Metoprolol Interactions

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.

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 blocks the beta-1 adrenergic receptors the pineal gland uses to receive its nighttime signal to make melatonin, so it tends to suppress your own melatonin and can contribute to insomnia and vivid dreams. A randomized trial in beta-blocker-treated patients found that low-dose bedtime melatonin improved sleep without interfering with metoprolol's cardiovascular benefits. This is a beneficial, low-concern combination rather than a harmful clash.