Kenalog etc. (triamcinolone) is an adrenal corticosteroid with potent anti-inflammatory properties. Corticosteroids are synthetic drugs that closely resemble cortisol, a hormone that is naturally produced by the adrenal glands. Corticosteroids work by decreasing inflammation and reducing the activity of the immune system.
Triamcinolone has a relatively long half life (the amount of time before half of the drug's peak plasma level is eliminated by the body) which makes it suitable for once a day oral dosing, and is somewhat more powerful than prednisone. Other corticosteroids include: cortisone and hydrocortisone (weaker in strength than prednisone); prednisolone (a derivative of prednisone that has been chemically changed for easy passage through the liver); methylprednisolone (stronger than prednisone); and dexamethasone and betamethasone (extremely potent and only used in unusual circumstances). For cats and dogs, triamcinolone is primarily used to treat auto-immune conditions and allergic reactions.