Drug interactions
Chlorothiazide + Furosemide
Severity: Moderate
Chlorothiazide and Furosemide: 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
Combining a loop and a thiazide diuretic produces synergistic diuresis and can cause marked hypokalemia, hyponatremia, hypomagnesemia, dehydration and renal impairment. It may be used intentionally in diuretic resistance.
What this interaction means in plain words
Chlorothiazide and Furosemide 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.
Chlorothiazide belongs to Cardiovascular; Furosemide belongs to Cardiovascular.
Why it happens
Sequential nephron blockade with additive natriuresis and kaliuresis.
What to do
Monitor electrolytes, renal function and weight closely after initiation, and replace potassium and magnesium as required.
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 Furosemide
- Amifostine + Furosemide Major
- Amikacin + Furosemide Major
- Carbenoxolone + Furosemide Major
- Cephaloridine + Furosemide Major
- Cisplatin + Furosemide Major
- Digoxin + Furosemide Major
Other interactions of Chlorothiazide
Frequently asked questions
Can I take Chlorothiazide with Furosemide?
MediHelp rates the interaction as moderate. Chlorothiazide and Furosemide 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. Combining a loop and a thiazide diuretic produces synergistic diuresis and can cause marked hypokalemia, hyponatremia, hypomagnesemia, dehydration and renal impairment. It may be used intentionally in diuretic resistance.
How serious is the interaction between Chlorothiazide and Furosemide?
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 electrolytes, renal function and weight closely after initiation, and replace potassium and magnesium as required.
What other medicines interact with Furosemide?
MediHelp also lists interactions of Furosemide with, for example, Amifostine, Amikacin, Carbenoxolone. The full list is on the Furosemide page.
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