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Home / Conditions / Type 2 Diabetes / Joslin’s Diabetes Deskbook, Updated 2nd Ed., Excerpt #43: Pharmacotherapy of Type 2 Diabetes, Part 2

Joslin’s Diabetes Deskbook, Updated 2nd Ed., Excerpt #43: Pharmacotherapy of Type 2 Diabetes, Part 2

Richard S. Beaser, MD

Joslin_Diabetes_Deskbook

This week’s excerpt covers the following topics:

  • The mechanism of action for antidiabetes medications
  • Which medications improve insulin action
  • Which meds slow gastric absorption
  • Which meds increase insulin secretion
  • Which meds increase the effect of incretins
  • How to compare diabetes meds
 

How the Various Antidiabetes Medications Work

Listed below are general summaries of how the antidiabetes diabetes medications work with respect to the various pathophysiological states that constitute type 2 diabetes.

Medications that improve insulin action

Classes: biguanides, thiazolidinediones

Efficacy with respect to insulin resistance: Reducing insulin resistance is the primary effect of these medications, whether that resistance is hepatic (primary action of the biguanide metformin) or peripheral (major action of the thiazolidinediones). Their clinical efficacy is dependent on the present degree of insulin resistance.

Efficacy with respect to insulin level: These medications can be effective as long as insulin is present, and that insulin may be of exogenous or endogenous origin. The key is just that insulin be present, and that there is some insulin resistance against which these medications can work. Therefore, in patients with type 2 diabetes and significant insulin resistance who also have significant loss of insulin secretory function, these medications could be effective along with either insulin secretagogues to stimulate endogenous insulin production, incretin mimetics, or replacement exogenous insulin therapy.

Medications that slow glucose absorption

Classes: α-glucosidase inhibitors

Efficacy with respect to insulin resistance: Any medication that reduces glucose levels decreases glucose toxicity and thus decreases insulin resistance. They have little or no direct effect on insulin resistance.

Efficacy with respect to insulin level: An early defect of type 2 diabetes is loss of first-phase insulin secretion. Many people will initially have compensatory increases in second-phase insulin secretion.  By delaying glucose absorption, these medications match the timing of incoming glucose to the insulin secretory patterns.

Medications that increase insulin secretion

Classes: sulfonylureas, meglitinides, D-phenylalanine derivatives

Efficacy with respect to insulin resistance: Any medication that reduces glucose levels decreases glucose toxicity and thus decreases insulin resistance. They probably have little direct effect on insulin resistance, but their use often results in improvements in insulin sensitivity because of reductions in glucose concentrations which reduce glucose toxicity.

Efficacy with respect to insulin level: Medications that increase insulin secretion exert their effect on:

 DCMS185CG1

PLEASE NOTE: Since the publication of this text, there have been two additions to the above list; the SLGT-2 inhibitor class of drugs (More info at our SGLT2 Inhibitor topic resource center: SGLT2 Inhibitors.) and the Centrally Acting Dopamine Agonists class which includes Cycloset/Bromocriptine Mesylate — more info in our article here.

Next Excerpt: Medications that Improve Insulin Action

Copyright © 2010 by Joslin Diabetes Center. All rights reserved. Reprinted with permission. Neither this book nor any part thereof may be reproduced or distributed in any form or by any means without permission in writing from Joslin. Note: Joslin does not endorse products or services.

You can purchase the updated 2nd Edition of JOSLIN’S DIABETES DESKBOOK at:

https://www.joslin.org/jstore/books_for_healthcare_professionals.html

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.

Professionals must use their own professional medical judgment, training and experience and should not rely solely on the information provided in this book to make recommendations to patients with regard to nutrition or exercise or to prescribe medications.

This book is not intended to encourage the treatment of illness, disease or any other medical problem by the layperson. Any application of the recommendations set forth in the following pages is at the reader’s discretion and sole risk. Laypersons are strongly advised to consult a physician or other healthcare professional before altering or undertaking any exercise or nutritional program or before taking any medication referred to in this book.