Background Info

Purpose of this webpage

This webpage illustrates the most important drug-drug-interactions in compact form. Our aim is to provide information about the pharmacokinetic variables of drugs with interaction potential. In the following sections you will find a detailled description of the interaction table and how to interprete it.

The three phases of drug metabolization

For example, when a drug enters the body, at the first step it is metabolized by the cytochrome P-450 which occur in the liver, but also in the duodenum. This is why this initial process is called Phase-I-oxidation.

In the second step the body’s aim is to eliminate the metabolite out of the body, so the metabolite become more water soluble by UDP-Glucuronosyltransferase. This is why the second effort of the body in drug metabolism is called Phase-II-glucuronidation. Now the drug metabolite is hydrophil (water soluble) enough to leave the body throug the urinary tract.

Last, but not least, we have the phase-III-reactions which decide if a drug is either uptaken into a cell or pumped out of the cell.


These three phases (green in the above exhibit) are the top level structure for our interaction table.

Protein families associated with each phase

Shown in red are the representatives of the protein family (enzymes in phases I & II or transporter proteins in phase III)  of the different reactions.


Details on the different phases

For each phase we only show the most prominent potential drug interactions. If a drug is common but not listed it is not metabilized by one these pathways. An example would be the very commonly used Acetylsalicylic Acid (Aspirin®).

Very rarely used  drugs are added sporadically. The list is therefore not exhaustive. We are updating it regularly to the best of our knowledge.

Possible interaction types for drugs

Type Details
Inhibitor Inhibits the enzymes neede for drug metabolization More Information
Inductor/Activator Increases the amount of enzymes for drug metabolization More Information
Substrate More Information
Prodrug Only turns into an active drug after being metabolized in the body More Information