Classifying drug–drug interactions mechanistically gives major insights into Such interactions can be classified mechanistically in an analogous fashion to. Am J Ther. Jun;2(6) Drug Interactions: Classification and Systematic Approach. Freedman MD(1). Author information: (1)Johns Hopkins. Home > June - Volume 2 - Issue 6 > DRUG INTERACTIONS: CLASSIFICATION AND SYSTEMATIC APPROACH. < Previous Abstract. Email to a.
Interaction Classification Drug
First, there are interactions to which all are equally susceptible. In such cases small studies should suffice. For example, induction of CYP3A4 will reduce the effects of drugs that are metabolized by that isozyme. Of course the degree of susceptibility will vary from individual to individual, but the overall susceptibility is such that one would expect to be able to detect such an interaction in a small study of unselected subjects.
Elsewhere, Park et al. Then there are interactions that affect only a subset of individuals. For example, quinidine inhibits the metabolism of dextromethorphan, but only in extensive metabolizers of CYP2D6, not poor metabolizers [ 2 ]. Of course, extensive metabolizers so outnumber poor metabolizers in the population that this type of interaction is detectable in small studies of unselected subjects.
However, the fewer people an interaction affects the more difficult it will be to show it in a small study. How then, short of doing much larger studies, should we design interaction studies when there may be variable susceptibility? One way is to compare drugs. In this issue of the Journal pp. This supports the view that the mechanism of the gemfibrozil interaction is inhibition of CYP2C8.
It does not completely reassure us that the other fibrates do not also interact by a different mechanism in a small subset of the population, but that seems unlikely. Another method is to do a formal study in the individuals in whom the interaction has been anecdotally observed or who have the suspected susceptibility; unfortunately, that is rarely if ever done. The usual method is to study a group of volunteers after observing a patient. For example, anecdotes attest to the fact that some antibiotics reduce the effect of oral contraceptives; however, this interaction has not been demonstrated in small formal studies [ 3 ].
Similarly, small studies of the interaction of paracetamol with coumarin anticoagulants have not shown an effect. In such instances a case-control study may be the only way to elucidate such an interaction [ 4 ], although perhaps pharmacogenomics will eventually contribute too. In this issue of the Journal Dieterle et al. This is reassuring, but they studied only 15 subjects and single-dose administration of warfarin, and we cannot be sure that aliskiren does not affect warfarin in a small subset of the population.
Finally, we lack systematic reviews of reports of interactions, which might give clues to the nature of individual susceptibility. We should be using different types of studies to elucidate different types of drug interactions. We generally think of drug—disease interactions as occurring when a disease alters the pharmacokinetics or pharmacodynamics of a drug.
Such interactions can be classified mechanistically in an analogous fashion to drug—drug interactions. However, consider an interaction in which the drug alters the nature of the disease: It has been said that the more rigorously a country controls infections and the supply and use of antimicrobial drugs, the lower the rate of resistant strains [ 5 ]. However, good evidence is scarce. Are you sure you want to Yes No. Embeds 0 No embeds.
No notes for slide. Drug interactions their types, examples and role 1. Such changes can lead to changes in drug plasma concentrations and ultimately increase the risk of side effects or diminish the efficacy of one or more drugs. Pharmacokinetic interactions are more complicated and difficult to predict because the interacting drugs often have unrelated actions. This can alter the way one or both of the drugs act in the body, or cause unexpected side effects.
Drug-condition interactions occur when a drug worsens or exacerbates an existing medical condition 2. ASHP guidelines on pharmacist-conducted patient education and counseling. You just clipped your first slide! Clipping is a handy way to collect important slides you want to go back to later. Now customize the name of a clipboard to store your clips.
Classifying drug interactions
These classification systems were developed during a time when little was known about the mechanisms of drug interactions and even less. A drug interaction is when two or more drugs interact when administered together . Drug . that it is almost impossible to offer a clear classification for these concepts. It is even likely that many authors would misapply any given classification. classification of drug interactions by Peter P. Lamy. “This is the age of safe surgery and dangerous medicine”, declared the British Medical Journal recently.