Different T2DM Medications and Target Sites

1. Pancreas

• Sulfonylureas (e.g., glipizide, glyburide): Block ATP-sensitive K+ channels on beta cells → depolarization → Ca²+ influx → insulin release. Risk of hypoglycemia and weight gain.
• Glinides/Meglitinides (e.g., repaglinide): Same mechanism as sulfonylureas but faster onset and shorter duration - best for postprandial glucose spikes.
• GLP-1 Receptor Agonists (GLP-1 RA) (e.g., semaglutide, liraglutide): Mimic the incretin hormone GLP-1, stimulating glucose-dependent insulin secretion (only when glucose is elevated, so lower hypoglycemia risk).
• DPP-4 Inhibitors (e.g., sitagliptin): Block the enzyme DPP-4, which normally breaks down GLP-1 and GIP, thereby prolonging incretin action and boosting insulin release.

2. Brain

• GLP-1 RA: Act centrally to reduce appetite and food intake, contributing to weight loss and indirectly improving glucose control.
• Bromocriptine (a dopamine agonist): Acts in the hypothalamus to reset circadian rhythms of dopamine release, which reduces insulin resistance. Its exact glucose-lowering mechanism is not fully understood.

3. Gut (Intestine)

• Alpha-glucosidase Inhibitors (e.g., acarbose): Block intestinal enzymes that break down complex carbohydrates, slowing glucose absorption after meals.
• GLP-1 RA: Also slow gastric emptying, reducing the rate of glucose entry into the bloodstream.
• Colesevelam (a bile acid sequestrant): Primarily a cholesterol-lowering drug that also modestly lowers blood glucose by an unclear mechanism - likely involves altered bile acid signaling in the gut.
• Metformin: Increases GLP-1 secretion from gut L-cells and may alter bile acid reabsorption as part of its multi-organ mechanism.

4. Liver

• Metformin: Activates AMPK in the liver → suppresses gluconeogenesis (glucose production from scratch) and glycogenolysis (breakdown of glycogen to glucose). This is its primary mechanism - it reduces fasting blood glucose by cutting off excess hepatic glucose output.
• TZDs (e.g., pioglitazone): Activate PPARγ receptors in the liver, increasing insulin sensitivity and reducing hepatic glucose output.

5. Kidney

• SGLT2 Inhibitors (e.g., empagliflozin, dapagliflozin): Block sodium-glucose cotransporter-2 (SGLT2) in the proximal tubule of the kidney, preventing glucose reabsorption. Excess glucose is excreted in the urine (glucosuria). Bonus benefits include reduced blood pressure, weight loss, and cardio/renal protection.

6. Muscle

• TZDs: Activate PPARγ in skeletal muscle, upregulating genes involved in insulin-stimulated glucose uptake (e.g., GLUT4 transporters). This reduces peripheral insulin resistance.

7. Adipose Tissue

• TZDs: Their primary site of PPARγ activation is actually fat tissue, where they promote differentiation of new, more insulin-sensitive adipocytes. This redistributes fat from visceral to subcutaneous depots, which is metabolically favorable - though it can cause weight gain overall.

Summary Table

Presentation Script: T2DM Medications and Their Target Sites

Slide 1 - Introduction (Opening)

"Good [morning/afternoon], today I will be presenting the different medications used to treat Type 2 Diabetes Mellitus, and the specific organs they target in the body."

"Type 2 diabetes is characterized by insulin resistance and eventually impaired insulin secretion, leading to chronically high blood glucose - called hyperglycemia. Because diabetes affects multiple organs, we have a wide range of drugs that each work at a different site to bring blood sugar down."

Slide 2 - The Big Picture

"This diagram shows seven target organs, each with one or more drug classes acting on it. All of these drugs ultimately reduce hyperglycemia, but they do so through completely different mechanisms. This is why combination therapy is so powerful in T2DM - you can attack the problem from multiple angles at once."

Slide 3 - The Pancreas (Insulin Secretagogues)

"Starting with the pancreas. Four drug classes work here, and their job is to make the beta cells release more insulin."

