Pharmacology for Anaesthesia and Intensive Care

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25 Corticosteroids and other hormone preparations

Table 25.1.Anti-inflammatory potential of various steroids.

Relative anti- Equivalent anti-

Drug inflammatory potency inflammatory dose (mg)

Hydrocortisone 1 100

Prednisolone 4 25

Methylprednisolone 5 20

Triamcinolone 5 20

Dexamethasone 25 4

hydrocortisone and cortisone, lesser with prednisolone and least with methylpred-

nisolone and dexamethasone.


Vascular reactivity – glucocorticoids have a ‘permissive action’ on vascular smooth

muscle, allowing them to respond efficiently to circulating catecholamines. There-

fore, glucocorticoid deficiency leads to an ineffective response by vascular smooth

muscle to circulating catecholamines. In sepsis there may be an inappropri-

ately reduced production of cortisol so that higher levels of inotropic support are

required. This may be improved by the administration of intravenous hydrocorti-

sone.

Other ‘permissive actions’ of glucocorticoids include the calorigenic effects of

glucagon and catecholamines, and the lipolytic and bronchodilator effects of cate-

cholamines.

Peri-operative steroid supplementation

The magnitude of the surgical stimuls and the pre-operative dose of steroid need

assessment in order to decide the most appropriate peri-operative supplementation

regimen. Patients taking <10 mg prednisolone (or equivalent) pre-operatively have a

normal hypothalamic-pituitary axis (HPA) and do not require peri-operative supple-

mentation. Those taking >10 mg prednisolone require peri-operative supplementa-

tion in addition to their normal steroid. For minor surgery 25 mg hydrocortisone at

induction is sufficient, for moderate surgery a further 100 mg hydrocortisone should

be added over the first 24 hours post-operatively, which should be prolonged for up

to 72 hours for major surgery. The HPA should be considered to be suppressed for

up to 3 months and maybe longer after stopping steroids.

Drugs used in thyroid disease

Thyroid replacement

Thyroxine (T 4 )

The thyroid gland synthesizes triiodothyronine (T 3 )and thyroxine (T 4 )bycombin-

ing iodine with tyrosine residues present in thyroglobulin. The release of T 3 and T 4 is