Medical Pharmacology: Chapter 29 — Diabetes Pharmacology -- Module 7 — Special Clinical Contexts in Diabetes Pharmacology

Chapter 29 — Diabetes Pharmacology — Module 7 — Special Clinical Contexts in Diabetes Pharmacology

1. [CASE 1 — QUESTION 1] A 62-year-old man with type 2 diabetes mellitus (T2DM) of 9 years is seen in clinic 8 weeks after a non-fatal anterior myocardial infarction treated with percutaneous coronary intervention. He takes metformin 1000 mg twice daily, high-intensity atorvastatin, aspirin, a P2Y12 inhibitor, a beta-blocker, and an angiotensin-converting enzyme (ACE) inhibitor. His HbA1c is 7.8%, estimated glomerular filtration rate (eGFR) is 74 mL per minute per 1.73 m squared, and he has no symptoms or signs of heart failure. The team wants to add an agent that reduces his risk of a recurrent atherosclerotic event. Which add-on is best supported for this goal?

A) Glipizide, to lower HbA1c and thereby reduce atherosclerotic events
B) Saxagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, for cardiovascular event reduction
C) A glucagon-like peptide-1 receptor (GLP-1R) agonist such as liraglutide or subcutaneous semaglutide, which reduced major adverse cardiovascular events including non-fatal myocardial infarction and stroke in cardiovascular outcome trials
D) Pioglitazone, for peroxisome proliferator-activated receptor-gamma (PPAR-gamma) mediated atherosclerotic protection
E) Acarbose, to blunt postprandial hyperglycemia and reduce cardiovascular risk

ANSWER: C

Rationale:

In a patient with established atherosclerotic cardiovascular disease whose immediate priority is reducing recurrent atherosclerotic events, a GLP-1R agonist such as liraglutide or subcutaneous semaglutide is preferred because this class reduced major adverse cardiovascular events, including non-fatal myocardial infarction and stroke, in cardiovascular outcome trials such as LEADER and SUSTAIN-6.

Option A: Option A is incorrect because sulfonylurea-mediated glycemic lowering does not reduce atherosclerotic events and adds hypoglycemia risk.
Option B: Option B is incorrect because DPP-4 inhibitors are cardiovascular-neutral and saxagliptin additionally increases heart failure hospitalization.
Option D: Option D is incorrect because pioglitazone is not used for atherosclerotic event reduction and causes fluid retention.
Option E: Option E is incorrect because acarbose has no established atherosclerotic outcome benefit in this setting.

2. [CASE 1 — QUESTION 2] Continuing with the same patient. Eighteen months later he is started on a GLP-1R agonist and his atherosclerotic disease remains stable, but he is now hospitalized for new heart failure with a left ventricular ejection fraction of 34%. His eGFR is 66 mL per minute per 1.73 m squared. The team wants to add an agent that directly reduces cardiovascular death and heart failure hospitalization. Which addition best meets this goal?

A) An SGLT-2 inhibitor such as empagliflozin or dapagliflozin, which reduces cardiovascular death and heart failure hospitalization across the ejection fraction spectrum
B) Pioglitazone, to improve insulin sensitivity and support the failing heart
C) Saxagliptin, for its favorable heart failure profile
D) A long-acting sulfonylurea, to tighten glycemic control and offload the heart
E) Replace the GLP-1R agonist with a second DPP-4 inhibitor

ANSWER: A

Rationale:

With new heart failure with reduced ejection fraction, an SGLT-2 inhibitor such as empagliflozin or dapagliflozin is the best addition because the class reduces cardiovascular death and heart failure hospitalization, complementing the atherosclerotic benefit of his existing GLP-1R agonist.

Option B: Option B is incorrect because pioglitazone causes sodium and water retention and is contraindicated in this degree of heart failure.
Option C: Option C is incorrect because saxagliptin increases heart failure hospitalization.
Option D: Option D is incorrect because sulfonylureas do not improve heart failure outcomes and add hypoglycemia risk.
Option E: Option E is incorrect because removing the GLP-1R agonist would forfeit atherosclerotic protection and a DPP-4 inhibitor does not address heart failure.

3. [CASE 1 — QUESTION 3] Continuing with the same patient. A covering physician, unaware of his ejection fraction of 34%, considers four options to further improve glycemic control. Which proposed agent is specifically contraindicated given his New York Heart Association (NYHA) class III heart failure with reduced ejection fraction?

A) Linagliptin, a DPP-4 inhibitor with neutral heart failure outcomes
B) Pioglitazone, a thiazolidinedione that promotes sodium and water retention through PPAR-gamma activation and is contraindicated in NYHA class III or IV heart failure
C) An additional SGLT-2 inhibitor dose adjustment
D) Continuation of metformin at his current renal function
E) Insulin titration with hypoglycemia monitoring

ANSWER: B

Rationale:

Pioglitazone is a thiazolidinedione that promotes sodium and water retention through PPAR-gamma activation in the collecting duct and is contraindicated in NYHA class III or IV heart failure, making it the dangerous choice in this patient with an ejection fraction of 34%.

