Glyset (miglitol) is an alpha-glucosidase inhibitor specifically formulated to manage blood glucose levels in adults with type 2 diabetes mellitus. It functions by delaying the digestion of carbohydrates in the small intestine, thereby reducing the postprandial rise in blood glucose. This oral anti-diabetic agent is typically prescribed as an adjunct to diet and exercise, and may be used alone or in combination with other glucose-lowering medications such as sulfonylureas or metformin. Its targeted mechanism offers a complementary approach to glycemic management, particularly for patients struggling with post-meal glucose spikes. Clinical use requires careful patient selection and monitoring to align with individualized treatment goals.

Features

• Active ingredient: Miglitol 25 mg, 50 mg, or 100 mg tablets
• Pharmacologic class: Alpha-glucosidase inhibitor
• Delays carbohydrate digestion in the small intestine
• Reduces postprandial hyperglycemia
• Does not cause hypoglycemia when used as monotherapy
• Minimal systemic absorption; acts locally within the GI tract
• Requires administration with the first bite of each main meal

Benefits

• Effectively lowers postprandial blood glucose levels, reducing HbA1c by approximately 0.5–1.0%
• Minimizes risk of hypoglycemia compared to insulin secretagogues when used as monotherapy
• Provides complementary mechanism of action for combination therapy regimens
• Does not promote weight gain—may support weight neutrality or modest loss
• May reduce glycemic variability and oxidative stress associated with glucose fluctuations
• Suitable for elderly patients and those with renal impairment (with dosage adjustment)

Common use

Glyset is indicated as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus. It is particularly useful in patients who experience significant postprandial hyperglycemia despite dietary modifications. Clinicians often prescribe miglitol for individuals who cannot tolerate metformin or sulfonylureas, or as part of a combination regimen when monotherapy provides insufficient glycemic control. It may also be selected for patients where weight gain or hypoglycemia risk are significant concerns with other agents.

Dosage and direction

The recommended starting dosage of Glyset is 25 mg orally three times daily, taken with the first bite of each main meal. Dosage may be titrated upward at 4–8 week intervals based on tolerability and glycemic response. The maintenance dosage is typically 50 mg three times daily, though some patients may benefit from 100 mg three times daily. Maximum recommended dosage is 100 mg three times daily. Tablets should be swallowed whole with a small amount of liquid. Dose adjustment is recommended in patients with renal impairment (creatinine clearance <25 mL/min); use is not recommended when creatinine clearance is <25 mL/min.

Precautions

Glyset should be used with caution in patients with inflammatory bowel disease, colonic ulceration, or partial intestinal obstruction due to its local gastrointestinal effects. Renal function should be assessed before initiation and periodically during treatment. Patients should be educated about the management of potential gastrointestinal side effects, which often diminish with continued use. Hypoglycemia may occur when Glyset is used in combination with insulin or insulin secretagogues; in such cases, glucose (dextrose) must be used for treatment rather than sucrose (table sugar), as sucrose hydrolysis is inhibited. Periodic monitoring of hepatic enzymes is advised though clinically significant hepatotoxicity is rare.

Contraindications

Glyset is contraindicated in patients with known hypersensitivity to miglitol or any component of the formulation. It should not be used in patients with diabetic ketoacidosis, inflammatory bowel disease, colonic ulceration, or chronic intestinal diseases associated with marked disorders of digestion or absorption. It is contraindicated in patients with conditions that may deteriorate as a result of increased gas formation in the intestine. Use is not recommended in patients with severe renal impairment (creatinine clearance <25 mL/min).

Possible side effects

The most common adverse reactions are gastrointestinal and include flatulence (41.5%), diarrhea (28.7%), and abdominal pain (11.7%). These effects are generally dose-related and often diminish in frequency and intensity with continued treatment. Other reported side effects include rash (4.3%) and transient elevations of serum transaminases. Hypoglycemia may occur when used in combination with other antidiabetic agents. Rare cases of pneumatosis cystoides intestinalis have been reported with alpha-glucosidase inhibitors.

Drug interaction

Glyset may reduce the bioavailability of digoxin, ranitidine, and propranolol—monitoring and potential dosage adjustment may be necessary. It may diminish the hypoglycemic effect of digestive enzyme preparations containing carbohydrate-splitting enzymes (e.g., amylase, pancreatin). Intestinal adsorbents (e.g., charcoal) and digestive enzyme preparations may reduce the effectiveness of Glyset and should not be taken concomitantly. When used with sulfonylureas or insulin, the risk of hypoglycemia increases—appropriate monitoring and dose adjustment of these agents may be required.

Missed dose

If a dose is missed, it should be skipped entirely if it is nearly time for the next scheduled dose. Do not double the dose to make up for a missed administration. Patients should be advised to take Glyset with the first bite of each main meal for optimal efficacy. If a meal is skipped, the corresponding dose should be omitted.

Overdose

There is no experience with acute overdose of Glyset. Excessive doses may increase the severity of gastrointestinal symptoms such as flatulence, diarrhea, and abdominal discomfort. Hypoglycemia has not been observed with miglitol monotherapy overdose. In cases of suspected overdose, symptomatic and supportive treatment should be initiated. Since miglitol is not significantly metabolized and is excreted renally, dialysis may be considered in cases of significant overdose, particularly in patients with renal impairment.

Storage

Store Glyset tablets at controlled room temperature, 20–25°C (68–77°F), with excursions permitted between 15–30°C (59–86°F). Keep the container tightly closed and protect from moisture. Keep out of reach of children and pets. Do not use beyond the expiration date printed on the packaging.

Disclaimer

This information is provided for educational purposes only and does not constitute medical advice. Glyset should be used only under the supervision of a qualified healthcare provider. Individual response to medication may vary. Patients should not initiate, discontinue, or change dosage without consulting their physician. The full prescribing information should be consulted before initiating therapy.

Reviews

Clinical studies demonstrate that Glyset effectively reduces postprandial glucose excursions and HbA1c levels by 0.5–1.0% when used as monotherapy or in combination with other antidiabetic agents. In a 1-year multicenter trial, miglitol 100 mg three times daily reduced HbA1c by 0.9% compared to placebo. Gastrointestinal side effects were common but often transient, with discontinuation rates of approximately 10–15% in clinical trials. Many clinicians note its particular value in targeting postprandial hyperglycemia without causing weight gain or significant hypoglycemia when used appropriately. Long-term data suggest sustained efficacy with continued use, though individual tolerance varies.