Drug interactions
Dexamethasone + Isoniazid
Severity: Minor
Dexamethasone and Isoniazid: minor interaction.
Last updated
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
Isoniazid may slightly reduce dexamethasone clearance through CYP3A4 inhibition, which would increase corticosteroid effects. Corticosteroids may in turn alter isoniazid acetylation and the combination may raise glucose. The clinical effect is generally small.
What this interaction means in plain words
Dexamethasone and Isoniazid have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Dexamethasone belongs to Endocrine; Isoniazid belongs to Anti Bacterial.
Why it happens
Weak CYP3A4 inhibition by isoniazid may decrease dexamethasone metabolism.
What to do
No routine change is needed. Monitor for corticosteroid adverse effects such as hyperglycemia and fluid retention during prolonged use.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Isoniazid
Other interactions of Dexamethasone
- Bcg vaccine live + Dexamethasone Contraindicated
- Dexamethasone + Mifepristone Contraindicated
- Dexamethasone + Rilpivirine Contraindicated
- Dexamethasone + Smallpox vaccine live Contraindicated
- Dexamethasone + Varicella virus vaccine live Contraindicated
- Dexamethasone + Yellow fever vaccine Contraindicated
Frequently asked questions
Can I take Dexamethasone with Isoniazid?
MediHelp rates the interaction as minor. Dexamethasone and Isoniazid have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Isoniazid may slightly reduce dexamethasone clearance through CYP3A4 inhibition, which would increase corticosteroid effects. Corticosteroids may in turn alter isoniazid acetylation and the combination may raise glucose. The clinical effect is generally small.
How serious is the interaction between Dexamethasone and Isoniazid?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No routine change is needed. Monitor for corticosteroid adverse effects such as hyperglycemia and fluid retention during prolonged use.
What other medicines interact with Isoniazid?
MediHelp also lists interactions of Isoniazid with, for example, Bacillus calmette-guerin substrain tice, Benzhydrocodone / acetaminophen, Carbamazepine. The full list is on the Isoniazid page.
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