Adrenocorticosteroid Pharmacology · Module 2 of 4

Glucocorticoid Clinical Pharmacology: Immunosuppression and Organ-Specific Applications

Anti-inflammatory targets, immune cell effects, critical illness dosing, and stress-dose protocol

Glucocorticoids suppress NF-κB through three parallel mechanisms simultaneously — (1) GR monomer tethers to p65, blocking coactivator binding; (2) GR induces I-κB-α transcription, sequestering NF-κB in the cytoplasm; (3) GR recruits HDAC2 to promoters, closing chromatin; the HDAC2 mechanism explains glucocorticoid resistance in COPD/smokers, where oxidative stress inactivates HDAC2 in airway macrophages; in addition, GR induces MKP-1 (MAP kinase phosphatase-1), accelerating cytokine mRNA decay post-transcriptionally by inactivating p38 MAPK and JNK kinases that normally stabilize TNF-α and IL-6 mRNA.
Neutrophilia in glucocorticoid-treated patients is redistribution, not enhanced antimicrobial function — adhesion molecule downregulation (L-selectin, Mac-1) causes demargination from endothelium; bone marrow releases mature neutrophils; rising neutrophil count cannot be used as a reliable marker of bacterial infection; eosinopenia is the most sensitive indicator of GR engagement and a useful compliance check; rising eosinophils in a patient who should be therapeutically suppressed suggests non-compliance or inadequate dosing.
Septic shock glucocorticoid indications are narrow — ADRENAL trial: hydrocortisone 200 mg/day = faster shock reversal but no mortality benefit; APROCCHSS trial: hydrocortisone + fludrocortisone = mortality benefit in more severe shock (norepinephrine >0.25 mcg/kg/min); current synthesis: use in shock refractory to adequate fluids and vasopressors; RECOVERY trial (COVID-19 ARDS): dexamethasone 6 mg daily ×10 days reduces 28-day mortality in patients requiring oxygen/ventilation (NNT ~8 ventilated); no benefit (trend toward harm) in patients not requiring oxygen.
Giant cell arteritis: never delay for biopsy when visual symptoms are present — IV methylprednisolone pulse immediately if visual symptoms or transient monocular blindness; even 24 hours' delay can cause permanent blindness from anterior ischemic optic neuropathy; temporal artery biopsy findings persist for 1–2 weeks after starting steroids; tocilizumab (IL-6 receptor antagonist) enables faster taper with fewer relapses than prednisone monotherapy.
Perioperative stress dosing is risk-stratified, not universal — no supplementation needed for prednisone <5 mg/day (any duration) or any steroid <3 weeks or off glucocorticoids >3 months; full supplementation for prednisone >20 mg/day >3 weeks or Cushingoid features; minor surgery: usual dose only; moderate: hydrocortisone 50 mg IV at induction then 25 mg q8h ×24h; major: 100 mg IV then 50 mg q8h ×24–48h; emergency with unknown HPA status: hydrocortisone 100 mg IV empirically without delay.

Abbreviations: NF-κB = nuclear factor kappa-B · GR = glucocorticoid receptor · HDAC2 = histone deacetylase 2 · MKP-1 = MAP kinase phosphatase-1 · I-κB = inhibitor of kappa-B · IL = interleukin · TNF-α = tumor necrosis factor-alpha · iNOS = inducible nitric oxide synthase · ICAM-1 = intercellular adhesion molecule-1 · MHC = major histocompatibility complex · HPA = hypothalamic-pituitary-adrenal · DMARD = disease-modifying antirheumatic drug · GCA = giant cell arteritis · PMR = polymyalgia rheumatica · SLE = systemic lupus erythematosus · ICS = inhaled corticosteroid

Anti-Inflammatory Mechanisms and Immune Cell Effects

Eicosanoid and Cytokine Suppression

Five Convergent Mechanisms

Annexin-A1 induction → inhibits cytosolic PLA2 → reduces arachidonic acid for ALL eicosanoid pathways (PG, TXA2, leukotrienes) — broader than NSAIDs (COX only)
GR tethers to NF-κB p65 → blocks coactivator binding (transrepression)
Induces I-κB-α transcription → sequesters NF-κB in cytoplasm
Recruits HDAC2 to promoters → closes chromatin; HDAC2 inactivated by oxidative stress in COPD/smokers → glucocorticoid resistance
Induces MKP-1 → inactivates p38 MAPK and JNK → accelerates cytokine mRNA decay (TNF-α, IL-6) — post-transcriptional mechanism
Cytokines suppressed: IL-1β, IL-2, IL-6, IL-8, TNF-α, IFN-γ, iNOS, ICAM-1, E-selectin

Immune Cell Effects — CBC Interpretation

Redistribution, Not Enhanced Function

Neutrophilia (2–3×): L-selectin/Mac-1 downregulation → demargination + marrow release; NOT a sign of infection in steroid-treated patients; left-shifted neutrophilia with toxic granulations suggests superimposed infection
Lymphopenia (T cells 70–90%): redistribution to lymphoid tissues + IL-2 suppression blocks clonal expansion; reverses within 24 h of a single dose
Eosinopenia: GR-mediated apoptosis; most sensitive indicator of GR engagement; rising eosinophil count in steroid-treated patient = suspect non-compliance or inadequate dosing
Macrophage impairment: ↓ MHC class II, respiratory burst, IL-1β/TNF-α/IL-12 → increased susceptibility to intracellular pathogens (TB, fungi, Listeria)
Dendritic cell maturation impaired: ↓ CD80/CD86 → reduced naive T cell priming

