heart rate
5 interactions related to heart rate
alcohol + propranolol
Alcohol and propranolol can produce additive drops in blood pressure with dizziness, lightheadedness, and fainting through combined vasodilation and a blunted heart-rate response. Propranolol can also mask the racing-heart and shakiness warning signs of low blood sugar, and alcohol can raise propranolol levels in the body.
caffeine + propranolol
Caffeine is a stimulant that nudges heart rate and blood pressure upward, partially opposing the direction propranolol works in. The effect is usually modest, but heavy or concentrated caffeine can blunt propranolol's benefit and worsen the tremor or anxiety it is often prescribed to control.
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.
coffee + propranolol
Caffeine in coffee acutely raises heart rate and blood pressure, which can partly counteract the heart-rate and blood-pressure-lowering effects of propranolol, a non-selective beta-blocker. Propranolol does not fully block this caffeine pressor response. Older claims that propranolol slows caffeine clearance appear to be wrong: a human study found propranolol slightly speeds caffeine elimination rather than slowing it.
nicotine + adenosine
Nicotine produces sympathomimetic cardiovascular effects (faster heart rate, higher blood pressure, peripheral vasoconstriction) that can complicate the periprocedural setting in which intravenous adenosine is used for supraventricular tachycardia or pharmacologic cardiac stress testing. Direct interference with adenosine itself is mechanistic and largely shown in animal models; the better-documented antagonist that smokers commonly co-ingest is caffeine.