• "Sulfonylureas block potassium channels on beta cells, causing depolarization, calcium influx, and insulin release. The downside is hypoglycemia and weight gain."
• "Glinides work the same way but act faster and wear off sooner - they're ideal for controlling blood sugar spikes after meals."
• "GLP-1 Receptor Agonists, like semaglutide, mimic a natural gut hormone that tells the pancreas to release insulin only when glucose is high - so the hypoglycemia risk is much lower."
• "DPP-4 Inhibitors prevent the breakdown of that same natural hormone, prolonging its effect."

Slide 4 - The Liver and Peripheral Tissues (Insulin Sensitizers)

"Moving to the liver. The biggest problem in T2DM is that the liver keeps producing glucose even when blood sugar is already high. Two drugs fix this:"

• "Metformin, the first-line drug for T2DM, activates an enzyme called AMPK in the liver, which shuts down excess glucose production. It also improves insulin sensitivity in muscle."
• "TZDs - Thiazolidinediones - like pioglitazone, activate PPARγ receptors in the liver, muscle, AND fat tissue, making all three tissues more responsive to insulin. They are insulin sensitizers, not secretagogues."

Slide 5 - The Kidney, Gut, and Brain

"Finally, three more target sites:"

• "The kidney: SGLT2 inhibitors block glucose reabsorption in the kidney, so excess glucose is literally excreted in the urine. These drugs also have proven heart and kidney protective benefits."
• "The gut: Alpha-glucosidase inhibitors slow down carbohydrate digestion, so glucose enters the blood more slowly after meals. Colesevelam, a bile acid binder, also has a modest glucose-lowering effect through gut signaling."
• "The brain: GLP-1 RAs act centrally to reduce appetite and food intake. Bromocriptine, a dopamine agonist, resets the brain's circadian control of metabolism - though its exact mechanism is not fully understood."

Slide 6 - Summary & Conclusion (Closing)

"To summarize:"

Organ	Drug Class
Pancreas	Sulfonylureas, Glinides, GLP-1 RA, DPP-4 inhibitors
Liver	Metformin, TZDs
Muscle & Fat	TZDs
Kidney	SGLT2 inhibitors
Gut	Alpha-glucosidase inhibitors, Colesevelam
Brain	GLP-1 RA, Bromocriptine

"The key takeaway is that no single drug solves all aspects of T2DM. That is why we combine drugs from different classes - to address insulin deficiency, insulin resistance, excess hepatic glucose, and slow absorption all at the same time."

"Thank you. I am happy to take any questions."

Tips for delivery:

• Point to each organ on the diagram as you mention it
• Emphasize that all arrows point toward "decreased hyperglycemia" - the drugs work through different paths but share the same goal
• If your teacher asks "why not just use one drug?" - your answer is: because the disease has multiple defects happening at once

Class Presentation Script

"Management of Diabetes Mellitus - Pharmacological Approach"

Opening (Slide 1)

"Good [morning/afternoon] everyone. Today I'm going to walk you through the pharmacological - meaning drug-based - management of Type 2 Diabetes Mellitus, or T2DM.

There are 6 main drug classes we'll cover. For each one, I'll tell you: what it is, how it works, when we use it, and what side effects to watch for. Let's go."

Drug 1: METFORMIN (Slide 2)

"Metformin is the first drug almost every T2DM patient gets. Think of it as the foundation of diabetes treatment.

How it works: It goes to the liver and tells it to stop producing so much glucose. It also makes cells more sensitive to insulin.*

Dose: We start low - 500 mg once daily with dinner - and increase slowly every 1-2 weeks to reduce stomach upset. The usual maintenance dose is 1,500-2,000 mg per day.*

Side effects to remember: Nausea, vomiting, diarrhea, metallic taste, and with long-term use it can cause Vitamin B12 deficiency.*

Important contraindication: Do NOT give it if the patient's kidney function is poor - specifically eGFR below 30 - because it can cause a dangerous buildup called lactic acidosis."*

Drug 2: SULFONYLUREAS (Slide 3)

"When metformin alone isn't enough, we often add a Sulfonylurea. The main ones are Glimepiride, Glipizide, and Glyburide.

