Would you add tolvaptan to manage difficult to treat SIADH in a patient who is already on high doses of sodium chloride tablets and urea but fails to reach adequate serum sodium levels?

First of all, I am NOT a fan of salt tablets for SIADH; it takes a bit over 7 one-gram salt tablets to equal the mmol supplied by a single 15-gram packet of urea.

And that many (large) pills can be nauseating, much more so than urea.

By far, I would prefer tolvaptan over urea, but tolvaptan is often...

Yes. If a patient's hyponatremia fails to improve on high doses of NaCl tablets and urea, I would add tolvaptan to increase urinary electrolyte-free water clearance. In a patient with a very high urinary [Na + K]/plasma [Na] ratio, tolvaptan is often needed to increase urinary electrolyte-free water...

If you're only increasing solute without adding a loop diuretic at the minimal dose required to suppress the tubular concentrating capacity and keep urine osmolality around 300, then fluid restriction alone, along with high solute intake, might not be enough.

Monitor the effect of the loop diuretic ...

I use tolvaptan a lot since it is now generic and no longer costs $$$$. Insurances often cover it with PA if started in hospital. I stop salt tablets , rx 30 tolvaptan 30 mg pills and have patient break in half and take 1/2 pill every other day and it’s usually sufficient and patients don’t have to ...