Metoprolol and hydrochlorothiazide and Quinidine interaction
Metoprolol and hydrochlorothiazide and Quinidine: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Metoprolol and hydrochlorothiazide (METOPROLOL TARTRATE AND HYDROCHLOROTHIAZIDE) label · effective 2025-01-22
CYP2D6 inhibitors: Increased metoprolol concentration.
…catecholamine-depleting drugs (e.g., reserpine, monoamine oxidase (MAO) inhibitors) with beta adrenergic blockers may have an additive affect and increase the risk of hypotension or bradycardia CYP2D6 Inhibitors: Drugs that are strong inhibitors of CYP2D6 such as quinidine, fluoxetine, paroxetine, and propafenone were shown to double metoprolol concentrations.
From the Quinidine (Quinidine Gluconate) label · effective 2024-08-27
Drugs that alkalinize the urine ( carbonic-anhydrase inhibitors, sodium bicarbonate, thiazide diuretics ) reduce renal elimination of quinidine.
The effects (if any) of coadministration of other β-blockers on quinidine pharmacokinetics have not been adequately studied.
Non-interactions of quinidine with other drugs: Quinidine has no clinically significant effect on the pharmacokinetics of diltiazem, flecainide, mephenytoin, metoprolol, propafenone, propranolol, quinine, timolol, or tocainide .
Coadministration of propranolol usually does not affect quinidine pharmacokinetics, but in some studies the β-blocker appeared to cause increases in the peak serum levels of quinidine, decreases in quinidine's volume of distribution, and decreases in total quinidine clearance.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot 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.