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Home / Conditions / Type 2 Diabetes / Joslin’s Diabetes Deskbook, Updated 2nd Ed., Excerpt #50: Pharmacotherapy of Type 2 Diabetes, Part 9

Joslin’s Diabetes Deskbook, Updated 2nd Ed., Excerpt #50: Pharmacotherapy of Type 2 Diabetes, Part 9

Richard S. Beaser, MD

Joslin_Diabetes_Deskbook

This week’s excerpt covers the following topics:

  • What drugs block glucose absorption
  • How to titrate this class of drugs
  • Learn the contraindications and precautions for the glucose blocking drugs
  • Discover which other drugs can cause serious side effects when used with drugs that block glucose absorption  

 

MEDICATIONS THAT BLOCK GLUCOSE ABSORPTION

3. α-GLUCOSIDASE INHIBITORS
 
Class Summary:
  • Action: competitive, reversible inhibitors of intestinal brush border α-glucosidase enzymes, which leads to delayed glucose absorption from the gastrointestinal tract and a lowering of postprandial hyperglycemia.
  • Required for efficacy: some remaining insulin secretory capacity by the pancreas
  • Manifestation on glucose patterns: reduces elevations of postprandial glucose levels
  • Potential effect on A1C: <0.5%–1%
  • Significant side effects: Flatulence, which is usually mild and self-limited, or diarrhea
  • Other side effects of note: rare elevations of liver transaminases
  • Typical patient with optimal efficacy: early type 2 diabetes with significant postprandial hyperglycemia
  • Contraindications: inflammatory bowel disease, colon ulceration, intestinal obstruction, significant renal disease (creatinine >2.0 mg/dl)
  • Other Effects:
    • Weight: minimal increase
    • Lipids: negligible

INDIVIDUAL MEDICATION SUMMARIES

A. ACARBOSE (GENERIC)
 
Brand name: Precose 
  • Indications: Monotherapy or in combination with a sulfonylurea, metformin, or insulin
  • Pharmacology:
    • Less than 2% absorbed
    • Most excreted in the feces. A few metabolites are absorbed and are excreted in the urine.
    • Metabolized in the GI tract by intestinal bacteria
  • Typical starting dose:
    • 25 mg orally given TID with the first bite of each meal
    • Can titrate more slowly based on clinical need or side effects, starting with 25 mg once daily, and then increasing to 25 mg TID
  • Typical dose titration pattern:
    • 25 mg TID, adjusted upward every 4 to 8 weeks to a maximum of 100 mg TID
    • Can start with lower dose and/or frequency for milder effect or to reduce likelihood of adverse symptoms
  • Optimal dose:
    • Depends on clinical effect and side effects, but usually 50–100 mg TID
    • Maximum dose:
      • Weight less than 60 kg: 50 mg TID
      • Weight more than 60 kg: 100 mg TID
  • Tablet size:
    • 25 mg, 50 mg, 100 mg
  • Drug interactions:
    • May affect bioavailability of digoxin and require a dose adjustment of digoxin
    • Intestinal adsorbents (charcoal) and digestive preparations may reduce the effect
    • Drugs that potentiate hyperglycemia: thiazides, other diuretics, corticosteroids, phenothiazines, thyroid products, estrogens, oral contraceptives, phenytoin, nicotinic acid, sympathomimetics, calcium channel blockers, and isoniazid
  • Contraindications and precautions:
    • Contraindications with known hypersensitivity to the drug and in the treatment of diabetic ketoacidosis
    • Contraindicated in patients with inflammatory bowel disease or other significant bowel, intestinal, or digestive conditions
    • Doesn’t usually cause hypoglycemia
    • Can cause transient elevations of serum transaminase levels
    • Pregnancy: category B — use only if clearly needed
  • Key advice to patients:
    • Take only 3 times daily.
    • Discuss side effects and the possibility of adjusting titration schedule if side effects are excessive.
    • Hypoglycemia treatment: Hypoglycemia may occur with use of these medications, particularly in combination with a medication that increases insulin levels. Keep in mind that these medications will delay the absorption of glucose that is consumed in the form of complex carbohydrates. Hypoglycemia must therefore be treated with a form of glucose (e.g., glucose tablets) rather than a complex form of carbohydrate.

