What is the demeclocycline dosage mentioned in the management plan?

• A. 1200 mg/day
• B. 600 mg/day
• C. 2400 mg/day
• D. 300 mg/day

Answer: (A)

Demeclocycline is used in SIADH to counteract the action of ADH on the kidney, promoting water excretion and helping to correct hyponatremia. In practice, a daily dose around 1200 mg is commonly chosen because it provides enough anti-ADH effect to impact water reabsorption while keeping the risk of adverse effects manageable. This dose is typically given in divided portions (for example, 600 mg twice daily). Doses substantially lower may not reliably achieve the desired effect, while much higher doses increase the risk of nephrotoxicity, phototoxicity, and other tetracycline-related side effects. Therefore, 1200 mg per day best aligns with achieving therapeutic benefit with acceptable safety in the management plan.