Option A: Option A is incorrect because linagliptin has neutral heart failure outcomes and is not contraindicated.
Option C: Option C is incorrect because an SGLT-2 inhibitor benefits heart failure with reduced ejection fraction.
Option D: Option D is incorrect because metformin is acceptable at his preserved renal function and is not contraindicated in heart failure per se.
Option E: Option E is incorrect because insulin can be used with appropriate monitoring and is not contraindicated.

4. [CASE 1 — QUESTION 4] Continuing with the same patient. He is now 64 years old with established cardiovascular disease and heart failure, on metformin, a GLP-1R agonist, and an SGLT-2 inhibitor. His current HbA1c is 7.6%. He asks what HbA1c goal is appropriate for him. Which target and rationale are most appropriate?

A) Below 6.0%, because the tightest possible control maximizes cardiovascular benefit in all patients
B) Below 6.5% achieved with the addition of a long-acting sulfonylurea
C) Any value is acceptable; glycemic target is irrelevant once cardiovascular agents are in place
D) A less stringent HbA1c of approximately 7.5 to 8.0%, individualized because his established cardiovascular disease and comorbidities raise the harm of hypoglycemia relative to the marginal benefit of tighter control
E) Below 7.0% achieved primarily by escalating insulin regardless of hypoglycemia risk

ANSWER: D

Rationale:

In a patient with established cardiovascular disease and comorbidities, a less stringent individualized HbA1c target of roughly 7.5 to 8.0% is appropriate because the harm of hypoglycemia outweighs the marginal benefit of tighter control, and his cardiovascular protection now derives chiefly from his GLP-1R agonist and SGLT-2 inhibitor rather than from intensive glucose lowering.

Option A: Option A is incorrect because a sub-6.0% target increases hypoglycemia risk without added cardiovascular benefit.
Option B: Option B is incorrect because a sulfonylurea adds hypoglycemia risk to reach an overly tight target.
Option C: Option C is incorrect because a reasonable glycemic target still matters for symptoms and microvascular risk.
Option E: Option E is incorrect because aggressive insulin escalation ignoring hypoglycemia risk is inappropriate in this population.

5. [CASE 2 — QUESTION 1] A 58-year-old woman with T2DM of 12 years has diabetic kidney disease. Her eGFR is 46 mL per minute per 1.73 m squared and her urinary albumin-to-creatinine ratio (UACR) is 540 mg per gram despite a maximally tolerated ACE inhibitor. She has no heart failure. She takes metformin and the ACE inhibitor. The nephrology team wants to slow her kidney disease progression. Which addition is best supported?

A) Increase the ACE inhibitor above its maximum tolerated dose
B) Add a DPP-4 inhibitor for disease-modifying renal protection
C) Add a sulfonylurea, since improved glycemic control alone will halt nephropathy
D) Stop the ACE inhibitor and rely on glycemic control
E) Add an SGLT-2 inhibitor, which provided additive renal protection on a background of maximally tolerated renin-angiotensin-aldosterone system (RAAS) blockade in patients with this degree of albuminuria, through afferent arteriolar pressure reduction

ANSWER: E

Rationale:

Adding an SGLT-2 inhibitor is best supported because it provides additive renal protection on a background of maximally tolerated RAAS blockade through afferent arteriolar pressure reduction, as demonstrated in the CREDENCE trial in patients with this degree of albuminuria and eGFR.

Option A: Option A is incorrect because escalating the ACE inhibitor beyond maximum tolerated dose is not recommended and risks hyperkalemia and hypotension.
Option B: Option B is incorrect because DPP-4 inhibitors are not disease-modifying for kidney disease.
Option C: Option C is incorrect because glycemic control alone with a sulfonylurea does not provide disease-modifying nephroprotection and adds hypoglycemia risk.
Option D: Option D is incorrect because stopping RAAS blockade removes an established nephroprotective therapy.

6. [CASE 2 — QUESTION 2] Continuing with the same patient. Two years later her eGFR has declined to 28 mL per minute per 1.73 m squared. Her current regimen is metformin, the ACE inhibitor, an SGLT-2 inhibitor, and glibenclamide (glyburide) that was added elsewhere. She reports episodes of sweating and tremor before lunch. Which medication reconciliation is correct at this eGFR?

A) Continue all agents unchanged
B) Stop the SGLT-2 inhibitor and continue metformin and glibenclamide
C) Stop metformin (eGFR now below 30) and stop glibenclamide (accumulating active renally cleared metabolites are the likely cause of her hypoglycemia), while continuing the SGLT-2 inhibitor for its renal benefit as long as it remains within its eGFR floor
D) Increase glibenclamide to control fasting glucose
E) Stop the ACE inhibitor to protect renal function

ANSWER: C

Rationale:

At an eGFR of 28, metformin should be stopped because it has fallen below the continuation threshold of 30, and glibenclamide should be stopped because its active renally cleared metabolites accumulate and are the likely cause of her premeal hypoglycemia; the SGLT-2 inhibitor can continue for renal benefit as long as it remains within its indication-specific eGFR floor.

