What are the brand and generic names, dosage forms, pharmacologic categories, FDA-approved indications, dosages, mechanisms of action, contraindications, adverse effects, drug interactions, and patient counseling points for medications such as Metformin (Glucophage), Sitagliptin (Januvia), Empagliflozin (Jardiance), Atorvastatin (Lipitor), Amlodipine, and Enalapril, among others?

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Last updated: August 22, 2025 • View editorial policy

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Comprehensive Guide to Diabetes and Cardiovascular Medications

Brand and Generic Names, Dosage Forms, and Pharmacologic Categories

Metformin (Glucophage) is the first-line medication for type 2 diabetes due to its effectiveness, safety, low cost, and potential to reduce cardiovascular events and death. 1

Biguanides

  • Metformin (Glucophage)
    • Dosage forms: Immediate-release (IR) tablets (500mg, 850mg, 1000mg); Extended-release (ER) tablets (500mg, 750mg, 1000mg)
    • Maximum daily dose: 2000-2550mg
    • Mechanism: Decreases hepatic glucose production, improves insulin sensitivity
    • Cost: Most affordable option ($2-4 for generic IR formulations)

DPP-4 Inhibitors

  • Sitagliptin (Januvia)
    • Dosage form: Tablets (25mg, 50mg, 100mg)
    • Maximum daily dose: 100mg once daily
    • Mechanism: Increases insulin secretion and reduces glucagon in glucose-dependent manner
    • Cost: $477 per month (100mg)
  • Saxagliptin (Onglyza), Linagliptin (Tradjenta), Alogliptin
    • Similar mechanism with varying costs ($166-466 per month)

SGLT2 Inhibitors

  • Empagliflozin (Jardiance)
    • Dosage form: Tablets (10mg, 25mg)
    • Maximum daily dose: 25mg once daily
    • Mechanism: Blocks glucose reabsorption in proximal renal tubule
    • Cost: $526 per month (25mg)
    • Notable benefit: Reduces cardiovascular mortality by 38% and all-cause mortality by 32% in patients with established cardiovascular disease 2
  • Dapagliflozin (Farxiga), Canagliflozin (Invokana), Ertugliflozin
    • Similar mechanism with comparable costs ($257-521 per month)

GLP-1 Receptor Agonists

  • Semaglutide (Ozempic/Rybelsus/Wegovy)
    • Dosage forms: Subcutaneous injection (0.25mg, 0.5mg, 1mg); Oral tablets (3mg, 7mg, 14mg)
    • Maximum dose: 1mg weekly (injection) or 14mg daily (oral)
    • Mechanism: Stimulates insulin secretion, reduces glucagon, improves satiety
    • Cost: $779-822 per month
  • Dulaglutide (Trulicity), Liraglutide (Victoza/Saxenda), Exenatide (Byetta/Bydureon)
    • Similar mechanisms with varying costs ($634-975 per month)

Statins

  • Atorvastatin (Lipitor)
    • Dosage form: Tablets (10mg, 20mg, 40mg, 80mg)
    • Mechanism: HMG-CoA reductase inhibitor, reduces cholesterol production
  • Rosuvastatin (Crestor), Simvastatin (Zocor), Pravastatin (Pravachol), Lovastatin (Mevacor)
    • Similar mechanism with varying potency and side effect profiles

FDA-Approved Indications

Antidiabetic Medications

  • Metformin: First-line therapy for type 2 diabetes
  • SGLT2 Inhibitors: Type 2 diabetes; some (empagliflozin, canagliflozin, dapagliflozin) are also approved for heart failure and chronic kidney disease
  • DPP-4 Inhibitors: Type 2 diabetes
  • GLP-1 RAs: Type 2 diabetes; some are also approved for weight management

Cardiovascular Medications

  • Statins: Primary and secondary prevention of cardiovascular disease, hyperlipidemia
  • ACE Inhibitors (Enalapril/Vasotec): Hypertension, heart failure, post-myocardial infarction, diabetic nephropathy

Contraindications

Metformin

  • eGFR <30 mL/min/1.73m²
  • Acute or unstable heart failure
  • Radiographic studies using iodinated contrast (temporary hold)
  • Acute kidney injury, hepatic impairment, alcoholism

SGLT2 Inhibitors

  • Type 1 diabetes
  • eGFR <30 mL/min/1.73m² (varies by agent)
  • Dialysis patients
  • History of diabetic ketoacidosis

DPP-4 Inhibitors

  • History of serious hypersensitivity to the medication
  • Caution with history of pancreatitis

Thiazolidinediones

  • Symptomatic heart failure (Class III-IV) 1
  • Active liver disease or ALT >2.5 times upper limit of normal

Adverse Effects

Metformin

  • Gastrointestinal: Bloating, abdominal discomfort, diarrhea
  • Rare: Lactic acidosis (very rare with normal renal function)
  • Vitamin B12 deficiency with long-term use

