interpatient

Interpatient is an adjective describing phenomena that occur between patients or differences that exist among different patients. It is used primarily in medicine and healthcare to distinguish between phenomena observed across multiple individuals and those that occur within a single patient (intrapatient).

Common contexts include interpatient variability, such as differences in drug absorption, distribution, metabolism, and excretion among patients, which can affect the efficacy and safety of therapies. Causes of interpatient variability include genetic polymorphisms (pharmacogenomics), age, body weight, organ function (liver and kidney), comorbidities, concomitant medications, and environmental factors.

In pharmacokinetics and pharmacodynamics, interpatient variability can lead to wide ranges of plasma drug concentrations at a given dose. To manage this variability, clinicians and researchers use approaches such as population pharmacokinetic modeling, therapeutic drug monitoring, dose individualization, and pharmacogenetic testing.

In infection control and epidemiology, interpatient transmission describes the spread of pathogens from one patient to another, a concern in hospitals and long-term care facilities that can contribute to nosocomial infections. Mitigation strategies include infection prevention measures, isolation precautions, hand hygiene, and antimicrobial stewardship.

Related terms include intrapatient (within a single patient), interindividual, and interspecies. In research, distinguishing interpatient from intrapatient effects helps in study design and interpretation. The term is widely used across clinical research, pharmacology, and healthcare settings to emphasize differences or interactions between distinct patients rather than within a single patient. It is a general descriptive construct in medical science rather than tied to a specific disease or condition.