Core pharmacology

Class Group

Glucocorticoid

Introduction

Natural
Dose Equivalence 25

Indications Uses

1. as replacement therapy in adrenocortical deficiency states and in the
treatment of
2. allergy and anaphylaxis
3. asthma
4. panoply of autoimmune disorders
5. eczema and contact sensitivity syndromes and
6. in leukaemia chemotherapy regimes and
7. for immunosuppression after organ transplantation

Presentation

10/20mg tablets
White lyophilized power to be mixed in water
Other topical preparations

Main Action

Anti-inflammatory

Mechanism of action

lipid solubile → crosses cell membranes → bind to steroid receptors via “zinc finger” binding site
→ signal trascribed via second messenger → alters gene transcription and the production of proteins

Onset Peak Duration

Dur: 8-36h

Physiological effects

1. Metabolic effects
▪ ↑’s gluconeogensis
▪ ↑ protein catabolism and lipolysis → muscle wasting and thin skin and fat redistribution
(cushingoid)
▪ ↑ bone catabolism → osteoporosis
▪ ↑ glucose release but ↓ absorption from the GIT

2. Anti inflammatory effects
▪ ↓’d phospholipase A2 → ↓ arachidonic acid → ↓ prostaglandins

3. Immunosupression
▪ ↓’d inflammatory mediators
▪ ↓ IL 1-2 → ↓’d lymphocyte prod
▪ altered neutrophil and macrophage function

Adverse Effects Toxicity

▪ Adrenal supression via negative feedback on the HPA
▪ Fluid retention - via weak mineralcorticoid activity
▪ Vascular reactivity - plays a permissive role in the actions of catecholamines on vessels

Inhaled: oral candidiasis (poor technique), dysphonia, minor adrenal suppresion

Absorption

IV
Rapidly given PO or PR
PO BA: 50%

Protein binding

CBG 70%, Alb 20%

Volume of distribution

0.5 L/kg

Metabolism

Liver – Tetrahydrocortisone

Excretion

Urine

Clearance

167-283 ml/min

Half-life

0.5-1.5h

Special Points

100

1

Short

Route And Dose

PO,TOP, IV, IM, IA