dose), and chronically in a state of dehydration, yet carrying around with you a lot of excess water, mainly in your blood vessels, particularly in your poor, over-stretched, weakened, increasingly painful veins. See my website for helpful information and suggestions relating to these problems.