Drug interactions
Budesonide + Nirmatrelvir / ritonavir
Severity: Major
Budesonide and Nirmatrelvir / ritonavir: major interaction.
Last updated Sources: US FDA label
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
The ritonavir component is a strong CYP3A4 inhibitor and markedly increases budesonide exposure. Iatrogenic Cushing syndrome and adrenal suppression have been reported with ritonavir-boosted regimens and CYP3A4-metabolised corticosteroids.
What this interaction means in plain words
Budesonide and Nirmatrelvir / ritonavir can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
Ritonavir potently inhibits CYP3A4 (and P-glycoprotein), greatly reducing budesonide clearance.
What to do
Avoid prolonged coadministration and switch to beclomethasone or prednisolone when long-term corticosteroid is needed; for short courses monitor for hypercortisolism.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Budesonide
Frequently asked questions
Can I take Budesonide with Nirmatrelvir / ritonavir?
MediHelp rates the interaction as major. Budesonide and Nirmatrelvir / ritonavir can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. The ritonavir component is a strong CYP3A4 inhibitor and markedly increases budesonide exposure. Iatrogenic Cushing syndrome and adrenal suppression have been reported with ritonavir-boosted regimens and CYP3A4-metabolised corticosteroids.
How serious is the interaction between Budesonide and Nirmatrelvir / ritonavir?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid prolonged coadministration and switch to beclomethasone or prednisolone when long-term corticosteroid is needed; for short courses monitor for hypercortisolism.
What other medicines interact with Budesonide?
MediHelp also lists interactions of Budesonide with, for example, Aldesleukin, Atazanavir, Bcg vaccine live. The full list is on the Budesonide page.
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