How they work: They squeeze the pancreas to release more insulin. Simple as that. They bind to channels on beta cells and trigger insulin secretion.*

Key doses to know:

• Glimepiride: Start at 1 mg/day, max 8 mg/day
• Glipizide: Start at 5 mg/day, max 40 mg/day
• Glyburide: Start at 2.5-5 mg/day, max 20 mg/day

The two big side effects: Hypoglycemia - because they force insulin out even when sugar is normal - and weight gain.*

Tip for class: These are the ONLY oral drugs that commonly cause hypoglycemia as a major problem."*

Drug 3: SGLT2 INHIBITORS (Slide 4)

"SGLT2 inhibitors are one of the most exciting newer drug classes. Think of them as making the kidney 'pee out' extra glucose.

How they work: The kidney normally reabsorbs all filtered glucose back into the blood. SGLT2 inhibitors BLOCK that reabsorption, so glucose gets excreted in the urine instead.*

The four drugs:

• Empagliflozin (most preferred by ADA 2026): 10-25 mg/day
• Dapagliflozin: 5-10 mg/day
• Canagliflozin: 100-300 mg/day
• Ertugliflozin: 5-15 mg/day

Bonus benefits beyond glucose: They protect the heart in heart failure, protect the kidneys in CKD, and help with weight loss.*

Side effects: Genital fungal infections and UTIs - because glucose in the urine feeds bacteria and fungi.*

Don't give if: eGFR is below 30-45, or the patient has Type 1 diabetes (risk of DKA)."*

Drug 4: GLP-1 RECEPTOR AGONISTS (Slide 5)

"GLP-1 RAs are the other exciting newer class - and you've probably heard of Semaglutide (Ozempic) in the news.

How they work: They mimic GLP-1, a natural gut hormone that:

• Tells the pancreas to release insulin ONLY when glucose is high
• Slows down stomach emptying so glucose rises slowly after meals
• Acts in the brain to reduce appetite*

Key drugs and doses:

• Semaglutide (injectable): Start 0.25 mg weekly, go up to 2 mg weekly
• Oral Semaglutide (Rybelsus): Start 3 mg → 7 mg → 14 mg daily
• Dulaglutide: 0.75 mg weekly, up to 4.5 mg weekly
• Liraglutide: 0.6 mg → 1.2 mg → 1.8 mg daily

ADA 2026 recommends GLP-1 RAs especially for patients with:

• Heart disease (ASCVD)
• CKD
• Obesity/weight management needs

Side effects: Nausea, vomiting, diarrhea - mainly GI. Usually improve over time.*

Contraindication: Personal or family history of medullary thyroid cancer or MEN2 syndrome."*

Drug 5: DPP-4 INHIBITORS (Slide 6)

"DPP-4 inhibitors are sometimes called the 'gentle' diabetes drugs. They are weight-neutral and have low hypoglycemia risk.

How they work: There's an enzyme called DPP-4 that breaks down your natural GLP-1 hormone. These drugs BLOCK that enzyme, so your own GLP-1 lasts longer and keeps stimulating insulin release.*

The four drugs:

• Sitagliptin: 100 mg/day (reduce dose in kidney disease)
• Saxagliptin: 5 mg/day
• Linagliptin: 5 mg/day (unique - NO dose adjustment needed in kidney disease)
• Alogliptin: 25 mg/day

Side effects: Mostly mild - runny nose, headache, mild stomach upset. Rarely, joint pain.*

Important rule: Do NOT combine with GLP-1 RAs or tirzepatide - they work on the same pathway, so combining them adds no benefit and increases side effects."*

Drug 6: THIAZOLIDINEDIONES - TZDs (Slide 7)

"TZDs - the main one being Pioglitazone - are insulin sensitizers.

How they work: They activate a nuclear receptor called PPARγ inside fat, liver, and muscle cells. This turns on genes that make those cells respond better to insulin. They don't make more insulin - they make existing insulin work better.*

Dose: Start at 15-30 mg once daily, increase every 4-12 weeks up to 45 mg/day.*

*ADA 2026 also recommends TZDs for patients with liver disease called MASH/MASLD - fatty liver with inflammation.

