STEPTRACKERPHARMACOLOGY + ENDOCRINOLOGY | ENDOCRINE | HIGH-YIELD REVIEW

Pituitary, Bone & Calcium Drugs

Hypothalamic and pituitary analogs replace or suppress hormones; bone drugs either slow resorption or build new bone; calcium drugs fix the parathyroid axis.

FOCUS ON
Somatostatin analogs (octreotide, lanreotide): acromegaly, carcinoid, VIPoma, variceal bleeding; gallstones, steatorrhea. Pegvisomant: GH-receptor antagonist. GH (somatropin): deficiency, Turner, Prader-Willi. Desmopressin (V2): central DI, enuresis, vWD/hemophilia A; hyponatremia. Vasopressin: shock, variceal bleeding. Oxytocin: labor induction, postpartum hemorrhage; water intoxication. Cabergoline/bromocriptine (D2 agonists): prolactinoma. GnRH analogs: continuous (leuprolide) suppresses → prostate cancer, endometriosis, precocious puberty (initial flare); pulsatile stimulates → infertility. Bisphosphonates (alendronate, zoledronate): bind hydroxyapatite → osteoclast apoptosis; pill esophagitis (upright 30 min), osteonecrosis of jaw, atypical femur fracture. Denosumab (RANKL antibody). Teriparatide/abaloparatide (intermittent PTH analogs): anabolic. Romosozumab (sclerostin). Raloxifene (SERM). Calcitonin. Cinacalcet.
DRUG
MECHANISM
USE
ADVERSE · NOTES
Octreotide · lanreotide
Somatostatin analogs (↓ GH, insulin, glucagon, gut hormones, splanchnic flow)
Acromegaly, carcinoid syndrome, VIPoma, esophageal varices
Cholesterol gallstones, steatorrhea, hypoglycemia/hyperglycemia
Pegvisomant
GH receptor antagonist (↓ IGF-1)
Acromegaly refractory to surgery/octreotide
↑ LFTs
Somatropin
Recombinant GH
GH deficiency, Turner, Prader-Willi, CKD short stature
SCFE, pseudotumor cerebri, hyperglycemia
Desmopressin
V2 agonist
Central DI, nocturnal enuresis, hemophilia A, type 1 vWD
Hyponatremia, seizures
Vasopressin
V1 (vasoconstriction) + V2
Septic shock (add-on), variceal bleeding
Ischemia
Oxytocin
Uterine contraction, milk let-down
Labor induction/augmentation, postpartum hemorrhage
Uterine hyperstimulation, hyponatremia (ADH-like)
Cabergoline · bromocriptine
D2 agonists → ↓ prolactin
Prolactinoma, acromegaly adjunct, Parkinson (bromocriptine)
Nausea, orthostasis; cabergoline valvulopathy (high dose)
Leuprolide · goserelin (continuous)
GnRH agonists → downregulate pituitary receptors
Prostate cancer, breast cancer, endometriosis, fibroids, precocious puberty
Initial flare (add flutamide), hot flashes, bone loss
Degarelix · elagolix · relugolix
GnRH antagonists — no flare
Prostate cancer, endometriosis
Hot flashes
Bisphosphonates
Pyrophosphate analogs → osteoclast inhibition
Osteoporosis, Paget disease, hypercalcemia of malignancy, bone metastases
Pill esophagitis, jaw osteonecrosis, atypical femur fractures, hypocalcemia
Denosumab
Monoclonal antibody to RANKL
Osteoporosis, bone metastases
Hypocalcemia, jaw osteonecrosis, rebound fractures after stopping
Teriparatide · abaloparatide
Intermittent PTH/PTHrP analog → ↑ osteoblast activity
Severe osteoporosis
Osteosarcoma (animal), transient hypercalcemia; avoid in Paget, prior radiation
Romosozumab
Anti-sclerostin → ↑ formation, ↓ resorption
Severe osteoporosis
MI and stroke risk
Calcitonin
↓ Osteoclast activity
Acute hypercalcemia (rapid, tachyphylaxis), Paget
Short-lived effect

Mechanism — continuous vs pulsatile GnRH

Pulsatile GnRH
→
↑ LH, FSHOvulation induction
Continuous agonist
→
Brief flare, then receptor downregulation
→
↓ LH, FSH → ↓ testosterone, estrogen

Hypercalcemia of malignancy

STEP
DRUG
ONSET
Volume
IV normal saline
Hours
Fast
Calcitonin
Hours (fades in 48 h)
Lasting
Zoledronate / denosumab
2–4 days
Vit D–mediated
Glucocorticoids
Days

How it's tested

COMMON CONFUSIONPTH is catabolic when continuously high (hyperparathyroidism) but anabolic when given intermittently (teriparatide).
THE TRAPStarting leuprolide alone in metastatic prostate cancer can transiently worsen bone pain or cord compression — add an antiandrogen first.
YOUR APPROACHPituitary problem → replace (GH, ADH, cortisol) or suppress (octreotide, cabergoline). Bone → antiresorptive first; anabolic for severe disease.

If you see… think…

Retrosternal pain after a weekly osteoporosis pill → bisphosphonate esophagitis
Exposed jawbone after dental extraction → bisphosphonate or denosumab
Anabolic osteoporosis drug given daily by injection → teriparatide
Prolactinoma first-line → cabergoline
Gallstones after acromegaly drug → octreotide
Bedwetting child, nasal spray → desmopressin
Hyponatremia during labor induction → oxytocin (ADH-like)
Bone pain flare after starting prostate cancer drug → GnRH agonist flare
Hypocalcemia after an injection every 6 months → denosumab
Variceal bleeding, ↓ splanchnic flow → octreotide