6 Endocrine Pharmacology: Integrated Review

Principles of safe medication use

Safe endocrine pharmacotherapy depends on matching medication choice and monitoring to comorbidities, kidney function, glucose patterns, and medication-specific risks. Treatment decisions also depend on the individual’s clinical circumstances and prescribed plan.

Insulin, meals, and low blood glucose

Meal-related insulin is intended to cover food. If nausea prevents a person with type 1 diabetes from eating, taking the usual meal dose may cause hypoglycemia. Follow the individualized sick-day and correction-dose plan, and check glucose as directed. Do not stop basal insulin in type 1 diabetes without clinician direction.

People using insulin need education about glucose monitoring and the prevention and treatment of hypoglycemia. Sulfonylureas such as glipizide can also cause hypoglycemia, and skipping or delaying a meal can make that risk more apparent. Review meal planning and the medication plan with the prescriber or care team rather than taking an extra dose or relying on symptoms alone.

Diabetes medicines and kidney or heart conditions

For type 2 diabetes with chronic kidney disease or heart failure, an SGLT2 inhibitor with demonstrated benefit may be appropriate for kidney and heart-failure protection, rather than solely for glucose lowering. Metformin is generally not used when eGFR is below $\frac{30\,\text{mL}}{\text{min}\cdot1.73\,\text{m}^2}$. For example, an eGFR of $\frac{28\,\text{mL}}{\text{min}\cdot1.73\,\text{m}^2}$ is below that threshold. Individual medication choice, kidney-function limits, and monitoring still matter; treatment should not be selected only by comparing effects on A1C.

SGLT2 inhibitor-associated ketoacidosis can occur without marked hyperglycemia. Nausea, vomiting, abdominal pain, and rapid breathing during illness warrant urgent assessment, including ketone evaluation, even when glucose is $185\,\text{mg/dL}$. Do not assume ketoacidosis is impossible because glucose is below $250\,\text{mg/dL}$. If ketoacidosis is suspected, the SGLT2 inhibitor should be stopped and prompt treatment sought.

Thyroid medication use and warning signs

Food and calcium can reduce levothyroxine absorption. Take it consistently on an empty stomach and separate calcium according to clinician or pharmacist guidance. After administration changes, a clinician may reassess thyroid tests and the dose.

Fever or severe sore throat while taking methimazole may signal a dangerously low white blood cell count (agranulocytosis). Seek medical evaluation promptly, including a blood count, and do not take further doses until the treating clinician advises whether to restart.

Glucocorticoids and blood glucose

Morning prednisone can cause glucose to rise after breakfast, with higher readings in the afternoon and evening, even when fasting glucose remains close to usual. Monitoring only fasting glucose may miss this pattern. Monitoring and any treatment adjustment should account for glucose readings and the steroid’s dose and timing. As the steroid dose is tapered, glucose-lowering treatment may also need reassessment.

After prolonged oral corticosteroid use, do not stop suddenly without a prescriber-directed plan. Prolonged use can suppress natural cortisol production, and abrupt discontinuation may cause serious illness, including adrenal crisis. A taper or other plan must be determined by the prescriber; seek guidance before changing the dose.

Desmopressin and fluid balance

Desmopressin reduces urine output. Excess fluid intake while its effect is active can cause water retention and hyponatremia. Headache, nausea, confusion, and recent weight gain are warning signs that require prompt medical assessment. Follow prescribed fluid guidance and monitoring instructions, and review fluid intake and treatment with a clinician when these symptoms occur.