It is the C16α hydroxyl, C16α,17α cyclic ketal with butyraldehyde derivative of prednisolone (11β,17α,21-trihydroxypregna-1,4-diene-3,20-dione). Stereoisomerism
Society and culture
Legal status
On 19 May 2022, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) adopted a positive opinion, recommending the granting of a conditional marketing authorization for the medicinal product Kinpeygo, intended for the treatment of primary immunoglobulin A nephropathy. The applicant for this medicinal product is Calliditas Therapeutics AB. Kinpeygo is a hybrid medicine of Entocort which has been authorised in the EU since 2 April 1992. Kinpeygo contains the same active substance as Entocort but has a different formulation and a different indication.
Other symptoms which should be reported immediately include difficulty in breathing, swelling of the face, white patches in the throat, mouth, or nose, irregular menstrual periods, severe acne, and on rare occasions, behavioral changes (mostly affecting children)

Contraindications
Budesonide is contraindicated as a primary treatment of status asthmaticus or other acute episode of asthma where intensive measures are required. It is also contraindicated for patients who have hypersensitivity to budesonide. Interactions
Those taking tablets or capsules orally should avoid grapefruit and grapefruit juice and echinacea. : 160 
Grapefruit juice may double bioavailability of oral budesonide. Echinacea diminishes bioavailability.Also, high-fat meals delay absorption but do not impede absorption. Pharmacology
Budesonide is an agonist of glucocorticoid receptors. Among its effects are:

Controls the rate of protein synthesis. Depresses the migration of polymorphonuclear leukocytes and fibroblasts. Reverses capillary permeability and lysosomal stabilization at the cellular level to prevent or control inflammation. Has a potent glucocorticoid activity and weak mineralocorticoid activity. Pharmacokinetics
Onset of action: Nebulization: 2–8 days; Inhalation: 24 hours; Nasal: 10 hours
Peak effect: Nebulization: 4–6 weeks; Inhalation: 1–2 weeks
Distribution: 2.2-3.9 L/kg
Protein binding: 85% to 90%
Metabolism: Hepatic via CYP3A4 to two metabolites: 16 alpha-hydroxyprednisolone and 6 beta-hydroxybudesonide; minor activity
Budesonide is extensively metabolized in first pass, resulting in a low bioavailability and systemic effects
Bioavailability: Capsule: 9% to 21%; Nebulization: 6%; Inhalation: 6% to 13%
Half-life elimination: 2–3.6 hours
Time to peak: Capsule: 0.5–10 hours (variable in Crohns disease); Nebulization: 10–30 minutes; Inhalation: 1–2 hours; Tablet: 7.4-19.2 hours
Excretion: urine (60%) and feces as metabolites. Chemistry
Budesonide, also known as 11β,21-dihydroxy-16α,17α-(butylidenebis(oxy))pregna-1,4-diene-3,20-dione, is a synthetic pregnane steroid and non-halogenated cyclic ketal corticosteroid.