Guide to Good Prescribing - A Practical Manual
(1994; 115 pages) [French] [Spanish] View the PDF document
Table of Contents
View the documentAcknowledgments
View the documentWhy you need this book
Open this folder and view contentsPart 1: Overview
Open this folder and view contentsPart 2: Selecting your P(ersonal) drugs
Open this folder and view contentsPart 3: Treating your patients
Open this folder and view contentsPart 4: Keeping up-to-date
Close this folderAnnexes
Close this folderAnnex 1: Essentials of pharmacology in daily practice
View the documentIntroduction
Close this folderPharmacodynamics
View the documentThe Cp/response curve
Open this folder and view contentsPharmacokinetics
Open this folder and view contentsDrug treatment
Open this folder and view contentsSpecial features of the curve
View the documentAnnex 2: Essential references
Open this folder and view contentsAnnex 3: How to explain the use of some dosage forms
Open this folder and view contentsAnnex 4. The use of injections
View the documentBack Cover
 
The Cp/response curve

The shape of the Cp/response curve is determined by pharmacodynamic factors. Cp/response curves reflect the result in a number of individuals, referred to as a ‘population’. If the plasma concentration is lower than where the curve begins, 0% of the population will experience an effect. An effect of 50% means that the average effect in the total population is 50% of the maximum (and not a 50% effect in one individual) (Figure 10).

Unfortunately, most drugs have a Cp/response curve for side effects as well. This curve should be interpreted in the same way as Cp/response curves. The two curves together define the minimum and maximum plasma concentrations. The concentration that gives the minimum useful effect is the therapeutic threshold, while the plasma concentration at which the maximum tolerated side effects occur is called the therapeutic ceiling. Remember that Cp/response curves represent the dynamics in a group of patients, and can only offer a guideline when thinking in terms of an individual patient.

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