How much dextrose is in 100 mL of D5W?

December 4, 2025 •

2 min read

Dextrose 5% in Water, commonly abbreviated as D5W, is a standard intravenous solution used in medical settings worldwide. This solution contains 5 grams of dextrose in every 100 mL, a fact derived from its name and standard medical concentration conventions.

Quick Summary

D5W is a 5% dextrose solution, meaning it contains 5 grams of dextrose for every 100 mL of fluid. This straightforward calculation is fundamental for medical professionals when preparing and administering intravenous fluids for various patient needs. The solution provides a source of free water and calories.

Key Points

Dextrose Content: 100 mL of D5W contains 5 grams of dextrose, as indicated by the 5% concentration.
Basis of Measurement: The '5%' in D5W is a mass-to-volume ratio, meaning 5 grams per 100 milliliters.
Tonicity Shift: D5W is initially isotonic but becomes hypotonic in the body after the dextrose is metabolized.
Key Medical Uses: It is used for rehydration, as a medication diluent, and to treat mild hypoglycemia.
Caloric Value: One liter of D5W provides approximately 170 calories, offering minimal nutritional support.
Important Caution: Use of D5W requires careful monitoring, especially in patients with head injuries, due to the risk of fluid shifts.

Understanding D5W: The Basics

D5W, or Dextrose 5% in Water, is a common intravenous solution. The 5% indicates the concentration of dextrose, a simple sugar identical to glucose, dissolved in water. This percentage represents 5 grams of dextrose per 100 milliliters (mL) of solution.

The Calculation Explained

Determining the amount of dextrose in 100 mL of D5W is simple: it's 5 grams, as per the 5% concentration (5 grams per 100 mL). To calculate the dextrose content for other volumes, you use this ratio. For instance, 200 mL of D5W contains 10 grams of dextrose, and 1 liter (1000 mL) contains 50 grams.

Medical Applications of D5W

D5W has several medical uses, including hydration, often for patients with high sodium levels, use as a medication diluent, and management of mild low blood sugar. It provides minimal calories.

Physiological Effects and Considerations

D5W is initially isotonic but becomes hypotonic in the body as dextrose is metabolized. This can cause water to shift into cells, including brain cells. Therefore, D5W should be used cautiously in patients with head injuries or risk of increased intracranial pressure. Monitoring blood glucose and electrolytes is essential.

Comparison with Other IV Fluids

Comparing D5W with other common IV fluids highlights its specific uses:


Feature	D5W	Normal Saline (NS)	Lactated Ringer's (LR)
Composition	5% Dextrose in Water	0.9% Sodium Chloride (saltwater)	Sodium Chloride, Potassium Chloride, Calcium Chloride, Sodium Lactate
Caloric Value	~170 kcal per liter	0 kcal	0 kcal
Electrolyte Content	None	Sodium, Chloride	Sodium, Chloride, Potassium, Calcium
Initial Tonicity	Isotonic	Isotonic	Isotonic
In-body Effect	Becomes hypotonic after dextrose metabolism.	Stays isotonic.	Stays isotonic.
Primary Use	Free water replacement, diluent, mild hydration, some calorie provision.	Volume expansion, hydration, sodium replacement.	Aggressive fluid replacement, electrolyte replenishment, and alkalinizing agent.
Considerations	Risk of hyperglycemia and fluid shifts; avoid in head injuries.	Risk of hypernatremia and hyperchloremia with large volumes.	Risk of hyperkalemia in certain patients.

Conclusion

In conclusion, 100 mL of D5W contains 5 grams of dextrose. This solution is used for hydration, providing minimal calories, and as a medication carrier. Its shift from isotonic to hypotonic after dextrose metabolism requires careful monitoring. Understanding D5W's composition and effects is crucial for safe patient care.

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Frequently Asked Questions

D5W stands for Dextrose 5% in Water. It is a sterile intravenous solution that contains 5 grams of dextrose (glucose) dissolved in every 100 mL of pure water.

Initially, D5W is an isotonic solution in the IV bag. However, once administered, the dextrose is quickly metabolized by the body's cells for energy, leaving behind free water. This makes the remaining fluid effectively hypotonic in the body.

D5W is primarily used for hydration, providing free water to patients, particularly those with hypernatremia (high sodium levels). It also serves as a vehicle for administering other medications intravenously.

No, D5W does not provide significant nutritional support. While the dextrose provides a modest amount of calories (about 170 kcal per liter), it is primarily used for hydration and as a diluent, not as a primary source of nourishment.

No, D5W is not the best treatment for severe hypoglycemia. For a rapid and significant blood sugar increase, higher concentration dextrose solutions, such as D50W (50% dextrose in water), are typically used.

D5W must be used cautiously in patients with head injuries due to its hypotonic effect after the dextrose is metabolized. The free water can cause fluid shifts into brain cells, potentially increasing intracranial pressure.

Based on the 5% concentration (5 grams per 100 mL), you would calculate the amount of dextrose in 500 mL by multiplying 5 grams by 5 (since 500 mL is five times 100 mL). This results in 25 grams of dextrose.