Critical Illness, Rheumatology, and Organ-Specific Dose Landmarks

Indication	Agent / Dose	Evidence / Key Points
Septic shock	Hydrocortisone 200 mg/day (CI or 50 mg q6h)	Only if refractory to fluids + vasopressors (>0.25 mcg/kg/min NE); ADRENAL: no mortality benefit but faster shock reversal; APROCCHSS: + fludrocortisone → mortality benefit in more severe shock; dexamethasone NOT appropriate (no MC activity)
COVID-19 ARDS	Dexamethasone 6 mg daily ×10 days	RECOVERY trial: mortality ↓ in patients requiring O₂ or ventilation (NNT ~8 for ventilated); no benefit and trend toward harm if no O₂ required; benefit when dysregulated host inflammation, not active viral replication, is dominant
Cerebral edema (tumor)	Dexamethasone 4–16 mg/day	Zero MC activity (avoids Na retention); long t½ enables twice or four-times daily dosing; NOT effective in cytotoxic edema from ischemic stroke
Bacterial meningitis	Dexamethasone 0.15 mg/kg q6h ×4 days	Give with or immediately before first antibiotic dose; reduces sensorineural hearing loss by suppressing subarachnoid inflammatory response to bacterial lysis
Giant cell arteritis	Prednisone 40–60 mg/day; IV methylprednisolone pulse if visual symptoms	Never delay if visual symptoms or transient monocular blindness — even 24 h delay can cause permanent blindness (anterior ischemic optic neuropathy); biopsy findings persist 1–2 weeks; tocilizumab enables faster taper
PMR	Prednisone 15–25 mg/day; taper over 12–24 months	Dramatic symptom relief within days (near-diagnostic); high relapse rate with premature taper
SLE (organ-threatening)	IV methylprednisolone 500–1000 mg ×3 days; then prednisone 1 mg/kg/day + mycophenolate or cyclophosphamide	Mild flares: prednisone 20–30 mg/day short course; organ-threatening (nephritis, neuropsychiatric): IV pulse + steroid-sparing immunosuppressant
Organ transplant	Triple immunosuppression: prednisone + calcineurin inhibitor + antiproliferative	Synergistic with calcineurin inhibitors (cyclosporine/tacrolimus); steroid-minimization protocols taper to off within 3–12 months in low-risk kidney recipients; rifampin/anticonvulsants can precipitate acute rejection via CYP3A4 induction

Perioperative Stress-Dose Protocol and Who Needs It

Risk stratification: No supplementation needed for prednisone equivalent <5 mg/day (any duration), any steroid <3 weeks, or off glucocorticoids >3 months. Full supplementation required for prednisone >20 mg/day for >3 weeks or any patient with Cushingoid features. Moderate-dose patients (5–20 mg/day for ≥3 weeks): supplement proportional to surgical stress.

Protocol by surgical category: Minor surgery (local/regional, same-day) → continue usual dose only; give as IV hydrocortisone equivalent if NPO. Moderate surgery (general anesthesia, 1–2 day stay) → hydrocortisone 50 mg IV at induction, then 25 mg IV q8h ×24h; resume oral when tolerating diet. Major surgery (prolonged, ICU anticipated) → hydrocortisone 100 mg IV at induction, then 50 mg IV q8h ×24–48h, taper over 48–72h; extend if fever, hypotension, or active infection. Emergency with unknown HPA status → hydrocortisone 100 mg IV empirically; do not delay for cortisol testing; draw cortisol + ACTH before dose if timing allows; hemodynamic improvement in 30–60 min supports diagnosis.

ICS considerations: standard adult doses have favorable safety profile; fluticasone propionate >500 mcg/day produces measurable HPA suppression, posterior subcapsular cataracts, and skin thinning; ciclesonide is an inactive prodrug activated by airway esterases; beclomethasone is not a CYP3A4 substrate (preferred in ritonavir-treated patients). Topical glucocorticoid potency: Class I (clobetasol) = superpotent — limit 2 consecutive weeks, avoid face/groin/axillae; Class VI–VII (hydrocortisone 1%, desonide) = safe for face and children; ointments > creams > lotions for penetration.

Suggested References

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Katzung BG, ed.	Basic and Clinical Pharmacology, 15th ed. — Chapter 40: Estrogens, Progestins, and the Female Reproductive Tract	McGraw-Hill; 2021
Brunton L, Knollmann B, Hilal-Dandan R, eds.	Goodman & Gilman’s The Pharmacological Basis of Therapeutics, 14th ed. — Chapter 44: Estrogens and Progestins	McGraw-Hill; 2023
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Chrousos GP.	Adrenocorticosteroids and adrenocortical antagonists. In: Katzung BG, ed. Basic and Clinical Pharmacology, 14th ed.	McGraw-Hill; 2018:687–710
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Annane D et al.	Hydrocortisone plus fludrocortisone for adults with septic shock (APROCCHSS)	N Engl J Med. 2018;378(9):809–818
RECOVERY Collaborative Group; Horby P et al.	Dexamethasone in hospitalized patients with COVID-19	N Engl J Med. 2021;384(8):693–704
Czock D et al.	Pharmacokinetics and pharmacodynamics of systemically administered glucocorticoids	Clin Pharmacokinet. 2005;44(1):61–98
Stone JH et al.	Trial of tocilizumab in giant-cell arteritis	N Engl J Med. 2017;377(4):317–328
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Venkatesh B et al.	Adjunctive glucocorticoid therapy in patients with septic shock (ADRENAL)	N Engl J Med. 2018;378(9):797–808