Side effects: Weight gain, fluid retention/swelling, increased fracture risk in women.*

Absolute contraindication: Heart failure (NYHA Class III/IV) - because the fluid retention makes heart failure worse."*

Drug 7: INSULIN (Slide 8)

"Finally, when all else fails, or in severe cases from the start, we use insulin.

Types of insulin:

• Rapid-acting (Lispro, Aspart): Works in 15 min, used with meals
• Short-acting (Regular): Used before meals or in hospital
• Intermediate-acting (NPH): Covers part of the day
• Long-acting/Basal (Glargine, Detemir): Once daily background insulin
• Ultra-long-acting (Degludec, Glargine U-300): Lasts over 24 hours
• Premixed: Combinations for convenience

Starting dose in T2DM: 10 units/day OR 0.1-0.2 units/kg/day of basal insulin. Increase by 2 units every 3 days until fasting glucose is at target.*

Mandatory in: Type 1 diabetes, DKA, HHS, pregnancy with diabetes, and T2DM patients who fail all other drugs.*

Main side effects: Hypoglycemia and weight gain."*

Closing Summary (Slide 9)

"So to wrap up - here's how to remember the 6+1 drug classes:"

"In real clinical practice, we combine these drugs based on the patient's other conditions - heart failure, kidney disease, obesity - not just their blood sugar. That is what makes modern diabetes management so personalized. Thank you!"

Quick Presentation Tips:

• Spend most time on Metformin, SGLT2 inhibitors, and GLP-1 RAs - these are the most clinically tested and exam-relevant
• For each drug, always follow this order: What it does → How it works → Dose → Side effects → When NOT to use it
• If your class asks "which is best?" - the honest answer is: it depends on the patient's other medical conditions

Page 9 Explained: Insulin Types - Onset, Peak & Duration

The Big Concept First

"Not all insulins are the same. Some act fast for meals, some act slowly as background coverage. To treat diabetes properly, you need to match the RIGHT insulin to the RIGHT time of day."

The 6 Types of Insulin (in order from fastest to slowest)

Brand Names to Know

How to Explain This in Class - Simple Analogy

"Think of insulin like workers covering a shift:"

• Rapid-acting = a fast sprinter - works immediately for your meal right now
• Short-acting = a regular worker - needs 30 min to get ready before the meal
• Intermediate-acting = a mid-shift worker - covers the afternoon, has a hump
• Long-acting = the overnight security guard - slow, steady, no peak, covers 24 hours
• Pre-mixed = a combo pack - one injection covers both the meal AND the background

Key Point for the Exam

"The most important concept is: long-acting insulin has NO peak. This is why it causes less hypoglycemia - it gives a flat, steady baseline instead of a sudden spike and drop. Lantus (glargine) and Levemir (detemir) are the most commonly used basal insulins."

Why This Table Matters Clinically

• A patient with T2DM who is newly starting insulin usually gets just basal (long-acting) insulin once at night
• A patient with T1DM needs basal + rapid-acting (called a basal-bolus regimen) - long-acting for background, rapid-acting for every meal
• Pre-mixed insulins are a convenient shortcut for patients who don't want to inject multiple times

Verification: Your PDF has 10 slides, all correct

Important - I Missed Slide 1 Earlier

Flowchart: "Use of Glucose-Lowering Medications in T2DM"

• Healthy lifestyle, diabetes self-management education, address social determinants of health
• Goal: achieve and maintain weight + glycemic targets

• Add agents based on the individual patient's metabolic comorbidities, need for weight loss, hypoglycemia risk, and barriers to care

How to present the flowchart to your class:

"The ADA 2026 flowchart tells us: don't just pick a drug based on blood sugar alone. First ask - does this patient have heart disease? Kidney disease? Fatty liver? Each condition has a preferred drug that gives extra organ protection beyond just lowering glucose. Only AFTER addressing those do we fine-tune for glycemic control alone."