Yes. They are somewhat nephrotoxic and can impair renal function. As a rule, you want to ensure that the snake is taking fluids...soaking is an easy way, but sometimes tubing is appropriate. Again, I still question the idea of getting the humidity as low as possible, for the reasons I outlined previously...but since I have not even seen this particular snake, I have no choice but to defer to the vet's judgement. If the snake is bubbling over, so to speak (relatively thin, clear secretions, with bubbles...that are visible at the snakes mouth, and may drip/dribble out), it may be temporarily appropriate; but remember that they are a tropical species and basic husbandry requires maintenance of moderate humidity. Dry it out too much and you will end up with problems.