Hydralazine and Metolazone interaction

Hydralazine and Metolazone: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.

Major

Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.

What the FDA labels say

From the Metolazone label · effective 2026-01-15

Major

Other Antihypertensive Drugs When metolazone tablets, USP, are used with other antihypertensive drugs, particular care must be taken to avoid excessive reduction of blood pressure, especially during initial therapy.

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Moderate

Dosage adjustments of other antihypertensives may be necessary.

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Minor

Other Antihypertensives When metolazone tablets, USP, are used with other antihypertensive drugs, care must be taken, especially during initial therapy.

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From the Hydralazine (hydrALAZINE Hydrochloride) label · effective 2026-08-14

Minor

When other potent parenteral antihypertensive drugs, such as diazoxide, are used in combination with hydralazine, patients should be continuously observed for several hours for any excessive fall in blood pressure.

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Not medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.