Option A: Option A is incorrect because both metformin and glibenclamide are now unsafe.
Option B: Option B is incorrect because it stops the beneficial SGLT-2 inhibitor while continuing the two unsafe agents.
Option D: Option D is incorrect because increasing glibenclamide worsens the hypoglycemia.
Option E: Option E is incorrect because the ACE inhibitor is nephroprotective and is not the agent that should be stopped here.

7. [CASE 2 — QUESTION 3] Continuing with the same patient. After stopping metformin and glibenclamide, she is started on basal insulin. As her eGFR continues to decline toward 18 mL per minute per 1.73 m squared, the team anticipates a change in her insulin requirement. Which statement correctly describes the expected change and its basis?

A) Insulin requirements tend to fall in advanced chronic kidney disease because the kidney normally clears a substantial fraction of circulating insulin, so doses often must be reduced to avoid hypoglycemia
B) Insulin requirements rise sharply because the kidney produces insulin that is now lost
C) Insulin requirements are unaffected by renal function at any eGFR
D) Insulin should be replaced by an SGLT-2 inhibitor as the primary agent at this eGFR
E) Insulin requirements rise because uremia enhances insulin sensitivity

ANSWER: A

Rationale:

The kidney normally degrades a substantial fraction of circulating insulin (approximately 30 to 40%), so in advanced chronic kidney disease insulin clearance falls and requirements tend to decline, frequently necessitating dose reduction to avoid hypoglycemia.

Option B: Option B is incorrect because the kidney clears insulin rather than producing it.
Option C: Option C is incorrect because renal function materially affects insulin clearance and requirements.
Option D: Option D is incorrect because SGLT-2 inhibitors lose glycemic efficacy at low eGFR and would not replace insulin as the primary glycemic agent.
Option E: Option E is incorrect because uremia is associated with insulin resistance, yet net requirements still typically fall due to reduced renal insulin clearance.

8. [CASE 2 — QUESTION 4] Continuing with the same patient. At an earlier point in her course, when her eGFR was 44 mL per minute per 1.73 m squared with persistent albuminuria despite the ACE inhibitor and SGLT-2 inhibitor, the nephrologist had added finerenone. Which statement correctly identifies finerenone's role and the key monitoring requirement?

A) Finerenone is an SGLT-2 inhibitor, so it duplicates the existing agent and requires glucose monitoring
B) Finerenone is a non-steroidal mineralocorticoid receptor antagonist that adds nephroprotection through a pathway distinct from RAAS blockade and SGLT-2 inhibition, and serum potassium must be monitored because it can cause hyperkalemia, albeit less than steroidal agents
C) Finerenone is an ACE inhibitor substitute and requires no additional monitoring
D) Finerenone lowers blood glucose directly, so hypoglycemia is the main monitoring concern
E) Finerenone constricts the efferent arteriole and requires renal artery imaging

ANSWER: B

Rationale:

Finerenone is a non-steroidal mineralocorticoid receptor antagonist that adds nephroprotection through mineralocorticoid receptor blockade, a pathway distinct from the efferent action of RAAS blockade and the afferent action of SGLT-2 inhibition; because it can raise serum potassium, potassium monitoring is required, though its hyperkalemia risk is lower than that of steroidal agents.

Option A: Option A is incorrect because finerenone is not an SGLT-2 inhibitor.
Option C: Option C is incorrect because finerenone is not an ACE inhibitor substitute and does require potassium monitoring.
Option D: Option D is incorrect because finerenone does not act by lowering blood glucose.
Option E: Option E is incorrect because finerenone does not constrict the efferent arteriole and does not require renal artery imaging.

9. [CASE 3 — QUESTION 1] A 67-year-old man with T2DM and ischemic cardiomyopathy has heart failure with reduced ejection fraction (left ventricular ejection fraction 30%, NYHA class II to III). His eGFR is 52 mL per minute per 1.73 m squared. He takes metformin plus guideline-directed heart failure therapy. The cardiology team wants a glucose-lowering agent that is also disease-modifying for his heart failure. Which agent best fits this goal?

A) Pioglitazone, which improves insulin sensitivity and benefits the failing heart
B) Saxagliptin, for its neutral-to-favorable heart failure profile
C) A long-acting sulfonylurea, which reduces heart failure events
D) An SGLT-2 inhibitor such as dapagliflozin or empagliflozin, which reduces cardiovascular death and heart failure hospitalization in heart failure with reduced ejection fraction independent of diabetes status
E) A second agent from the DPP-4 class for additive cardiac benefit

ANSWER: D

Rationale:

An SGLT-2 inhibitor such as dapagliflozin or empagliflozin is the best fit because it reduces cardiovascular death and heart failure hospitalization in heart failure with reduced ejection fraction, with benefit independent of diabetes status, making it disease-modifying for his heart failure.

