PT
● MODULE 13 / 20
Endocrine & Metabolic Pharmacology
Study insulin, glucose-lowering drugs, thyroid therapy and adrenal, pituitary and bone pharmacology.
Quick revision ↓ Medical Dictionary
FULL CHAPTER EXPLANATION
Deep Learning — Module 13
Read this section in sequence. It moves from drug targets to therapeutic effects, adverse reactions and safe use.
01
Insulin and glucose regulation
Insulin activates a receptor tyrosine kinase and promotes nutrient storage, glucose uptake in responsive tissues and intracellular potassium movement. Preparations differ in onset and duration, permitting basal and meal-related replacement strategies. Hypoglycemia is the major immediate risk; timing, food intake, exercise and renal function affect it. Insulin is essential in type 1 diabetes. A numerical glucose target is meaningful only in a patient-specific plan that balances benefit against hypoglycemia risk.
02
Non-insulin glucose-lowering drugs
Metformin chiefly reduces hepatic glucose production and usually does not cause hypoglycemia when used alone. Sulfonylureas close beta-cell ATP-sensitive potassium channels to promote insulin release and can cause hypoglycemia. GLP-1 receptor agonists enhance glucose-dependent insulin responses and affect satiety and gastric emptying; DPP-4 inhibitors prolong endogenous incretin action. SGLT2 inhibitors increase urinary glucose loss and have important cardiorenal roles in selected patients, but can cause genital infections and ketoacidosis with less marked hyperglycemia. Each class has distinct precautions.
03
Thyroid and antithyroid therapy
Levothyroxine supplies T4 and is monitored with thyroid-function testing interpreted in the appropriate pituitary-thyroid context. Iron and calcium can impair its absorption if taken too close together. Thionamides such as carbimazole or methimazole inhibit thyroid peroxidase; propylthiouracil also reduces peripheral T4-to-T3 conversion. Agranulocytosis and hepatic toxicity are serious class-related concerns with differing risk profiles. Radioiodine destroys thyroid tissue and is not appropriate in pregnancy; beta blockade can reduce adrenergic symptoms without stopping hormone synthesis.
04
Glucocorticoids and mineralocorticoids
Glucocorticoids alter gene expression, suppress inflammation and replace deficient cortisol. Long-term systemic exposure can cause hyperglycemia, infection risk, osteoporosis and hypothalamic-pituitary-adrenal suppression. Abrupt withdrawal after significant suppression may precipitate adrenal insufficiency, so withdrawal is individualized. Fludrocortisone provides mineralocorticoid effects in selected deficiency states and can cause fluid retention and hypokalemia. Replacement doses and anti-inflammatory doses serve different purposes.
05
Pituitary and bone medicines
Dopamine agonists such as cabergoline reduce prolactin release; somatostatin analogues suppress selected hormone secretion. Growth hormone replacement has defined indications and requires specialist monitoring. Bisphosphonates inhibit osteoclast-mediated bone resorption; oral formulations have administration requirements to reduce esophageal injury. Calcium, vitamin D and anabolic bone agents have different roles. Drug choice requires identifying the physiological deficit or excess rather than assuming every hormonal disorder is treated by replacement.
High-Yield Revision
- Sulfonylureas and insulin can cause hypoglycemia; metformin alone usually does not.
- Corticosteroid withdrawal risk depends on exposure and adrenal suppression.
- A glucose value that is not very high does not exclude SGLT2-associated ketoacidosis.
Common Exam & Concept Pitfalls
- Beta blockers reduce thyrotoxic symptoms but do not directly stop thyroid hormone synthesis.
- Do not assume every osteoporosis medicine builds bone through the same mechanism.
Sources & Further Reading
Curriculum scope checked 23 September 2026. These original study notes summarize established principles; current institutional guidance and product information govern clinical use. Faculty review is pending.
RAHBAR study structure: target → drug action → therapeutic use → adverse effects → monitoring. Use institutional curriculum and faculty guidance for local sequencing, practical requirements and assessment specifications.