Expert: Dr.Paul Skett - 11/15/2005

Question
Essay Title = Discuss the importance of drug metabolism in limiting the pharmacodynamic effects of drugs and its involvement in producing side-effects. Refer to named examples of drugs in your answer.

Hello my name is Neil I have started this essay set for me, however I am worried that I am straying off the point as i have mentioned drug drug interactions? I was wondering if you could give me a few hints on what areas to consider and if there are any papers or journal websites I could use I am currently using your book on Drug metabolism (are there any other books I should consider) and I am finding it useful. Alternatively I could email my essay to you to see if I am on the right track I understand you are extremely busy and any help you can offer will be much appreciated! Many thanks

Answer
Hi, Neil,

Thanks for your question.

If I was answering this question, I would include the following:

Notice the question says "limiting" and, thus, you need to consider only how drug metabolism REDUCES the therapeutic activity of the drug (no need to consider activation of drugs and prodrugs). Discuss role of phase 1 & 2 in limiting effect of drug - what does each phase do? Make sure you give reasonable, worked examples.

For the second part "producing side effects" then you need to give worked examples of how metabolism of a drug can lead to toxic metabolites or metabolites that give anything other than the desired therapeutic effect - again fully worked metabolic scheme and what the toxic metabolite does and how.

It is important to link the actual metabolic route shown to a decrease in theapeutic effect and/or an increase in toxic effect.

Chapter 6 of my textbook does this in detail but you will probably need to look for a few more recent examples to show in depth research on the subject. This is relatively easily done using MEDLINE or EMBASE searches.

Hope this helps.

Best wishes,

Paul