Is there a prescription drug that increases blood sodium level?
Yes, it’s called the American diet
Is there a prescription drug that increases blood sodium level?
The vaptans (as mentioned above) absolutely can, given they're ADH antagonists used to treat hyponatremia.
Less obviously, most diuretics typically will not, as you lose more sodium than you do water. The major exception here would be osmotic diuretics- mannitol for example will initially lower the sodium but will ultimately increase it as you pee it all out.
The other big one to think about is that some drugs can give you nephrogenic DI. The major bad actor here is Lithium, which is probably the most common prescription medication that can cause hypernatremia. The other stuff above (with the exception of salt) is fairly rarely used.
Furosemide *can* through compensatory mechanisms if you truly dehydrate yourself, but more commonly actually causes hyponatremia.Furosemide can as well!