Corticosteroids
Glucocorticoids are endogenous (hydrocortisone) and synthetic (prednisolone, methylprednisolone, dexamethasone) steroid hormones with metabolic, anti-inflammatory, and immunosuppressive effects. They bind to specific intracellular receptors and translocate into the nucleus, where they regulate gene expression in a tissue-specific manner.
Corticosteroids have multiple indications including:
- Replacement in adrenal suppression or other cortisol-deficient states
- Autoimmune disorders
- Anaphylaxis and atopic disorders, including asthma
- Hypercalcaemia
- Chemotherapy
- Immunosuppression following transplantation
Common Features
| System | Effect |
|---|---|
| Resp | ↑ Bronchial smooth muscle response to circulating catecholamines, ↓ airway oedema |
| CVS | ↑ Inotropy, ↑ vascular smooth muscle response to circulating catecholamines (↑ receptor expression), ↑ BP secondary to mineralocorticoid effects |
| CNS | Mood changes, sleep disturbance, psychosis |
| MSK | Atrophy, thinning of skin |
| Renal | Glycosuria, Na+ and fluid retention (mineralocorticoid effect), hypokalaemia |
| GIT | Gastric ulceration |
| Metabolic | ↑ Gluconeogenesis, diabetes, ↑ protein catabolism, fat redistribution, adrenal suppression (negative feedback on ACTH), ↑ lipolytic response to circulating catecholamines |
| Immune | ↓ Transudate production, ↓ production of inflammatory mediators, ↓ macrophage function, ↓ transport of lymphocytes, ↓ T-cell function, ↓ antibody production, ↑ susceptibility to infection, |
| Toxic Effects | Relative steroid deficiency in adrenal suppressed individuals with infection or surgery |
Comparison of Corticosteroids
| Property | Hydrocortisone | Prednisolone | Methylprednisolone | Dexamethasone |
|---|---|---|---|---|
| Route of Administration | IV/PO | PO | PO/IV/IM | IV |
| Relative Dose Equivalents | 100mg | 25mg | 20mg | 4mg |
| Absorption | 50% PO bioavailability | 100% PO bioavailability | 60% PO bioavailability | |
| Distribution | Variable protein binding depending on concentration, VD 0.5 L.kg-1 | Variable protein binding depending on concentration, VD 0.5 L.kg-1 | VD 1 L.kg-1 | |
| Metabolism | Hepatic | Hepatic | Hepatic | Hepatic |
| Elimination | Elimination t0.5 is 2 hours | Elimination t0.5 is 3 hours | Elimination t0.5 is 3 hours | Elimination t0.5 is 4 hours |
| Relative mineralocorticoid effect | +++ | ++ | + | + |
References
- Peck TE, Hill SA. Pharmacology for Anaesthesia and Intensive Care. 4th Ed. Cambridge University Press. 2014.
- Smith S, Scarth E, Sasada M. Drugs in Anaesthesia and Intensive Care. 4th Ed. Oxford University Press. 2011.
- Nieman LK, Lacroix A, Martin KA. Pharmacologic use of glucocorticoids. In: UpToDate, Post, TW (Ed), UpToDate, Waltham, MA, 2017.
- Petkov V. Essential Pharmacology For The ANZCA Primary Examination. Vesselin Petkov. 2012.