Odontologia

Corticoides
Corticosteroids are a class of chemicals that includes steroid hormones naturally produced in the adrenal cortex of vertebrates and analogues of these hormones that are synthesized in laboratories. Corticosteroids are involved in a wide range of physiologicprocesses, including stress response, immune response, and regulationof inflammation, carbohydrate metabolism, proteincatabolism, blood electrolyte levels, and behavior.

▪ Glucocorticoids such as cortisol control carbohydrate, fat and protein metabolism and are anti-inflammatory by preventingphospholipid release, decreasing eosinophil action and a number of other mechanisms.
▪ Mineralocorticoids such as aldosterone control electrolyte and water levels, mainly by promoting sodium retention in thekidney.
Some commonnatural hormones are corticosterone (C21H30O4), cortisone (C21H28O5, 17-hydroxy-11-dehydrocorticosterone) andaldosterone.


Biosynthesis


[pic]
Corticosteroid biosynthetic pathway in rat
The corticosteroids are synthesized from cholesterol within the adrenal cortex. Most steroidogenic reactions are catalysed by enzymesof the cytochrome P450 family. They are located within the mitochondria andrequire adrenodoxin as a cofactor (except 21-hydroxylaseand 17α-hydroxylase).

Aldosterone and corticosterone share the first part of their biosynthetic pathway. The last part is mediated either by the aldosterone synthase (for aldosterone) or by the 11β-hydroxylase (for corticosterone). These enzymes are nearly identical (they share 11β-hydroxylation and 18-hydroxylation functions), butaldosterone synthase is also able to perform an 18-oxidation. Moreover, aldosterone synthase is found within the zona glomerulosa at the outer edge of the adrenal cortex; 11β-hydroxylase is found in the zona fasciculataand zona glomerulosa.


Classification


By chemical structure

In general, corticosteroids are grouped into four classes, based on chemical structure. Allergic reactions to onemember of a class typically indicate an intolerance of all members of the class. This is known as the "Coopman classification",[1] after S. Coopman, who defined this classification in 1989.[2]

The highlighted steroids are often used in the screening of allergies to topical steroids.[3]


Group A — Hydrocortisone Type

Hydrocortisone, hydrocortisone acetate, cortisone acetate, tixocortolpivalate, prednisolone, methylprednisolone, and prednisone (Short- to medium-acting glucocorticoids).


Group B — Acetonides (and related substances)

Triamcinolone acetonide, triamcinolone alcohol, mometasone, amcinonide, budesonide, desonide, fluocinonide, fluocinolone acetonide, and halcinonide.


Group C — Betamethasone Type

Betamethasone, betamethasone sodiumphosphate, dexamethasone, dexamethasone sodium phosphate, and fluocortolone.


Group D — Esters


Group D1 — Halogenated (Less Labile)

hydrocortisone-17-valerate, aclometasone dipropionate, betamethasone valerate, betamethasone dipropionate, prednicarbate, clobetasone-17-butyrate, clobetasol-17-propionate,fluocortolone caproate, fluocortolone pivalate, and fluprednidene acetate.


Group D2 — Labile Prodrug EstersHydrocortisone-17-butyrate, 17-aceponate, 17-buteprate, and Prednicarbate.


By route of administration


Topical steroids

Main article: Topical steroid
For use topically on the skin, eye, and mucous membranes.

Topical corticosteroids are divided in potency classes I to IV,


[edit]Inhaled steroids

for use to treat the nasal mucosa, sinuses, bronchii, and lungs.[4] Thisgroup includes:

▪ Flunisolide[5]
▪ Fluticasone propionate[5]
▪ Triamcinolone acetonide[5]
▪ Beclomethasone dipropionate[5]
▪ Budesonide[5]
There is also a combination preparation (trade name Advair), containing fluticasone propionate and salmeterol xinafoate (a long-acting bronchodilator).[5] It is approved for children over 12 years old.


Oral forms

Such as prednisone and...