Option A: Option A is incorrect because pioglitazone causes fluid retention and is contraindicated in advanced heart failure.
Option B: Option B is incorrect because saxagliptin increases heart failure hospitalization.
Option C: Option C is incorrect because sulfonylureas do not reduce heart failure events and add hypoglycemia risk.
Option E: Option E is incorrect because DPP-4 inhibitors are not disease-modifying in heart failure.

10. [CASE 3 — QUESTION 2] Continuing with the same patient. A medication reconciliation reveals that, in addition to his metformin and newly added SGLT-2 inhibitor, he is also taking saxagliptin and pioglitazone prescribed previously. Given his heart failure with reduced ejection fraction, what is the correct action regarding these two agents?

A) Discontinue both saxagliptin (associated with increased heart failure hospitalization) and pioglitazone (causes fluid retention and is contraindicated in NYHA class III to IV), since both are harmful in his heart failure
B) Continue both, since neither affects heart failure
C) Continue saxagliptin and stop only pioglitazone
D) Continue pioglitazone and stop only saxagliptin
E) Stop metformin instead, as it is the agent harmful in heart failure

ANSWER: A

Rationale:

Both agents should be discontinued: saxagliptin is associated with increased heart failure hospitalization, and pioglitazone causes sodium and water retention and is contraindicated in NYHA class III to IV heart failure.

Option B: Option B is incorrect because both agents are harmful in heart failure.
Option C: Option C is incorrect because saxagliptin must also be stopped, not only pioglitazone.
Option D: Option D is incorrect because pioglitazone must also be stopped, not only saxagliptin.
Option E: Option E is incorrect because metformin is not the heart-failure-harmful agent and may continue at his renal function.

11. [CASE 3 — QUESTION 3] Continuing with the same patient. He is admitted with acute decompensated heart failure; he is fluid-restricted, eating poorly, and started on an intravenous insulin infusion. The team asks how to manage his SGLT-2 inhibitor and what glucose target to use during the admission. Which plan is correct?

A) Continue the SGLT-2 inhibitor and target a glucose of 4.0 to 6.0 mmol/L (70 to 110 mg per deciliter)
B) Continue the SGLT-2 inhibitor and withhold insulin to limit sodium retention
C) Hold the SGLT-2 inhibitor during the admission because the fasting, fluid-restricted state raises the risk of euglycemic diabetic ketoacidosis, and target an inpatient glucose of 7.8 to 10.0 mmol/L (140 to 180 mg per deciliter) while avoiding hypoglycemia
D) Hold the SGLT-2 inhibitor but target a glucose of 4.0 to 6.0 mmol/L (70 to 110 mg per deciliter)
E) Discontinue insulin and resume the SGLT-2 inhibitor to accelerate diuresis

ANSWER: C

Rationale:

The SGLT-2 inhibitor should be held during acute decompensated heart failure because the fasting, fluid-restricted state raises the risk of euglycemic diabetic ketoacidosis, and the recommended inpatient glucose target is 7.8 to 10.0 mmol/L (140 to 180 mg per deciliter) while avoiding hypoglycemia.

Option A: Option A is incorrect because the agent should be held and the target is not as tight as 70 to 110.
Option B: Option B is incorrect because insulin is the appropriate inpatient agent and should not be withheld.
Option D: Option D is incorrect because, although holding the SGLT-2 inhibitor is right, a 70 to 110 target is too tight and risks hypoglycemia in a critically ill patient.
Option E: Option E is incorrect because resuming the SGLT-2 inhibitor in the fasting decompensated state risks euglycemic diabetic ketoacidosis and excess volume depletion.

12. [CASE 3 — QUESTION 4] Continuing with the same patient. After stabilization he is discharged but requires large daily insulin doses, and over subsequent visits he has recurrent fluid overload. Recognizing a mechanism by which high-dose insulin can aggravate his heart failure, which adjustment is most rational?

A) Increase the insulin dose, since fluid overload reflects inadequate glycemic control
B) Recognize that high-dose insulin promotes sodium retention through renal tubular insulin receptor activation, and transition toward an SGLT-2 inhibitor-containing regimen that partially offsets insulin-mediated sodium retention and allows the insulin dose to be reduced
C) Add pioglitazone to reduce the insulin requirement
D) Add a long-acting sulfonylurea so the insulin dose can be lowered
E) Switch entirely to a DPP-4 inhibitor as monotherapy

ANSWER: B

Rationale:

High-dose insulin promotes sodium retention through renal tubular insulin receptor activation, which can worsen fluid overload in heart failure; transitioning toward an SGLT-2 inhibitor-containing regimen partially offsets this sodium retention and allows the insulin dose to be reduced.

