Drug interactions
Diflunisal + Methazolamide
Severity: Moderate
Diflunisal and Methazolamide: moderate 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
Salicylates such as diflunisal may reduce renal elimination of carbonic anhydrase inhibitors and the inhibitors can raise salicylate levels and CNS penetration. This may cause toxicity such as lethargy, confusion, tinnitus and metabolic acidosis. Risk is highest with high salicylate doses and renal impairment.
What this interaction means in plain words
Diflunisal and Methazolamide can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Competition for renal tubular secretion and acidosis-induced shift of salicylate into the CNS increase exposure to both drugs.
What to do
Monitor for CNS symptoms, tinnitus and acid-base status, particularly in renal impairment. Consider reducing the dose of either drug or choosing a non-salicylate analgesic.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Diflunisal
- Diflunisal + Ketorolac Contraindicated
- Diflunisal + Ketorolac intranasal Contraindicated
- Acemetacin + Diflunisal Major
- Acetazolamide + Diflunisal Major
- Alteplase + Diflunisal Major
- Amiloride + Diflunisal Major
Frequently asked questions
Can I take Diflunisal with Methazolamide?
MediHelp rates the interaction as moderate. Diflunisal and Methazolamide can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Salicylates such as diflunisal may reduce renal elimination of carbonic anhydrase inhibitors and the inhibitors can raise salicylate levels and CNS penetration. This may cause toxicity such as lethargy, confusion, tinnitus and metabolic acidosis. Risk is highest with high salicylate doses and renal impairment.
How serious is the interaction between Diflunisal and Methazolamide?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for CNS symptoms, tinnitus and acid-base status, particularly in renal impairment. Consider reducing the dose of either drug or choosing a non-salicylate analgesic.
What other medicines interact with Diflunisal?
MediHelp also lists interactions of Diflunisal with, for example, Ketorolac, Ketorolac intranasal, Acemetacin. The full list is on the Diflunisal page.
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