propranolol
9 interactions related to propranolol
propranolol + melatonin
Propranolol blocks pineal beta-1 adrenergic receptors that control endogenous melatonin synthesis, suppressing nighttime melatonin levels by roughly 50% and contributing to insomnia, vivid dreams, and reduced sleep efficiency. Low-dose oral melatonin at bedtime can restore sleep architecture without compromising propranolol's antihypertensive effect.
propranolol + st. john's wort
St. John's Wort potently induces CYP1A2 and CYP2C19 along with CYP3A4 and P-glycoprotein, accelerating the metabolism of propranolol and reducing its plasma levels. Documented cases include loss of intraocular pressure control in glaucoma patients on topical beta-blockers, and the mechanism predicts similar loss of antihypertensive and antiarrhythmic effect with systemic propranolol.
alcohol + propranolol
Alcohol and propranolol can produce additive hypotension, dizziness, and sedation through combined vasodilation and central nervous system depression; propranolol also masks the warning symptoms of low blood sugar and rapid heart rate. Chronic heavy drinking induces hepatic enzymes and can reduce propranolol effectiveness.
caffeine + propranolol
Caffeine raises systemic vascular resistance and heart rate, partially opposing propranolol's blood-pressure and heart-rate lowering effects. High caffeine intake can also worsen tremor and anxiety that propranolol is prescribed to treat.
smoking + propranolol
Cigarette smoking induces hepatic metabolism of propranolol via CYP1A2 and accelerated glucuronidation, increasing apparent oral clearance and reducing propranolol plasma concentrations in smokers compared with non-smokers. Nicotine also independently raises heart rate, blood pressure, and circulating catecholamines, partially counteracting propranolol's beta-blocking effect.
cbd + beta-blockers
CBD inhibits several CYP450 enzymes (notably CYP3A4, CYP2C19, CYP2C9, CYP1A2) and may modestly inhibit CYP2D6. Beta-blockers such as metoprolol, propranolol, and carvedilol are metabolized via CYP2D6 (and CYP1A2 for propranolol), so co-use can raise beta-blocker plasma levels, with additive blood-pressure lowering and bradycardia.
energy drinks + beta-blockers
Energy drinks raise sympathetic tone through caffeine, taurine, and guarana, opposing the heart-rate and blood-pressure lowering effects of beta-blockers like metoprolol, atenolol, propranolol, and bisoprolol. Case reports document refractory arrhythmias and hypertensive episodes in patients on beta-blocker therapy who consumed energy drinks regularly.
coffee + propranolol
Caffeine in coffee acutely raises heart rate and blood pressure, which can counteract the heart-rate and blood-pressure-lowering effects of propranolol, a non-selective beta-blocker. Propranolol may also slow caffeine clearance modestly, increasing caffeine exposure.
black pepper + propranolol
Piperine, the active alkaloid in black pepper, inhibits CYP3A4, CYP2C9, and intestinal P-glycoprotein, increasing the oral bioavailability and serum concentration of propranolol and other beta-blockers, which can amplify blood pressure and heart rate reduction.