Related Experiment Video

Updated: Aug 18, 2026

A Computerized Test Battery to Study Pharmacodynamic Effects on the Central Nervous System of Cholinergic Drugs in Early Phase Drug Development
07:02

A Computerized Test Battery to Study Pharmacodynamic Effects on the Central Nervous System of Cholinergic Drugs in Early Phase Drug Development

Published on: February 11, 2019

Relationship between mirtazapine dose, plasma concentration, response, and side effects in clinical practice

K Grasmäder1, P L Verwohlt, K-U Kühn

  • 1Department of Psychiatry, University of Bonn, Germany. kgrasmae@uni-bonn.de

Pharmacopsychiatry
|May 20, 2005
PubMed
Abstract

Related Concept Videos

Nonlinear Pharmacokinetics: Dependence of Elimination Half-Life and Dose Clearance01:23

Nonlinear Pharmacokinetics: Dependence of Elimination Half-Life and Dose Clearance

The elimination half-life and drug clearance of drugs following nonlinear kinetics can vary with dosage. The Michaelis-Menten parameters and drug concentration influence these factors. As the dose increases, the elimination half-life tends to lengthen, resulting in a reduction in clearance and a disproportionately larger area under the curve. The total clearance can be derived from the Michaelis-Menten equation for drugs following a one-compartment model.
A study on guinea pigs examined the...
Pharmacokinetic–Pharmacodynamic Relationship: Problems01:24

Pharmacokinetic–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...
Pharmacokinetic–Pharmacodynamic Relationship: Dose to Pharmacological Effect01:28

Pharmacokinetic–Pharmacodynamic Relationship: Dose to Pharmacological Effect

A drug’s dosage and pharmacokinetic properties determine how quickly it acts, how intense its effects are, and how long it lasts. Higher doses increase drug concentration at receptor sites, producing a hyperbolic curve when pharmacologic response is plotted against drug dose. Converting this scale to a log-linear format results in a sigmoidal curve, better representing dose–response relationships.For drugs following a one-compartment model, the pharmacologic response is directly proportional to...
Effect of Hepatic Disease on Pharmacokinetics: Dose Adjustments Due to Hepatic Impairment01:08

Effect of Hepatic Disease on Pharmacokinetics: Dose Adjustments Due to Hepatic Impairment

Hepatic impairment, characterized by decreased liver function, does not uniformly mandate adjustments in drug dosage. Whether dosage modifications are necessary depends on various factors related to the drug's metabolism and elimination pathways. If a drug is primarily excreted via the kidneys and bypasses significant hepatic processing, if it undergoes minimal metabolic transformation in the liver, or if it is volatile and primarily expelled through the lungs, dose adjustments may not be...
Dosage Regimen: Multiple Oral Dosage01:25

Dosage Regimen: Multiple Oral Dosage

Understanding how a drug's concentration fluctuates within the body over time is crucial in pharmacokinetics, particularly with multiple oral doses. A graphical representation of multiple oral dosages provides insight into these dynamics. Typical accumulation curves of a drug's concentration in the body reveal a sawtooth pattern, indicating periodic peaks and troughs correlating with each dose administration and the drug's subsequent elimination.The plasma concentration at any time during an...
Pharmacokinetic–Pharmacodynamic Relationship: Intensity of Dose-Effect Relationship01:23

Pharmacokinetic–Pharmacodynamic Relationship: Intensity of Dose-Effect Relationship

Pharmacodynamics explores the relationship between drug concentration and its effect. In a quantal response drug, the duration of action better correlates with drug concentration, while for graded effect drugs, the intensity of response is more relevant. This intensity depends on the dose, drug removal rate, and the region of the concentration–response curve.The concentration–response curve can be divided into three regions. Region 3 (80–100% maximum response) demonstrates that even as drug...