Pharmacokinetics of Caffeine: A Systematic Analysis of Reported Data for Application in Metabolic Phenotyping and Liver Function Testing.
Level 1 - systematic review of randomized trials
Systematic review/synthesis of published pharmacokinetic studies
PubMed 35280254 · doi:10.3389/fphar.2021.752826
What was done
The authors performed an integrative systematic analysis of human pharmacokinetic data from 141 published studies evaluating caffeine, its metabolites (paraxanthine, theobromine, and theophylline), and metabolic ratios. They compiled participant metadata (age, weight, smoking status, health status), intervention specifics (dosing, substance, route), time-courses, and pharmacokinetic parameters (clearance, half-life, area under the curve). The curated dataset was used to evaluate the effects of smoking, oral contraceptives, drug-drug interactions, disease states, and the correlation between plasma and saliva caffeine measurements.
What was found
The abstract reports the curation of a comprehensive pharmacokinetic dataset across 141 publications and demonstrates its utility in assessing confounding factors (smoking, oral contraceptives, drug interactions, disease) and the validity of salivary testing. However, the abstract provides no specific numerical values, effect sizes, statistical metrics, or directional summary statistics.
Why it matters
Synthesizing published pharmacokinetic data helps clarify sources of inter-individual variability in caffeine clearance, supporting more accurate applications in CYP1A2 metabolic phenotyping and clinical liver function testing.
Limits
The abstract reports zero quantitative findings or effect estimates. Aggregating published data across 141 distinct studies introduces substantial heterogeneity in study designs, analytical assays, patient populations, and dosing protocols.
Cited by
- supports Caffeine has an elimination half-life of approximately 6 to 7 hours and a quarter-life of about 12 hours in humans.