Drug-Drug Interactions

When a drug is taken together with a second drug, drug-drug interaction may occur, thereby increasing or decreasing the effects of one or both drugs. Drug-drug interaction (DDI) is the most common type of drug interaction. It is defined as the change in efficacy or toxicity of a drug after the use of the second drug. DDI may delay, decrease or enhance drug absorption, increase minor or serious unexpected side effects, or even increase the possible toxicity of a certain drug. Drug-drug interaction may be a pharmacodynamic interaction or a pharmacokinetic interaction.

Pharmacodynamic drug interaction often occurs when two drugs compete with the same or similar target molecules. Two drugs with similar pharmacological effects may lead to an additive or synergistic effect and such situations can be exploited to improve therapeutic outcome. Pharmacodynamic drug interaction also may lead to a decreased or blocking effect. On the other hand, if the additive or synergistic interaction is associated with adverse or toxic effects, the possibility of organ damage or other serious consequences may be greatly increased. These types of interactions are usually caused by overlapping side effects. Pharmacokinetic interaction is more common and often occurs when a drug’s absorption, distribution, metabolism, or excretion is affected by another drug. Pharmacokinetic interaction alters magnitude and duration of the effects rather than the type. It is predictable based on the knowledge of individual drugs or by monitoring drug concentrations or clinical signs.

Assessing drug–drug interaction potential for new chemical entities at stages in drug development. Figure 1. Assessing drug–drug interaction potential for new chemical entities at stages in drug development. (Wienkers, L. C., et al., 2005)

Creative Biolabs provides a wide range of drug-drug interaction assays for safety assessment of drug research and development thus to deal with data reproducibility crisis which is a big obstacle for drug research and development and may lead to failure and high risk of investment. With our comprehensive assays, we can drive forward and speed up your drug discovery and development process.

Adverse DDI has become a crucial issue because it can put patients at risk of side effects and toxicity. Therefore, checking for drug interaction is important for each new drug. Creative Biolabs has established a full portfolio of assay systems to provide our customers overall information concerning the DDI potential of investigated compounds. Our services include but not limited to the following:

Drug Metabolism Services

Drug metabolism refers to the biotransformation of drugs within the body. The purpose of metabolism is to change the structure of the substance so that they can be excreted from the body more easily. Most drug metabolism occurs in the liver, as the enzymes that facilitate the reactions are concentrated there. Some drug metabolism occurs in the gut wall, lungs, or blood plasma. The most common type of metabolic drug-drug interaction is the inhibition and induction of drug metabolic enzymes, such as CYP450 and UGT. With experienced staff and professional platforms, we provide metabolism services to help clients accelerate the process of drug discovery and development.

Drug Transporter Services

Transporters are large proteins located in the plasma membrane of cells. Drug transporters mediate the cellular uptake and efflux of a broad variety of drugs and drug metabolites. Except for key metabolic enzymes, induction or inhibition of drug transporters is another important mechanism underlying DDI. Transporter-mediated drug–drug interactions in small intestine, liver and kidney can considerably influence the pharmacokinetics and clinical effects of drugs. With decades of experience in preclinical drug studies, we provide a broad range of services about transporter-mediated DDI to evaluate pharmacological and toxicological effects of your drug candidates.

Creative Biolabs has a dedicated assay development team that will work closely with you to design customized assays. Our service will meet your specific needs fast at extremely competitive prices. If you need more information, please feel free to contact us at anytime. We look forward to working with you to help your drug research and development project succeed.


  1. Wienkers, L. C.; Heath, T. G., 2005. Predicting in vivo drug interactions from in vitro drug discovery data. Nature reviews Drug discovery, 4(10), pp. 825-833.
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