Option A: Option A is incorrect because increasing insulin would worsen the sodium-retaining effect.
Option C: Option C is incorrect because pioglitazone itself causes fluid retention and is contraindicated in advanced heart failure.
Option D: Option D is incorrect because a sulfonylurea adds hypoglycemia risk and does not address the sodium-retention mechanism.
Option E: Option E is incorrect because a DPP-4 inhibitor alone is unlikely to control glycemia in an insulin-requiring patient and does not address the fluid problem.

13. [CASE 4 — QUESTION 1] A 30-year-old woman at 28 weeks gestation is diagnosed with gestational diabetes mellitus (GDM). After two weeks of adequate medical nutrition therapy (MNT), her fasting glucose remains 5.9 mmol/L (106 mg per deciliter) and one-hour postprandial values are repeatedly above 8.3 mmol/L (150 mg per deciliter). She has no other medical problems. Which pharmacological choice is the standard of care, and to what targets?

A) Initiate insulin, the standard of care in pregnancy, titrated to fasting below 5.3 mmol/L (95 mg per deciliter) and one-hour postprandial below 7.8 mmol/L (140 mg per deciliter)
B) Initiate empagliflozin, since SGLT-2 inhibitors are safe and effective in pregnancy
C) Initiate semaglutide for postprandial control
D) Initiate pioglitazone, which is well tolerated in all trimesters
E) Continue MNT alone indefinitely regardless of glucose values

ANSWER: A

Rationale:

Insulin is the standard of care for GDM when medical nutrition therapy fails, titrated to pregnancy targets of fasting below 5.3 mmol/L (95 mg per deciliter) and one-hour postprandial below 7.8 mmol/L (140 mg per deciliter).

Option B: Option B is incorrect because SGLT-2 inhibitors are contraindicated in the second and third trimesters.
Option C: Option C is incorrect because GLP-1R agonists lack adequate pregnancy safety data and are not recommended.
Option D: Option D is incorrect because thiazolidinediones lack pregnancy safety data.
Option E: Option E is incorrect because pharmacotherapy is indicated once glucose targets are unmet despite adequate medical nutrition therapy.

14. [CASE 4 — QUESTION 2] Continuing with the same patient. As insulin is initiated, the team selects formulations with the strongest pregnancy safety data. Which statement correctly describes preferred insulin formulations in pregnancy?

A) Regular insulin is preferred over rapid-acting analogs for postprandial control in pregnancy
B) No insulin formulation has adequate pregnancy data, so all are equally unsupported
C) Inhaled insulin is the preferred prandial option in pregnancy
D) NPH (neutral protamine Hagedorn) is the most extensively studied intermediate-acting insulin in pregnancy, insulin detemir is a preferred long-acting analog based on robust pregnancy safety data, and insulin aspart and lispro are preferred rapid-acting analogs for postprandial control
E) Premixed insulin formulations are contraindicated in all pregnancies

ANSWER: D

Rationale:

NPH (neutral protamine Hagedorn) is the most extensively studied intermediate-acting insulin in pregnancy, insulin detemir is a preferred long-acting analog based on robust pregnancy safety data, and the rapid-acting analogs insulin aspart and lispro are preferred over regular insulin for postprandial control.

Option A: Option A is incorrect because rapid-acting analogs aspart and lispro are preferred over regular insulin for postprandial control.
Option B: Option B is incorrect because several formulations do have adequate pregnancy data.
Option C: Option C is incorrect because inhaled insulin is not the preferred prandial option in pregnancy.
Option E: Option E is incorrect because premixed formulations are not categorically contraindicated, though analog-based regimens are commonly preferred for flexibility.

15. [CASE 4 — QUESTION 3] Continuing with the same patient. She has a friend who took metformin during pregnancy and asks why she was not simply given metformin instead of insulin injections. Which explanation is most accurate?

A) Metformin does not cross the placenta, so it would have been the safest choice and insulin was unnecessary
B) Metformin is the first-line agent in pregnancy and is preferred over insulin in all patients
C) Metformin is absolutely contraindicated in pregnancy because of confirmed structural teratogenicity in humans
D) Metformin and insulin are interchangeable with identical neonatal outcomes
E) Metformin crosses the placenta and reaches fetal concentrations approximating maternal levels; it is used in pregnancy only when insulin cannot be used and is not first-line, so insulin remains the standard of care

ANSWER: E

Rationale:

Metformin crosses the placenta and achieves fetal concentrations approximating maternal levels; although not associated with structural teratogenicity in human studies, follow-up data raised concerns about large-for-gestational-age neonates and childhood adiposity, so it is used only when insulin cannot be used and is not first-line, leaving insulin as the standard of care.

Option A: Option A is incorrect because metformin does cross the placenta.
Option B: Option B is incorrect because metformin is second-line, not preferred over insulin.
Option C: Option C is incorrect because metformin has not been associated with structural teratogenicity in human observational studies.
Option D: Option D is incorrect because metformin and insulin are not interchangeable; neonatal outcome differences have been observed.

