Miglitol

• Type 2 Diabetes
• Postprandial Hyperglycemia
• Glycemic Control

Miglitol is an alpha-glucosidase inhibitor used to improve glycemic control in adults with type 2 diabetes mellitus. By delaying carbohydrate digestion and absorption, miglitol helps reduce postprandial blood glucose spikes, making it a useful adjunct to diet and lifestyle modifications.

Mechanism of Action

Miglitol works by reversibly inhibiting membrane-bound intestinal alpha-glucosidases:

• Maltase-glucoamylase: Breaks down maltose and starch
• Sucrase-isomaltase: Breaks down sucrose and branched starches
• Glucoamylase: Breaks down starch

By blocking these enzymes, miglitol delays the digestion of complex carbohydrates and sucrose into absorbable monosaccharides (glucose and fructose). This results in slower glucose absorption, reduced postprandial glucose peaks, and lower overall glycemic excursions. Unlike sulfonylureas or insulin, miglitol does not cause hypoglycemia when used as monotherapy.

Available Formulations

Miglitol is available as oral tablets:

• 25 mg tablets
• 50 mg tablets
• 100 mg tablets

Tablets should be taken at the start (first bite) of each main meal.

Medical Uses

FDA-Approved Indication:

• Adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus

May be used as:

• Monotherapy when diet alone is inadequate
• Combination therapy with sulfonylureas when diet plus either drug alone does not provide adequate control

Dosing Guidelines

Starting Dose:

• 25 mg three times daily at the start of each main meal

Titration:

• After 4-8 weeks, may increase to 50 mg three times daily
• After additional 3 months, may increase to 100 mg three times daily if needed

Maximum Dose:

• 100 mg three times daily

Gradual dose titration helps minimize gastrointestinal side effects.

Important Safety Information

Contraindications:

• Diabetic ketoacidosis
• Inflammatory bowel disease
• Colonic ulceration
• Partial intestinal obstruction or predisposition to obstruction
• Chronic intestinal diseases with marked disorders of digestion or absorption
• Conditions that may deteriorate with increased intestinal gas
• Hypersensitivity to miglitol

Warnings and Precautions:

• GI side effects are common initially but usually decrease over time
• May affect absorption of other drugs
• Serum transaminase monitoring recommended
• Not for type 1 diabetes or diabetic ketoacidosis

Drug Interactions

• Digoxin: Miglitol may reduce digoxin bioavailability
• Propranolol: Bioavailability significantly reduced
• Ranitidine: Bioavailability significantly reduced
• Intestinal adsorbents (charcoal) and digestive enzyme preparations: May reduce miglitol effect

Special Populations

• Renal Impairment: Not recommended if creatinine clearance <25 mL/min (drug accumulates)
• Hepatic Impairment: No dose adjustment needed (minimal hepatic metabolism)
• Elderly: No specific dose adjustment; use with caution
• Pediatric: Safety and efficacy not established
• Pregnancy: Category B; use only if clearly needed

Hypoglycemia Management

When miglitol is used with sulfonylureas or insulin, hypoglycemia may occur. Important considerations:

• Sucrose (table sugar) cannot be used to treat hypoglycemia (digestion is blocked)
• Must use glucose (dextrose) tablets or gel to treat hypoglycemia
• Patients should carry glucose tablets at all times