Metolazone and Terazosin interaction

Metolazone and Terazosin: 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.

Drug interactionsby drug classView label on DailyMed

From the Terazosin (TEZRULY) label · effective 2025-04-18

Moderate

Risk of Hypotension with Concomitant Use of Other Antihypertensive Agents and Phospodiesterase Type 5 Inhibitors (PDE5-I): Concomitant administration of TEZRULY with antihypertensives or phosphodiesterase-5 (PDE-5) inhibitors can result in additive blood pressure lowering effects and symptomatic hypotension (5.3).

Warnings and precautionsby drug classView label on DailyMed
Moderate

Syncope has also been reported with other alpha-1-adrenoceptors antagonists in association with rapid dosage increases or the introduction of another antihypertensive drug.

Warnings and precautionsby drug classView label on DailyMed
Moderate

Then slowly increase the dose [see Dosage and Administration (2.1 and 2.2)] , and add additional antihypertensive agents with caution.

Warnings and precautionsby drug classView label on DailyMed
Moderate

Risk of Hypotension with Concomitant Use of Other Antihypertensive Agents and Phosphodiesterase Type 5 Inhibitors (PDE5-I) Concomitant use of TEZRULY with other anti-hypertensive agents, especially the calcium channel blocker verapamil, can increase the risk of hypotension.

Warnings and precautionsby drug classView label on DailyMed

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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.