TABLE 2 

Drugs that influence caffeine pharmacokinetics

Data according to Soto et al. (1994), Amchin et al. (1999), Schmider et al. (1999), Carrillo and Benitez (2000 and references therein), Granfors et al. (2004), Culm-Merdek et al. (2005), Backman et al. (2006), Cysneiros et al. (2007), Darwish et al. (2008), Dinger et al. (2016), Yamazachi et al. (2017).

Drug ClassNameEffect on Caffeine Half-Life
Oral contraceptivesAllAbout +40%
Quinolone antibioticsAmi- and difloxacin+21%
Ciproflacin+70%
Enoxacin+75%
FleroxacinNo effect
Grepafloxacin+50%
Lomeflaxin+23%
Nalidixic acid+67%
Norfloxacin+35%
OfloxacinNo effect
Pefloxacin+22–47%
Pipemidic acid+59%
RufloxacinNo effect
TemafloxacinNo effect
Tosufloxacin+34%
TrovafloxacinNo effect
Cardiovascular drugsMexiletine (anti-arrhythmic)+30%–50%
Diltiazem (calcium antagonist)+22%
Verapamil (calcium antagonist)+20%
Propafenone (anti-arrhythmic)Increase
Propranolol (beta-blocker)Increase
Triamterene (diuretic)Increase
Warfarin (anticoagulant)Increase
CNS drugsClozapine (antidepressant)Variable, up to +26%
Fluvoxamine (antidepressant)−80%; decreases caffeine half-life by sixfold
Venlafaxine (antidepressant, serotonin-norepinephrine reuptake inhibitor (SNRI)No significant effect
Alprazolam (anti-anxiety)No significant effect
Olanzapine (antipsychotic) (Shirley et al. 2003)Slows clearance, interindividual variability
Tryptamine derivatives (psychoactive)Slows caffeine clearance to various degrees
Armodafinil (wakefulness promoting)No significant effect
Tacrine (cholinesterase inhibitor)Slows slightly clearance
Zolpidem (Hypnotic)No significant effect
Anti-inflammatory drugsIdrocilamideHalf-life increased up to 63 h
RofecoxibDecreased clearance
Antifungal medicationFluconazole+ 25%
IsavuconazoleNo effect
Ketoconazole+ 11%
Terbinafine+ 21%
Proton pump inhibitorsCimetidine−31%
LansoprazoleNo effect
Omeprazole−41%
PantoprazoleNo effect
Ondansetron (anti-vomiting)Slows clearance
Psoralens, anti-psoriasis and anti-eczema drugsMethoxsalen−70%
5-Methoxypsoralen−31%
BronchodilatorsFurafyllineIncreases caffeine half-life up to 10-fold
TheophyllineSlows caffeine clearance, twofold