Selectivity pharmacodynamic agents

For pharmacodynamic agents acting within one species (human), selectivity may also be achieved by differences in accumulation, when similar receptors are located in cells or in membranes of different character. The neurotransmitter receptors, for example, are similar, but are found in a variety of highly differentiated cells whose membranes are unlikely to possess the same physical characteristics. 

Comparison of the relative activity of various quinolones can be accomplished by comparing pharmacodynamic parameters against key pathogens using population pharmacokinetic data and published or institutional susceptibility data. Evaluation of such data can assist in the selection of agents for formulary consideration. 

Nebivolol is a new selective adrenergic blocking agent that possesses a unique pharmacodynamic profile, by which it differs from traditional P -blockers. 

The recovering patient who remains depressed after appropriate treatment of the abstinence syndrome should be given an antidepressant trial. Treatment planning should take into account the patient s physical status, especially because it may affect the pharmacokinetics and pharmacodynamics of the agent selected (see Chapter 3). 

Artemisinin compounds clear parasites from the blood more rapidly than any other antimalarial agent, by a unique pharmacodynamic action. They are concentrated in parasitized erythrocytes, and structure-activity relations (see Chapter 2) suggest that their endoperoxide bridge is essential for the antimalarial effect. A critical step in the mechanism of action seems to be a hemin-catalyzed reduction of the peroxide moiety, which results in free radicals and reactive aldehydes that subsequently kill the malaria parasites. The hemin-rich internal environment of the parasites is assumed to be responsible for the selective toxicity of artemisinin toward these organisms. 

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