PH7.1 | PH7.1 | Diabetes Mellitus Pharmacotherapy — SDL Guide — Summary & Reflection

KEY TAKEAWAYS

Diabetes Mellitus Pharmacotherapy — Key Takeaways:

• Insulin types: rapid-acting analogues (lispro/aspart/glulisine) → onset 5–15 min; short-acting regular → onset 30–60 min; NPH (intermediate) → peak 6–10 hr; long-acting analogues (glargine/detemir/degludec) → near-peakless, 20–42 hr.
• Sulfonylurea generations: 1st-gen = tolbutamide, chlorpropamide; 2nd-gen = glibenclamide, glipizide, gliclazide (Indian favourite), glimepiride. Glimepiride is 2nd-gen, NOT 3rd-gen.
• Tirzepatide = dual GIP/GLP-1 agonist (NOT a selective GLP-1 RA). Semaglutide/liraglutide = selective GLP-1 RAs.
• SGLT2i eGFR rule: glycaemic benefit threshold ~eGFR 45; cardio-renal benefit continues to ~eGFR 20 (drug-specific).
• Avoid pioglitazone in HF (worsens fluid retention); stop metformin when eGFR <30.
• Obese T2DM: prefer GLP-1 RA, SGLT2i, DPP-4i (weight-neutral/reducing). Avoid SU, TZDs, insulin if alternatives exist.
• CV/renal comorbidity drives drug choice beyond glucose: EMPA-REG (MACE/CV death), DECLARE (HHF↓), LEADER (MACE↓), CREDENCE (CKD), DAPA-CKD (CKD incl. non-diabetics).
• Combination logic: no redundant mechanisms (e.g. SU + meglitinide both close KATP — irrational combination); prefer complementary mechanisms.

REFLECT

Think about a diabetic patient you have seen (or imagine one based on this guide). They are on glibenclamide and metformin but their HbA1c is 9.5% after 2 years. Now they have developed HFrEF on ECHO. What changes would you make to their regimen? Which drug would you add, which would you consider stopping, and how would the eGFR value at that visit change your answer? Write three bullet points: (1) what you would change, (2) the mechanistic reason, (3) what monitoring you would plan for the next 3 months. Reflect on how understanding drug mechanisms — not just drug names — enables safe, evidence-based prescribing.