B. MIGLITOL (GENERIC)

Brand name: Glyset
  • Indications: Monotherapy or in combination with a sulfonylurea
  • Pharmacology:
    • Absorption depends on dose: 25-mg dose: 100% absorbed; 100-mg dose: 50%–75% absorbed. Absorption is not involved in therapeutic effect
    • Metabolism: not metabolized
    • Excretion: mostly renal as unchanged drug
  • Typical starting dose:
    • 25 mg orally given TID with the first bite of each meal
    • Can titrate more slowly based on clinical need or side effects, starting with 25 mg once daily, and then increasing to 25 mg TID
  • Typical dose titration pattern:
    • 25 mg TID, adjusted upward every 4 to 8 weeks to a maximum of 100 mg TID
    • Can start with lower dose and/or frequency for milder effect or to reduce the likelihood of adverse symptoms
  • Optimal dose:
    • Depends on clinical effect and side effects, but usually 50–100 mg TID
    • Maximum dose: 100 mg TID
  • Tablet size:
    • Tablet size: 25 mg, 50 mg, 100 mg
  • Drug interactions:
    • Drugs that potentiate hyperglycemia: thiazides, other diuretics, corticosteroids, phenothiazines, thyroid products, estrogens, oral contraceptives, phenytoin, nicotinic acid, sympathomimetics, calcium channel blockers, and isoniazid
    • Intestinal adsorbents (charcoal) and digestive preparations may reduce the effect
  • Contraindications and precautions:
    • Contraindications with known hypersensitivity to the drug
    • Treatment of diabetic ketoacidosis
    • Contraindicated in patients with inflammatory bowel disease or other significant bowel, intestinal, or digestive conditions
    • Doesn’t usually cause hypoglycemia
    • Can cause transient elevations of serum transaminase levels
    • Do not use in patients with a creatinine level >2.0 mg/dl
    • Pregnancy: category B — use only if clearly needed
    • Key advice to patients:
      • Take only TID.
      • Discuss side effects and the possibility of adjusting titration schedule if side effects are excessive.
      • Hypoglycemia Treatment: Hypoglycemia may occur with use of these medications, particularly in combination with a medication that increases insulin levels. Keep in mind that these medications will delay the absorption of glucose that is consumed in the form of complex carbohydrates. Hypoglycemia must therefore be treated with a form of glucose (e.g., glucose tablets), rather than a complex form of carbohydrate.

EDUCATION SUMMARIES

IMPORTANT NOTE: These Summaries are provided for the convenience of the reader, for general education purposes, and as a clinical guide only. They reflect the author’s compilation of information and general usage patterns that were accurate at the time of manuscript preparation. They should not be a substitute for the latest package insert. All categories listed below, particularly indications, precautions, screening recommendations, side effects, and other usage recommendations are subject to change without notice. For expected effects on A1C levels based on published data, be aware that some studies may reflect change with respect to placebo or change with respect to baseline. A1C improvements are also usually greater in magnitude with a higher starting value, and studies often vary with respect to the initial A1C of the treatment groups. Drug interactions listed are only those with specific relationship to the medication(s) in question, and do not list the many medications that might generally increase or decrease glucose levels. Ultimately, clinicians should use these medications based on the latest available information in the package insert, and not the potentially dated information in these Summaries.

Next Week Part 10: MEDICATIONS THAT INCREASE INSULIN SECRETION

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Please Note: Reasonable measures have been taken to ensure the accuracy of the information presented herein. However, drug information may change at any time and without notice and all readers are cautioned to consult the manufacturer’s packaging inserts before prescribing medication. Joslin Diabetes Center cannot ensure the safety or efficacy of any product described in this book.

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