Psychotropic drugs pharmacokinetics

DNLM 1. Mental Disorders—drug therapy—United States. 2. Asian Americans—United States. 3. Blacks—United States. 4. Ethnic Groups— United States. 5. Hispanic Americans—United States. 6. Mental Disorders— ethnology—United States. 7. Psychotropic Drugs—pharmacokinetics— United States. WM 402 E84 2000]... 

David Taylor is Chief Pharmacist at the South London and Maudsley NHS Trust. Honorary Senior Lecturer at the Institute of Psychiatry and Foundation President of the College of Mental Health Pharmacists. His main areas of research are pharmacokinetics and prescribing practice in mental health. His team at the Maudsley is widely involved in systemic reviews and meta-analyses of psychotropic drug therapy. David is lead author of the Maudsley 2001 Prescribing Guidelines (Martin Dunitz, 2001) and co-editor of Case Studies in Psychopharmacology (Martin Dunitz, 1998). 

Ethnic differences in psychotropic drug response and pharmacokinetics... 

Hopefully these few examples will serve to emphasize the importance of a knowledge of the pharmacokinetic features of psychotropic drugs in order to avoid the potentially serious side effects that can result from drug interactions. 

In SUMMARY, it would appear that a detailed knowledge of the pharmacokinetics of the main groups of psychotropic drugs is only of very limited clinical use. This is due to limitations in the methods for the detection of some drugs (e.g. the neuroleptics), the presence of active metabolites which make an important contribution to the therapeutic effect, particularly after chronic administration (e.g. many antidepressants, neuroleptics and anxiolytics), and the lack of a direct correlation between the plasma concentration of the drug and its therapeutic effect. Perhaps the only real advances will be made in this area with the development of brain imaging techniques whereby the concentrations of the active drug in the... 

Despite the limited value of measuring plasma psychotropic drug concentrations to assess clinical response, a knowledge of the pharmacokinetics of such a drug can be of value in predicting drug interactions. 

The decision to use a psychotropic drug must take into account the potential risks and benefits. This should be discussed with the patient and/ or carer. Before prescribing, a full evaluation of the symptoms should be made and the diagnosis confirmed. Polypharmacy should be avoided. If a drug combination is necessary, the pharmacod)mamic and pharmacokinetic interactions should be considered. 

Yoshida, K., Smith, B., et al. (1999) Psychotropic drugs in mothers milk a comprehensive review of assay methods, pharmacokinetics and of safety of breast-feeding. / Psychopharmacol 13 64-80. 

Figure 5.1 Pharmacokinetics and pharmacodynamics of the psychotropic drugs in the body. Pharmacokinetic routes of absorption, cSstribution, metabolism and excretion are represented by single lines. Pharmacodynamic effects such as biological and neurobio logical effects, receptoi binding, modulation of signal transudation, etc. are represented by double-dotted lines...

The cost of generic substitutes is usually considerably less than that for the trade name psychotropic drugs, but issues of bioequivalence must also be considered (see the section The Four Primary Pharmacokinetic Phases in Chapter 3). Using the fewest tablets to achieve a targeted dose level is always less expensive. Unit dose systems, sustained release preparations, and concentrate forms all increase the cost ( 26). 

Weller R, Preskorn SH. Psychotropic drugs and alcohol pharmacokinetic and pharmacodynamic interactions. Psychosomatics 1984 25 301-309. 

Alldredge BK. Seizure risk associated with psychotropic drugs clinical and pharmacokinetic considerations. Neurology 1999 53 S68-S75. 

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