Oral glucose, also known as dextrose, is a simple, fast-acting sugar administered by mouth for two primary medical purposes. It is absorbed rapidly from the digestive tract into the bloodstream, making it highly effective for quickly raising low blood sugar levels. Glucose administration is most commonly used in an emergency setting to treat hypoglycemia, or low blood sugar, or in a controlled clinical environment as part of a diagnostic test to evaluate a person’s metabolic response to a sugar load.
Administering Glucose for Hypoglycemia
Hypoglycemia, or low blood sugar, typically occurs when blood glucose drops below 70 milligrams per deciliter (mg/dL) for people with diabetes. It requires immediate intervention to prevent severe symptoms like confusion, seizures, or loss of consciousness. The most common and standardized approach for treating mild to moderate hypoglycemia is known as the “15-15 rule,” which is designed to be self-administered by the affected individual or a caregiver.
The first step involves consuming 15 grams of a fast-acting carbohydrate source, such as glucose tablets, gel, or a half-cup of fruit juice or regular soda. Foods containing fat or protein, like chocolate or nuts, should be avoided because they slow down sugar absorption. After the rapid carbohydrate is consumed, a 15-minute waiting period allows the glucose to enter the bloodstream and begin raising the blood sugar level.
Following the wait, the individual must recheck their blood glucose level. If the reading is still below 70 mg/dL, the entire process is repeated: another 15 grams of fast-acting carbohydrate is consumed, followed by another 15-minute wait and retest. This cycle continues until the blood sugar returns to a safe range. Once stable, a small meal or snack containing protein and a longer-acting carbohydrate is recommended if the next scheduled meal is more than an hour away.
Oral Glucose Tolerance Testing Procedure
Oral glucose is also administered in a highly controlled medical setting for the Oral Glucose Tolerance Test (OGTT), a diagnostic tool used to check how quickly the body clears glucose from the blood. This procedure is used to diagnose conditions like prediabetes, type 2 diabetes, and gestational diabetes. The patient must fast for at least eight to twelve hours before the test to establish a baseline blood glucose level.
The test begins with a fasting blood draw, after which a standardized dose of glucose solution is administered. For most adults, this dose is 75 grams of anhydrous glucose dissolved in water, which must be consumed quickly, typically within five minutes. This precise, measured dose ensures a consistent stimulus to the body’s glucose-regulating mechanisms.
After the glucose solution is consumed, the patient must remain sedentary and continue fasting for the duration of the test. Additional blood samples are drawn at specific timed intervals, most commonly at one and two hours after the glucose drink. In some protocols, blood may be drawn at more frequent intervals or for a longer duration, up to three or five hours, to monitor the full glucose response curve.
Available Forms and Products
The physical forms of oral glucose are designed to prioritize rapid and convenient ingestion, which is crucial for treating hypoglycemia. Products specifically formulated for this purpose include chewable glucose tablets and glucose gels, which provide precise, pre-measured amounts of pure glucose. These specialized forms are easy to carry and offer a controlled dose to avoid overtreating low blood sugar.
Common household items can also serve as a source of rapid oral glucose, offering flexibility in an emergency. These items typically contain about 15 grams of carbohydrates.
Household Sources
- Four ounces of fruit juice (e.g., apple or orange juice).
- Regular (non-diet) soda.
- One tablespoon of table sugar dissolved in water.
- One tablespoon of honey dissolved in water.
While these household items are effective, specific glucose products provide the most reliable and fastest source of simple sugar.
Safety and Contraindications
Administering oral glucose requires careful consideration of a person’s ability to swallow. The primary contraindication is a compromised airway or the inability to safely swallow, which often occurs if the patient is unconscious, seizing, or has an altered mental status. In these situations, attempting to give any liquid or solid by mouth carries a high risk of aspiration, where the substance enters the lungs.
If a person experiencing hypoglycemia is unresponsive or unable to swallow, oral glucose should not be given, and emergency medical services must be called immediately. Caregivers should be prepared to use an emergency glucagon injection, as this is the standard treatment when a person cannot take sugar by mouth. Even when using a thick glucose gel, caution is necessary, and the substance should be placed between the cheek and gum for absorption to minimize aspiration risk.