SIADH Treatment Options
1. Treat underlying cause of SIADH: Pain, Primary lung pathology, Post-operative phenomenon, Medications, Basically anything
2. Free water restriction
 • All food has water
 • Electrolyte Free Water Clearance (EFWC) Equation
 • For practical purposes, restrict to 1 to 1.5L per day (if you plan on using this as a long-term solution, you should prove feasibility during hospitalization)
3. Salt tabs
 • Start with lg NaCl PO TID
 • With lower Na, you should increase the number and frequency of salt tablets administered
 • This can cause volume overload
4. Urea powder
 • Induces osmotic water elimination by promoting passive sodium reabsorption in the ascending limb of the loop of Henle
 • Contraindicated in cirrhosis given the potential for it to be metabolized into ammonium by urease-producing bacteria in the colon
5. 0.9% NS
 • If Urine osmolality < 538 AND UNa + UK < 154, can try giving 0.9% NS
 • Give 250 cc NS boluses at a time
 • Re-check the serum Na+ in 2-4 hours and decide before giving more
6. Vasopressor receptor antagonists (-vaptans)
 • Blocks ADH receptor
 • Major side effects: Thirst, Nausea, Hypotension, Increased urine output

Satya Patel, MD @SatyaPatelMD

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