Why am I still experiencing dark urine and infrequent urination despite taking Pedialyte (electrolyte replenisher) for diabetes insipidus?

You Do Not Have Diabetes Insipidus

Based on your symptoms—dark urine, infrequent urination (only 5 times since morning), and low fluid intake (28 oz water)—you are experiencing simple dehydration, not diabetes insipidus. If you had diabetes insipidus, Pedialyte would not suppress your symptoms; you would continue to produce large volumes of dilute urine (typically >3 liters/day in adults) regardless of what you drink, and you would experience relentless, unquenchable thirst driving you to consume massive amounts of fluid 1, 2.

Why Your Symptoms Rule Out Diabetes Insipidus

Patients with true diabetes insipidus cannot reduce their urine output by limiting fluid intake. The hallmark of diabetes insipidus is the kidney's inability to concentrate urine due to either ADH deficiency (central DI) or kidney resistance to ADH (nephrogenic DI), resulting in continuous production of large volumes of inappropriately dilute urine (osmolality <200 mOsm/kg) even when dehydrated 1, 3, 4.

Your current presentation demonstrates the opposite:

• Reduced urination frequency: 5 voids since morning indicates your kidneys are appropriately concentrating urine in response to limited fluid intake 2
• Dark urine: This reflects concentrated urine with high osmolality, which is physiologically normal when fluid intake is inadequate 5
• Low fluid intake: Only 28 oz (approximately 830 mL) of water is insufficient for daily needs, and your body is appropriately conserving water 2

The Pedialyte Misconception

You are correct that Pedialyte does not treat diabetes insipidus—but you don't have diabetes insipidus. Pedialyte contains approximately 1,035 mg of sodium per liter, representing a substantial electrolyte load 2. When you consumed Pedialyte over 24 hours ago, you likely temporarily increased your fluid intake, which improved your hydration status. Now that you've returned to inadequate fluid intake (28 oz), you've become dehydrated again.

In true diabetes insipidus:

• Patients produce 3-20+ liters of urine daily regardless of fluid type consumed 1, 2, 4
• The intact thirst mechanism drives patients to drink massive volumes continuously to compensate for urinary water losses 2
• Patients experience relentless thirst and seek cold water constantly 4
• Limiting fluid intake leads to dangerous hypernatremia (serum sodium >145 mmol/L) and life-threatening dehydration 2, 6

What You're Actually Experiencing

Your symptoms represent normal physiological dehydration from inadequate fluid intake. The recommended daily fluid intake for adults is approximately 2-3 liters (68-102 oz), and you've consumed less than one-third of this amount 2. Your kidneys are functioning normally by:

• Concentrating urine (producing dark color) to conserve water 5
• Reducing urine frequency to prevent further fluid loss 2
• Maintaining appropriate water balance given your limited intake 2

Immediate Action Required

Increase your fluid intake immediately to at least 2-3 liters (68-102 oz) of plain water daily, spread throughout the day. Monitor your urine color—it should become pale yellow within 24-48 hours of adequate hydration 5. If dark urine persists despite drinking 2-3 liters daily, or if you develop additional symptoms (fever, muscle pain, weakness), seek medical evaluation to rule out other conditions such as rhabdomyolysis, liver dysfunction, or urinary tract pathology 7, 5.

Red Flags That Would Suggest Diabetes Insipidus

Seek immediate medical evaluation if you experience 1, 2, 3:

• Polyuria: Urinating >3 liters (>100 oz) per 24 hours despite normal fluid intake
• Unquenchable thirst: Constant, intense thirst that drives you to drink continuously, often preferring ice-cold water
• Nocturia: Waking multiple times nightly to urinate large volumes (described by parents of affected children as "bed flooding")
• Hypernatremia symptoms: Confusion, weakness, seizures, or altered mental status
• Inability to concentrate urine: Persistently pale, water-like urine regardless of hydration status

Your current symptoms do not meet any of these criteria and instead reflect straightforward dehydration from inadequate fluid intake.