beta-blocker
9 interactions related to beta-blocker
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.
propranolol + melatonin
Propranolol blocks the beta-adrenergic signal the pineal gland uses to make melatonin at night, lowering the body's own nighttime melatonin.
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.
atenolol + calcium
Calcium supplements and calcium-based antacids taken at the same time as atenolol bind it in the gut and reduce how much of the drug is absorbed, blunting its blood-pressure and heart-rate effects. Separating the two doses by several hours preserves atenolol's effect. Calcium from ordinary meals is generally not a concern.
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.
metoprolol + melatonin
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.
propranolol + st. john's wort
St. John's Wort induces several liver drug-metabolizing enzymes, including CYP1A2 and CYP3A4, plus the transporter P-glycoprotein. Propranolol is cleared mainly through CYP1A2 and CYP2D6, so regular St. John's Wort use can plausibly speed up its breakdown and weaken its effect. Direct studies of this specific pair are lacking; the concern is based on St. John's Wort's confirmed enzyme-inducing action, its documented lowering of theophylline (which shares propranolol's CYP1A2 pathway), and a case report of lost intraocular-pressure control in a glaucoma patient on a topical beta-blocker.
smoking + propranolol
Cigarette smoking induces hepatic metabolism of propranolol (mainly via CYP1A2 and glucuronidation), increasing its clearance and lowering propranolol blood levels in smokers compared with non-smokers. Nicotine also independently raises heart rate, blood pressure, and circulating catecholamines, partly counteracting propranolol's beta-blocking effect. Both effects reverse when a person quits smoking.
black pepper + propranolol
Piperine, the active alkaloid in black pepper, can inhibit intestinal P-glycoprotein and several liver enzymes that normally limit how much propranolol reaches the bloodstream. A small human study found that concentrated piperine raised propranolol's blood levels, so a stable dose may behave like a somewhat higher one, slightly amplifying its blood-pressure and heart-rate effects. Culinary pepper is not the concern; concentrated piperine supplements are.