16. [CASE 4 — QUESTION 4] Continuing with the same patient. She delivers a healthy infant and plans to breastfeed. The postpartum team must adjust her insulin and counsel her on future glucose-lowering options. Which plan is correct?

A) Maintain her third-trimester insulin dose unchanged and forbid all oral agents during breastfeeding
B) Reduce her insulin dose substantially at delivery because requirements fall sharply once the placenta is delivered; reassess GDM resolution at 4 to 12 weeks postpartum with a 75-gram oral glucose tolerance test, and note that if an oral agent is later needed, metformin is considered compatible with breastfeeding whereas most other oral agents have insufficient data
C) Increase her insulin dose at delivery because lactation raises glucose demand
D) Stop insulin and start semaglutide, which is the preferred breastfeeding agent
E) Start a long-acting sulfonylurea at delivery for convenience

ANSWER: B

Rationale:

Insulin requirements fall sharply within hours of placental delivery, so the dose must be reduced substantially to avoid postpartum hypoglycemia; GDM resolution should be reassessed at 4 to 12 weeks postpartum with a 75-gram oral glucose tolerance test, and if an oral agent is later needed, metformin is considered compatible with breastfeeding while most other oral agents have insufficient lactation data.

Option A: Option A is incorrect because maintaining the third-trimester dose risks severe hypoglycemia and metformin is in fact compatible with breastfeeding.
Option C: Option C is incorrect because requirements fall rather than rise after delivery.
Option D: Option D is incorrect because semaglutide is not the preferred breastfeeding agent.
Option E: Option E is incorrect because a long-acting sulfonylurea introduces hypoglycemia risk and is not the appropriate postpartum choice.

17. [CASE 5 — QUESTION 1] An 82-year-old woman with T2DM, mild cognitive impairment, and frailty is brought to clinic after a fall that was preceded by sweating, tremor, and confusion. She lives alone and frequently skips meals. Her medications include glibenclamide (glyburide) and metformin; her HbA1c is 6.5% and eGFR is 50 mL per minute per 1.73 m squared. Which initial action best addresses the most likely cause of her fall?

A) Intensify therapy to drive the HbA1c below 6.0%
B) Continue glibenclamide unchanged because the HbA1c is excellent
C) Add basal insulin to lower glucose further
D) Add a second sulfonylurea to stabilize fasting glucose
E) Stop glibenclamide, which is flagged by the Beers Criteria as potentially inappropriate in older adults and is the likely cause of her hypoglycemia and fall, given its prolonged duration of action and her irregular meals

ANSWER: E

Rationale:

Glibenclamide is flagged by the American Geriatrics Society Beers Criteria as potentially inappropriate in adults over 65 because of its prolonged duration of action and risk of severe hypoglycemia; in this frail woman with irregular meals and a hypoglycemia-related fall, it is the likely culprit and should be stopped.

Option A: Option A is incorrect because a sub-6.0% target maximizes hypoglycemia risk with negligible benefit.
Option B: Option B is incorrect because the low HbA1c reflects dangerous overtreatment in this context, not success.
Option C: Option C is incorrect because basal insulin would increase hypoglycemia risk in a patient who skips meals.
Option D: Option D is incorrect because a second sulfonylurea compounds the hypoglycemia that caused her fall.

18. [CASE 5 — QUESTION 2] Continuing with the same patient. After glibenclamide is stopped, the team sets a new glycemic target appropriate to her age, frailty, and cognitive status. Which target and rationale are most appropriate?

A) HbA1c below 6.5%, because tight control benefits all older adults equally
B) HbA1c below 6.0%, to prevent any microvascular progression
C) No glycemic target is needed in older adults
D) A less stringent HbA1c of approximately 7.5 to 8.0% (or up to 8.5% with significant frailty or limited life expectancy), because hypoglycemia avoidance and preserved function take precedence over tight control in this population
E) HbA1c below 7.0% achieved by escalating insulin regardless of hypoglycemia risk

ANSWER: D

Rationale:

For an older adult with frailty and cognitive impairment, the American Diabetes Association stratifies targets by functional status, and a less stringent HbA1c of roughly 7.5 to 8.0% (or up to 8.5% with significant frailty or limited life expectancy) is appropriate because hypoglycemia avoidance and preserved function take precedence over tight control.

Option A: Option A is incorrect because tight control does not benefit all older adults equally and raises hypoglycemia harm.
Option B: Option B is incorrect because a sub-6.0% target maximizes hypoglycemia risk.
Option C: Option C is incorrect because a reasonable individualized target still matters for symptoms and safety.
Option E: Option E is incorrect because aggressive insulin escalation ignoring hypoglycemia risk is inappropriate in this population.

19. [CASE 5 — QUESTION 3] Continuing with the same patient. She needs an additional agent beyond metformin to maintain her relaxed glycemic target, and the team wants an option with minimal hypoglycemia risk that is well tolerated in the elderly. Which choice best fits?

