Metoprolol Interactions

Beta-blockers like metoprolol inhibit CoQ10-dependent mitochondrial enzymes, gradually depleting CoQ10 levels in heart tissue and potentially contributing to fatigue, exercise intolerance, and reduced cardiac energy production. CoQ10 supplementation does not reduce metoprolol's blood pressure or heart rate effects but may offset these mitochondrial side effects.

Hawthorn (Crataegus) has mild vasodilatory and positive inotropic effects that can additively lower blood pressure and slow heart rate when combined with metoprolol, increasing the risk of hypotension, bradycardia, dizziness, or syncope. The interaction is pharmacodynamic, not metabolic, so spacing the doses does not prevent it.

Metoprolol blocks the beta-1 adrenergic receptors that drive pineal melatonin synthesis, suppressing endogenous nighttime melatonin and contributing to insomnia, vivid dreams, and reduced sleep efficiency. Low-dose oral melatonin can restore sleep without interfering with metoprolol's cardiovascular benefits.