Hydrocortisone Acetate

What It Is

Mechanism of Action

1. Passive diffusion across the cell membrane
2. Binding to cytoplasmic GR, which is held in an inactive complex with heat-shock proteins (hsp90, hsp40, FKBP5)
3. Hormone binding causes conformational change → dissociation from hsp complex → receptor dimerization
4. The ligand-receptor dimer is translocated to the nucleus, where it binds glucocorticoid response elements (GREs) in gene promoters
5. Transactivation (inducing anti-inflammatory mediators like lipocortin/annexin-1, which inhibits phospholipase A2) and transrepression (suppressing NF-κB, AP-1, and pro-inflammatory genes for cytokines, COX-2, iNOS)

• Katzung's Basic and Clinical Pharmacology, 16th ed., pp. 1100-1105
• Fitzpatrick's Dermatology, Vol 1-2, Pharmacology and Mechanism of Action section

Pharmacokinetics

• Mulholland & Greenfield's Surgery, 7th ed.
• Katzung's Basic and Clinical Pharmacology, 16th ed.

Available Formulations

• The Harriet Lane Handbook, 23rd ed., p. 1173

Clinical Indications

1. Dermatology (Most Common Use)

• Mild-moderate eczema/atopic dermatitis, contact dermatitis, seborrheic dermatitis
• Mild psoriasis (low-potency areas: face, skin folds)
• Insect bite reactions, pruritus
• Classified as a Group 1 (low potency), non-methylated, non-halogenated topical corticosteroid in the dermatology classification system
• Dermatology 2-Volume Set 5th ed., Classification of topical corticosteroids

2. Anorectal Conditions

• Hemorrhoids - rectal cream (1%, 2.5%) BID or suppository 25-30 mg PR BID x 2 weeks
• Ulcerative colitis (mild/moderate) - rectal enema 100 mg once daily-BID x 2-3 weeks

3. Otolaryngology (in combination)

• Otitis externa - combined with antibiotics (e.g., polymyxin B-neomycin-hydrocortisone otic drops); avoid with perforated tympanic membrane due to ototoxicity risk from neomycin
• Ciprofloxacin-hydrocortisone is a safer alternative when perforation is possible
• Harrison's Principles of Internal Medicine, 22nd ed.

4. Intra-articular / Soft Tissue Injection

• Small to medium joints - bursitis, tenosynovitis
• CPT/HCPCS code: J1700 (Hydrocortisone Acetate)
• Pfenninger & Fowler's Procedures for Primary Care, 3rd ed.

5. Pruritus (in combination)

• Combined with pramoxine 1% (cream, lotion, gel) for symptomatic relief of pruritus - apply 2-4x daily
• Katzung's Basic and Clinical Pharmacology, 16th ed.

6. Adrenal Insufficiency / Stress Dosing

• Physiologic replacement: hydrocortisone base is preferred (not the acetate formulation) for oral/IV use
• In adrenal insufficiency, total daily replacement typically should not exceed 20 mg/day (divided doses)
• Caution: hydrocortisone acetate interferes with cortisol immunoassays - use dexamethasone for empiric replacement when adrenal testing is pending
• Harrison's Principles of Internal Medicine, 22nd ed.

Dosing Summary (Pediatric & Adult)

• The Harriet Lane Handbook, 23rd ed.

Relative Potency Comparison

• Katzung's Basic and Clinical Pharmacology, 16th ed., Table 39-1
• Washington Manual of Medical Therapeutics

Adverse Effects

• Skin atrophy, striae, telangiectasia (with prolonged use or occlusion)
• Hypopigmentation, contact dermatitis (to the steroid molecule or vehicle)
• Perioral dermatitis, acneiform eruption on face
• Suppression of HPA axis with extensive use (especially in children)

• Metabolic: Hyperglycemia, dyslipidemia, central obesity (Cushingoid features), osteoporosis
• Endocrine: HPA axis suppression, growth retardation in children
• Cardiovascular: Hypertension (via mineralocorticoid effect - hydrocortisone has the highest salt-retaining potency of common glucocorticoids)
• GI: Peptic ulceration (possibly via suppressed local immunity to H. pylori)
• Neuropsychiatric: Insomnia, euphoria, depression, pseudotumor cerebri
• Hematologic: Leukocytosis, thrombocytosis, erythrocytosis
• Immunologic: Increased susceptibility to infections (especially chickenpox/measles - caution in immunocompromised patients)
• Epigenetic effects: In prenatal/early pediatric exposure, may cause long-term epigenetic changes predisposing to metabolic syndrome or behavioral disorders
• Katzung's Basic and Clinical Pharmacology, 16th ed., pp. 1105-1106
• Harriet Lane Handbook, 23rd ed.

Contraindications & Cautions

• Untreated systemic fungal infections (systemic use)
• Active viral skin infections (herpes simplex, varicella) - topical use
• Avoid topical use on face for high-potency agents (hydrocortisone acetate 1% is generally acceptable on face due to low potency)
• Hypertrophic cardiomyopathy has been reported in premature infants with systemic corticosteroid use
• Immunocompromised patients: avoid exposure to chickenpox and measles

Key Clinical Pearls

1. Hydrocortisone acetate is the mildest topical corticosteroid (Group 1/lowest potency class) - appropriate for sensitive areas (face, skin folds, infants)
2. The acetate ester slows local release from depot (intra-articular) sites - hence preferred over the sodium phosphate or succinate salts for joint injection
3. It has mineralocorticoid activity (unlike dexamethasone or methylprednisolone) - relevant in conditions requiring pure glucocorticoid replacement (e.g., congenital adrenal hyperplasia workup)
4. Lab interference: hydrocortisone acetate cross-reacts in cortisol immunoassays - a clinically important consideration during adrenal testing
5. For CAH and adrenal insufficiency, modified-release hydrocortisone formulations (mimicking physiologic circadian cortisol secretion) are now available and preferred over conventional tablets to minimize adverse metabolic effects

• Harrison's Principles of Internal Medicine, 22nd ed.