A) A long-acting sulfonylurea, since it is inexpensive and effective
B) High-dose prandial insulin to cover all meals
C) A dipeptidyl peptidase-4 (DPP-4) inhibitor, which is weight neutral, has minimal hypoglycemia risk as monotherapy, requires only dose adjustment (not discontinuation) for renal impairment with most agents, and has a low daily pill burden
D) Glibenclamide restarted at a lower dose
E) A rapid up-titration of basal insulin to normalize fasting glucose

ANSWER: C

Rationale:

A DPP-4 inhibitor is well suited to this frail elderly patient because it is weight neutral, carries minimal hypoglycemia risk as monotherapy, requires only dose adjustment (not discontinuation) for renal impairment with most agents, and has a low daily pill burden.

Option A: Option A is incorrect because a long-acting sulfonylurea carries high hypoglycemia risk in the elderly.
Option B: Option B is incorrect because high-dose prandial insulin maximizes hypoglycemia risk in a patient with irregular meals.
Option D: Option D is incorrect because glibenclamide is the agent just stopped for causing hypoglycemia and is Beers-flagged.
Option E: Option E is incorrect because rapid basal insulin up-titration to normalize fasting glucose raises hypoglycemia risk against her relaxed target.

20. [CASE 5 — QUESTION 4] Continuing with the same patient. Months later, while briefly on a sulfonylurea again during a transition of care, she develops severe hypoglycemia shortly after starting a new medication for an infection. Which co-prescribed class is a recognized precipitant of severe sulfonylurea-associated hypoglycemia and the most likely contributor?

A) An antimicrobial such as a fluoroquinolone or trimethoprim, which can interact with sulfonylureas to precipitate severe hypoglycemia
B) An inhaled corticosteroid, which displaces sulfonylureas from muscle receptors
C) A proton pump inhibitor, which doubles sulfonylurea renal clearance
D) A calcium channel blocker, which directly stimulates insulin release
E) A loop diuretic, which enhances sulfonylurea metabolism

ANSWER: A

Rationale:

Antimicrobials such as fluoroquinolones and trimethoprim (as well as azole antifungals and fibrates) are recognized precipitants of severe sulfonylurea-associated hypoglycemia, making a newly started antibiotic the most likely contributor here; medication reconciliation at every encounter is essential in elderly polypharmacy.

Option B: Option B is incorrect because inhaled corticosteroids tend to raise glucose and do not displace sulfonylureas from muscle receptors.
Option C: Option C is incorrect because proton pump inhibitors do not double sulfonylurea renal clearance.
Option D: Option D is incorrect because calcium channel blockers do not directly stimulate insulin release or cause sulfonylurea hypoglycemia.
Option E: Option E is incorrect because loop diuretics tend to raise glucose rather than enhance sulfonylurea metabolism.

21. [CASE 6 — QUESTION 1] A 76-year-old man with T2DM has an unusually convergent set of comorbidities: established atherosclerotic cardiovascular disease (prior stroke), heart failure with reduced ejection fraction (ejection fraction 38%), and diabetic kidney disease (eGFR 40 mL per minute per 1.73 m squared with a urinary albumin-to-creatinine ratio of 350 mg per gram). He is on metformin and a maximally tolerated angiotensin receptor blocker (ARB). The team seeks one additional agent that simultaneously addresses his heart failure and his kidney disease. Which single class best accomplishes this?

A) A dipeptidyl peptidase-4 (DPP-4) inhibitor, which provides renal and heart failure outcome benefit
B) An SGLT-2 inhibitor, which slows diabetic kidney disease progression and reduces heart failure hospitalization and cardiovascular death, addressing both comorbidities with one agent and remaining usable at this eGFR
C) A thiazolidinedione, which protects the kidney and improves heart failure
D) A long-acting sulfonylurea, which is renoprotective and reduces heart failure events
E) High-dose insulin, which is disease-modifying for both kidney disease and heart failure

ANSWER: B

Rationale:

An SGLT-2 inhibitor uniquely addresses both his heart failure and his kidney disease: it slows diabetic kidney disease progression through afferent arteriolar pressure reduction and reduces heart failure hospitalization and cardiovascular death, with usability at this eGFR.

Option A: Option A is incorrect because DPP-4 inhibitors are cardiovascular-neutral and not disease-modifying for kidney disease or heart failure.
Option C: Option C is incorrect because thiazolidinediones cause fluid retention and are contraindicated in heart failure with reduced ejection fraction.
Option D: Option D is incorrect because sulfonylureas are neither renoprotective nor beneficial in heart failure and add hypoglycemia risk.
Option E: Option E is incorrect because insulin is not disease-modifying for kidney disease or heart failure.

22. [CASE 6 — QUESTION 2] Continuing with the same patient. After the SGLT-2 inhibitor is established and his heart failure and kidney parameters stabilize, the team turns to his atherosclerotic risk given his prior stroke. Which addition most directly targets his residual atherosclerotic risk, and what is the rationale for combining it with his current SGLT-2 inhibitor?

