heart-failure
4 interactions related to heart-failure
metoprolol + coq10
Metoprolol and other beta-blockers have been shown in laboratory studies to inhibit some CoQ10-dependent enzymes, and long-term beta-blocker therapy is associated with modestly lower CoQ10 levels. There is no absorption clash: CoQ10 does not change metoprolol's blood-pressure or heart-rate effects, and metoprolol does not change how the body uses CoQ10. Whether this depletion meaningfully causes fatigue, or whether CoQ10 supplementation relieves it, rests largely on mechanism rather than interaction-specific trials.
metoprolol + hawthorn
Hawthorn (Crataegus) has mild vasodilatory and heart-supporting effects that can add to the blood-pressure and heart-rate lowering of metoprolol, modestly increasing the chance of low blood pressure, a slow pulse, dizziness, or fainting. The interaction is pharmacodynamic (it happens at the receptor and tissue level), not metabolic, so taking the doses at different times does not prevent it.
carvedilol + st. john's wort
Carvedilol is partly broken down by liver enzymes (including CYP2C9 and CYP3A4) and is also a P-glycoprotein substrate. St. John's Wort induces several of these enzymes and P-glycoprotein, which can speed carvedilol clearance and lower its blood levels, potentially weakening its blood-pressure and heart-failure effects. The interaction is mechanism-based and extrapolated from St. John's Wort's effect on similar drugs; no direct human study of this specific pair has been published.
hawthorn + coq10
Hawthorn (Crataegus) flavonoids and oligomeric procyanidins act on the mechanical and vascular side of heart function, while CoQ10 supports the heart's energy metabolism in the electron transport chain. The two are sometimes combined as low-risk cardiovascular adjuncts, but the supportive human evidence is for each ingredient separately, not for the pair, so any "synergy" is extrapolated rather than demonstrated.