SGLT2 Inhibitors

  • Genital mycotic infections
  • Urinary tract infections
  • Volume depletion/hypotension
  • Euglycemic diabetic ketoacidosis
  • Increased risk of lower limb amputations (canagliflozin)
  • Bone fractures (canagliflozin)

DPP-4 Inhibitors

  • Generally well tolerated
  • Rare: Pancreatitis, joint pain
  • Potential increased risk of heart failure hospitalization (saxagliptin)

GLP-1 RAs

  • Gastrointestinal: Nausea, vomiting, diarrhea
  • Injection site reactions
  • Rare: Pancreatitis, thyroid C-cell tumors (contraindicated with personal/family history of MTC)

Drug Interactions

Metformin

  • Cationic drugs (cimetidine, digoxin) may increase levels
  • Alcohol increases risk of lactic acidosis
  • Temporary hold for iodinated contrast studies

SGLT2 Inhibitors

  • Loop diuretics: Increased risk of volume depletion
  • Insulin/sulfonylureas: Increased risk of hypoglycemia
  • NSAIDs: Potential increased risk of acute kidney injury

DPP-4 Inhibitors

  • Minimal drug interactions
  • May increase digoxin levels

Statins

  • CYP3A4 inhibitors (clarithromycin, itraconazole): Increased statin levels
  • Gemfibrozil: Increased risk of myopathy/rhabdomyolysis
  • Grapefruit juice: Increased levels of atorvastatin, simvastatin

Patient Counseling Points

Metformin

  • Take with meals to minimize GI side effects
  • Start at low dose and titrate slowly
  • Monitor kidney function regularly
  • Watch for vitamin B12 deficiency with long-term use

SGLT2 Inhibitors

  • Expect increased urination
  • Maintain adequate hydration
  • Practice good genital hygiene
  • Report symptoms of genital infections promptly
  • Seek immediate medical attention for severe abdominal pain, vomiting, or shortness of breath (potential DKA)

DPP-4 Inhibitors

  • Can be taken with or without food
  • Report persistent severe abdominal pain (potential pancreatitis)
  • Low risk of hypoglycemia when used as monotherapy

GLP-1 RAs

  • Inject subcutaneously as directed (thigh, abdomen, upper arm)
  • Rotate injection sites
  • Store as directed (refrigeration for unopened pens)
  • Start at low dose and titrate to minimize GI side effects
  • Report persistent severe abdominal pain

Treatment Selection Algorithm

  1. First-line therapy: Metformin (unless contraindicated) 1

    • Start with low dose (500mg once or twice daily)
    • Titrate gradually to minimize GI side effects
    • Target dose: 1000mg twice daily or 2000mg ER once daily

  2. Second-line therapy (if A1C target not achieved after 3 months):

    • For patients with established ASCVD, heart failure, or CKD: Add SGLT2 inhibitor with proven cardiovascular benefit (empagliflozin, canagliflozin, dapagliflozin) 1
    • For patients needing greater weight loss: Add GLP-1 RA (semaglutide preferred for efficacy) 1
    • For patients with cost concerns or minimal comorbidities: Consider sulfonylurea (glimepiride preferred for lower hypoglycemia risk) 1

  3. Third-line therapy (if A1C target not achieved after 3 months of dual therapy):

    • Add agent from another class based on patient characteristics
    • Consider combination injectable therapy if A1C remains significantly elevated

Comparative Efficacy

  • A1C reduction:

    • Metformin: 1.0-1.5%
    • SGLT2 inhibitors: 0.7-1.0%
    • DPP-4 inhibitors: 0.5-0.8%
    • GLP-1 RAs: 1.0-1.8% (semaglutide highest)
    • Sulfonylureas: 1.0-1.5%

  • Cardiovascular outcomes:

    • SGLT2 inhibitors and GLP-1 RAs have demonstrated cardiovascular benefits
    • Empagliflozin reduces cardiovascular death by 38% in patients with established CVD 2
    • DPP-4 inhibitors are generally neutral for cardiovascular outcomes
    • Sulfonylureas have mixed data regarding cardiovascular safety

  • Weight effects:

    • Weight loss: GLP-1 RAs (2-6 kg) > SGLT2 inhibitors (2-3 kg) > Metformin (neutral to modest loss)
    • Weight neutral: DPP-4 inhibitors
    • Weight gain: Sulfonylureas, Thiazolidinediones, Insulin

Special Considerations

  • Renal impairment: Linagliptin requires no dose adjustment in renal insufficiency 2
  • Heart failure: SGLT2 inhibitors beneficial; avoid thiazolidinediones 1
  • Elderly patients: Start with lower doses; monitor for volume depletion with SGLT2 inhibitors
  • Hypoglycemia risk: Highest with insulin and sulfonylureas; minimal with metformin, SGLT2 inhibitors, DPP-4 inhibitors, and GLP-1 RAs when used as monotherapy

References

1
Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

2
Guideline

Type 2 Diabetes Management

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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