A) Add pioglitazone, since it reduces stroke risk through PPAR-gamma activation
B) Add saxagliptin, since DPP-4 inhibitors reduce atherosclerotic events
C) Add a long-acting sulfonylurea, since tighter control reduces stroke recurrence
D) Add nothing further, since the SGLT-2 inhibitor already covers atherosclerotic events
E) Add a GLP-1R agonist, which reduces atherosclerotic events including stroke, complementing the SGLT-2 inhibitor's heart failure and renal benefit to provide dual-pathway protection

ANSWER: E

Rationale:

A GLP-1R agonist most directly targets his residual atherosclerotic risk because the class reduces atherosclerotic events, including stroke, and combining it with his SGLT-2 inhibitor delivers dual-pathway protection: anti-atherosclerotic benefit from the GLP-1R agonist and hemodynamic heart failure and renal benefit from the SGLT-2 inhibitor.

Option A: Option A is incorrect because pioglitazone does not reduce stroke risk and is contraindicated in his heart failure.
Option B: Option B is incorrect because DPP-4 inhibitors are cardiovascular-neutral.
Option C: Option C is incorrect because sulfonylurea-driven glycemic control does not reduce stroke recurrence and adds hypoglycemia risk.
Option D: Option D is incorrect because the SGLT-2 inhibitor reduces heart failure and cardiovascular death but not the atherosclerotic events that a GLP-1R agonist addresses.

23. [CASE 6 — QUESTION 3] Continuing with the same patient. Despite the ARB and SGLT-2 inhibitor, his albuminuria persists and the nephrologist considers adding finerenone for triple nephroprotective therapy. His current serum potassium is 4.9 mmol/L. Which consideration is most important before and during finerenone initiation?

A) No monitoring is required, since finerenone does not affect electrolytes
B) Monitor for hypoglycemia, since finerenone lowers glucose
C) Monitor serum potassium closely, because finerenone is a mineralocorticoid receptor antagonist added on top of RAAS blockade and can raise potassium, and his baseline potassium is already in the upper-normal range; the combination targets residual albuminuria through a distinct pathway with a more favorable hyperkalemia profile than steroidal agents
D) Monitor liver enzymes for hepatotoxicity, the characteristic finerenone risk
E) Stop the ARB and replace it with finerenone, since they act identically

ANSWER: C

Rationale:

The most important consideration is close serum potassium monitoring, because finerenone is a mineralocorticoid receptor antagonist added on top of RAAS blockade and can raise potassium, especially with a baseline already in the upper-normal range; the triple combination targets residual albuminuria through a distinct pathway and, as a non-steroidal agent, finerenone carries a more favorable hyperkalemia profile than steroidal mineralocorticoid receptor antagonists.

Option A: Option A is incorrect because finerenone can raise potassium and monitoring is required.
Option B: Option B is incorrect because finerenone does not lower glucose.
Option D: Option D is incorrect because hepatotoxicity is not the characteristic concern.
Option E: Option E is incorrect because finerenone is added to, not substituted for, RAAS blockade and acts through a different receptor.

24. [CASE 6 — QUESTION 4] Continuing with the same patient. Two years later, at age 78, he has declining food intake, weight loss, and worsening frailty; his goals of care shift toward comfort and minimizing treatment burden. His regimen has grown to metformin, an SGLT-2 inhibitor, a GLP-1R agonist, finerenone, basal insulin, and a sulfonylurea added during a hospitalization. Which deprescribing approach is most appropriate as an initial step?

A) Continue all agents unchanged, since each was individually indicated
B) Stop the SGLT-2 inhibitor and finerenone first, since renal and cardiac protection no longer matter at all
C) Intensify insulin to maintain tight control despite reduced intake
D) Begin deprescribing by stopping the sulfonylurea first (highest hypoglycemia risk with declining intake) and reducing or stopping the GLP-1R agonist given its appetite-suppressing effect in a patient with weight loss and poor intake, while relaxing glycemic targets toward comfort
E) Stop metformin alone and make no other changes

ANSWER: D

Rationale:

As goals shift toward comfort in an frail elderly patient with declining intake and weight loss, deprescribing should begin by stopping the sulfonylurea first because it carries the highest hypoglycemia risk in the setting of poor intake, and by reducing or stopping the GLP-1R agonist because its appetite-suppressing effect is harmful in a patient already losing weight, while glycemic targets are relaxed toward comfort.

Option A: Option A is incorrect because continuing all agents ignores the shifted harm-benefit balance and hypoglycemia risk.
Option B: Option B is incorrect because the SGLT-2 inhibitor and finerenone are not the highest-priority agents to stop first and may still offer symptomatic and protective value.
Option C: Option C is incorrect because intensifying insulin with reduced intake raises hypoglycemia risk.
Option E: Option E is incorrect because stopping metformin alone does not address the higher-risk sulfonylurea and appetite-suppressing GLP-1R agonist.