Budesonide Inhaled

Budesonide is an inhaled corticosteroid with high first-pass hepatic metabolism, giving relatively low systemic exposure. It is used for asthma, in combination with formoterol for maintenance and reliever therapy, in COPD combinations, and by nebuliser in children.

Classification. Inhaled corticosteroid, glucocorticoid.

Mechanism. Glucocorticoid receptor agonist suppressing airway inflammation. Reversible fatty-acid esterification in the airway prolongs lung retention.

Pharmacokinetics. Systemic bioavailability of the swallowed fraction is about 10%. Half-life 2 to 3 hours. Metabolised by CYP3A4, so strong inhibitors increase systemic exposure.

First-line, persistent asthma, adults. Low 200 to 400 micrograms daily, medium over 400 to 800 micrograms daily, high over 800 micrograms daily. Usual start 200 to 400 micrograms twice daily; maximum 800 micrograms twice daily under specialist direction.

First-line, asthma maintenance and reliever therapy. Budesonide with formoterol 160/4.5 micrograms (delivered): 1 to 2 inhalations twice daily plus 1 inhalation as needed. Maximum 12 inhalations in 24 hours.

First-line, mild asthma. Budesonide with formoterol 1 inhalation as needed, with no regular maintenance.

Children from 6 years. 100 to 200 micrograms twice daily, adjusted to the lowest effective dose. Higher doses only under specialist direction.

Nebulised, children from 6 months. 250 to 500 micrograms twice daily, up to 1 mg twice daily in severe persistent asthma under specialist direction.

Alternative, croup. Nebulised 2 mg as a single dose when an oral corticosteroid is not tolerated. Dexamethasone 0.15 mg/kg orally is the usual choice.

COPD. Budesonide with formoterol, or triple therapy, in patients with frequent exacerbations and blood eosinophils of 300 cells/microlitre or more.

Emergency. Not used. Systemic corticosteroid is needed.

Titration. Step down about 25 to 50% every 3 months when control holds. No loading dose.

Contraindications. Hypersensitivity. Caution in active or quiescent pulmonary tuberculosis.

Serious adverse effects. Adrenal suppression, reduced growth velocity, cataract, glaucoma, reduced bone density, pneumonia in COPD, paradoxical bronchospasm. Iatrogenic Cushing syndrome has occurred with ritonavir or cobicistat.

Common adverse effects. Oral candidiasis, hoarseness, cough, bruising.

Interactions. Ritonavir, cobicistat, itraconazole, ketoconazole and clarithromycin raise budesonide exposure; avoid or use an ICS less dependent on CYP3A4.

Common prescribing errors. Giving a maintenance and reliever regimen with a separate maintenance combination product. Mixing delivered and metered strengths. Prescribing alongside ritonavir.

Special groups.

• Pregnancy: the ICS with the most reassuring data; continue. Breastfeeding: compatible.

• Children: monitor height annually.

• Older adults: monitor bone health and eyes on high doses.

• Kidney impairment: no adjustment. Liver impairment: exposure increases in severe disease; monitor for corticosteroid effects.

• East Africa: where ritonavir-boosted antiretroviral therapy is used, prefer beclometasone.

Formulations. Inhaler 100 and 200 micrograms/actuation; dry powder 100, 200 and 400 micrograms/dose; nebuliser suspension 0.25 mg/mL and 0.5 mg/mL; fixed combinations with formoterol.

Technique. Rinse the mouth and spit after each dose. Use a spacer with inhalers. Nebulise with a mouthpiece or a tight-fitting mask and wipe the face afterwards.

Baseline. Spirometry or peak flow, control score, height in children.

Monitoring. Control, reliever use, exacerbations, spirometry at 3 to 6 months, technique, height, adrenal and bone effects on prolonged high doses.

Stop and reduce rules. Step down when control holds for 3 months. Therapeutic drug monitoring is not used.

Referral and escalation. Refer when control fails on high-dose ICS with a LABA.