Miglitol

Approved Indications

• Type 2 Diabetes Mellitus (T2DM):
  Miglitol is indicated as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus. It is especially effective in reducing postprandial hyperglycemia.
• It may be used as monotherapy or in combination with other antidiabetic agents such as sulfonylureas, metformin, or insulin.

Off-label or Clinically Accepted Uses

• Impaired Glucose Tolerance (IGT) / Prediabetes:
  Occasionally used off-label to slow progression from impaired glucose tolerance to overt type 2 diabetes.
• Polycystic Ovary Syndrome (PCOS):
  Used off-label to manage hyperinsulinemia and insulin resistance in women with PCOS.

Adults

• Initial Dose:
  25 mg orally three times daily (TID) at the start of each main meal.
• Titration:
  After 4–8 weeks, the dose may be increased based on 1-hour postprandial glucose response.
• Maintenance Dose:
  50 mg or 100 mg TID.
• Maximum Dose:
  100 mg TID.

Pediatric Use

• Not recommended. Safety and efficacy have not been established in individuals under 18 years of age.

Elderly

• Same dosing as adults.
  Use with caution due to potential age-related decline in renal function.

Renal Impairment

• Contraindicated in patients with significant renal impairment (serum creatinine >2.0 mg/dL or CrCl <25 mL/min).
  Miglitol is renally excreted unchanged.

Hepatic Impairment

• No dose adjustment necessary.
  Miglitol is not hepatically metabolized.

Administration Notes

• Tablets should be taken at the first bite of each main meal.
• If a meal is skipped, that dose should be omitted.

Miglitol is a competitive and reversible inhibitor of intestinal alpha-glucosidase enzymes (including sucrase, maltase, and isomaltase). These enzymes hydrolyze complex carbohydrates into absorbable monosaccharides. By inhibiting their activity, miglitol delays the digestion and absorption of carbohydrates in the small intestine, thereby blunting postprandial blood glucose spikes. Unlike sulfonylureas, miglitol does not stimulate insulin secretion and does not cause hypoglycemia when used alone.

• Absorption: Rapidly absorbed in the upper small intestine; oral bioavailability ranges from 50–100%.
• Time to Peak Concentration (Tmax): 2 to 3 hours
• Distribution: Volume of distribution ≈ 0.18 L/kg; negligible protein binding
• Metabolism: Not metabolized
• Excretion:
• ~95% excreted unchanged in urine
• Elimination half-life: 2 to 3 hours

• Pregnancy: Former FDA Category B
  Animal studies have not shown fetal harm. However, there are no adequate, well-controlled studies in pregnant women. Use only if clearly needed.
• Lactation:
  It is not known whether miglitol is excreted into human breast milk. Caution is advised if used during breastfeeding due to the theoretical risk of GI side effects in the infant.

• Primary Class: Alpha-glucosidase Inhibitor
• Subclass: Oral antihyperglycemic agent

• Hypersensitivity to miglitol or any component of the formulation
• Inflammatory bowel disease (e.g., ulcerative colitis, Crohn’s disease)
• Intestinal obstruction or predisposition to intestinal obstruction
• Chronic intestinal diseases with marked digestive or absorptive disorders
• Significant renal impairment (serum creatinine >2.0 mg/dL or CrCl <25 mL/min)

• Gastrointestinal Effects: Flatulence, abdominal pain, and diarrhea are common due to undigested carbohydrates fermenting in the colon.
• Hypoglycemia Risk: Miglitol does not cause hypoglycemia alone, but may increase the risk when used with insulin or sulfonylureas. Hypoglycemia should be treated with glucose (dextrose), not sucrose.
• Renal Monitoring: Assess renal function before and during therapy in at-risk patients.
• No Hepatic Metabolism: Liver function tests are not required for routine monitoring.

Common Side Effects (mostly gastrointestinal):

• Flatulence
• Abdominal pain
• Diarrhea
• Bloating

Less Common Side Effects:

• Nausea
• Constipation
• Elevated hepatic transaminases (rare)

Rare but Serious Side Effects:

• Intestinal obstruction (very rare)
• Hypoglycemia (when combined with insulin/sulfonylureas)
• Hepatic dysfunction (extremely rare)

Note: GI effects are usually dose-related and tend to subside with continued use.

• Sulfonylureas/Insulin: Increased risk of hypoglycemia. Use caution.
• Digestive enzymes (e.g., amylase, pancreatin): May reduce miglitol efficacy.
• GI-acting agents: Adsorbents and motility modifiers may interfere with action or tolerability.
• Alcohol: May worsen GI side effects.

Metabolic Interactions:

• Miglitol is not metabolized by CYP450 enzymes, so it has low potential for hepatic drug interactions.

• ADA 2024 Guidelines: Miglitol is considered a secondary option in the management of T2DM, with newer agents preferred due to better tolerability and cardiovascular outcomes.
• WHO 2023 Diabetes Guidelines: Miglitol remains an acceptable oral agent in resource-limited settings, particularly when postprandial control is a priority.

• Temperature: Store at 20°C to 25°C (68°F to 77°F)
• Humidity & Light: Protect from moisture and heat; store in a tightly closed container
• Handling: Do not freeze
• Reconstitution: Not applicable; no refrigeration required