Optimal antibiotic dosing. The pharmacokinetic-pharmacodynamic interface
1Rainbow Babies and Children's Hospital, Case Western Reserve University School of Medicine, Cleveland, OH 44106-6010, USA.
Postgraduate Medicine
|August 12, 2009
Summary
Optimizing antimicrobial dosing requires understanding pharmacokinetic (PK) and pharmacodynamic (PD) properties. Tailoring antibiotic regimens based on concentration-dependent or time-dependent killing patterns enhances treatment efficacy for infections.
Area of Science:
- Pharmacology
- Infectious Diseases
- Microbiology
Background:
- Successful treatment of infections necessitates integrating antimicrobial pharmacokinetic (PK) and pharmacodynamic (PD) properties.
- Antimicrobial agents exhibit distinct killing patterns: concentration-dependent, time-dependent, or hybrid.
Purpose of the Study:
- To elucidate the relationship between antibiotic PK/PD properties and their efficacy.
- To highlight the importance of PK/PD parameters in optimizing antimicrobial dosing regimens.
Main Methods:
- Classification of antibiotics based on antimicrobial activity patterns (concentration-dependent, time-dependent, hybrid).
- Identification of key PK/PD parameters correlating with efficacy for different antibiotic classes.
Main Results:
- Concentration-dependent killing antibiotics (e.g., aminoglycosides, fluoroquinolones) correlate with peak concentration to MIC ratio and AUC to MIC ratio.
- Time-dependent killing antibiotics (e.g., beta-lactams) correlate with the percentage of time serum concentrations exceed MIC.
- Hybrid patterns involve duration of exposure and post-antibiotic effects.
Conclusions:
- Understanding specific PK/PD parameters is crucial for effective antimicrobial therapy.
- Optimized dosing regimens based on PK/PD principles can improve treatment outcomes for various infections.
Related Concept Videos
01:24Pharmacokinetic–Pharmacodynamic Relationship: Problems
The empirical approach to drug therapy optimization relies on correlating pharmacological response with administered dosage. Such an approach can be costly, time-consuming, and often yields poor correlation due to variables like formulation factors and drug elimination characteristics. A more precise approach correlates response with plasma drug concentration or the amount of drug in the body, rather than dosage. This is achieved through pharmacokinetic-pharmacodynamic (PK/PD) modeling, which...
01:27Pharmacodynamic Models: Overview
Pharmacodynamic (PD) responses describe the interaction between a drug and its biological target, culminating in a physiological effect. These responses can be classified into different types: continuous variables, such as blood glucose levels; categorical outcomes, like survival rates; and time-to-event metrics, such as disease progression. Understanding and modeling PD responses are critical for optimizing drug efficacy and safety.PD models describe the relationship between drug concentration...
01:01Dosage Regimens: Partial Pharmacokinetic Parameters
It is not uncommon for complete drug pharmacokinetic profiles to remain elusive in pharmacokinetics. This necessitates certain educated assumptions by pharmacokineticists to determine appropriate dosage regimens without comprehensive pharmacokinetic data from animal or human studies. One prevalent assumption is setting the bioavailability factor, denoted as F, to 1 or 100%. This assumption caters to the scenario where a drug doesn't achieve full systemic absorption, resulting in the patient...
01:26Pharmacokinetic–Pharmacodynamic Relationship: Exposure, Response and Effect
The pharmacokinetic-pharmacodynamic (PK-PD) relationship describes the intricate link between drug exposure, efficacy, and toxicity, forming the foundation for optimal dosing regimens. This relationship uses mathematical modeling to characterize drug concentration-effect dynamics, ensuring precise therapeutic outcomes.Exposure represents the pharmacokinetic aspect of the PK-PD relationship, denoting the drug amount that elicits a biological response. It is typically quantified by administered...
01:14Pharmacokinetic–Pharmacodynamic Relationship: Model Components
Pharmacokinetic-pharmacodynamic (PK–PD) modeling is essential in drug development and clinical pharmacology. It provides a quantitative framework to predict drug behavior and response over time. This approach integrates pharmacokinetics (PK), which describes the drug's absorption, distribution, metabolism, and excretion, with pharmacodynamics (PD), which characterizes the drug’s biological effects and mechanisms of action.The disposition kinetics of a drug determine its plasma...
01:25Pharmacokinetics: Drug–Drug Interactions
Drug interactions occur when the pharmacological effect of one drug is altered by another substance, either enhancing or diminishing its activity. The drug whose activity is altered is known as the object drug, and the substance causing the alteration is called the agent drug or the precipitant. The net effects of these interactions are mostly undesirable, leading to decreased effectiveness or increased adverse effects. In rare cases, interactions can be beneficial, such as the enhanced...