{"id":3043,"date":"2026-08-22T21:15:00","date_gmt":"2026-08-22T20:15:00","guid":{"rendered":"https:\/\/seamlessbio.de\/?page_id=3043"},"modified":"2026-08-23T00:15:32","modified_gmt":"2026-08-22T23:15:32","slug":"what-is-drug-drug-interaction-ddi","status":"publish","type":"page","link":"https:\/\/seamlessbio.de\/de\/what-is-drug-drug-interaction-ddi\/","title":{"rendered":"What is a Drug-Drug Interaction (DDI)?"},"content":{"rendered":"
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Quick Definition<\/p>\n

What is a Drug-Drug Interaction (DDI)?:<\/strong> A drug-drug interaction (DDI) is an alteration in the pharmacokinetics or pharmacodynamics of one drug caused by concurrent administration of another. Pharmacokinetic DDIs occur when one drug affects the absorption, distribution, metabolism, or excretion (ADME) of another \u2014 most commonly through inhibition or induction of CYP450 enzymes or transporter proteins.<\/p>\n<\/div>\n

Transporter vs enzyme DDIs<\/h2>\n

Enzyme-mediated DDIs (CYP450) affect drug metabolism \u2014 chemical transformation into metabolites. Transporter-mediated DDIs affect drug transport across membranes \u2014 intestinal absorption (P-gp, BCRP), hepatic uptake (OATP1B1\/1B3), renal secretion (OCT2, OAT1\/3, MATE1\/2-K), biliary excretion (BSEP, MRP2). The most complex DDIs involve both mechanisms simultaneously.<\/p>\n

Regulatory DDI assessment package<\/h2>\n

Before first-in-human: in vitro DDI assessment for CYP450 inhibition (reversible and time-dependent) for CYP1A2, 2B6, 2C8, 2C9, 2C19, 2D6, 3A4; CYP induction (1A2, 2B6, 3A4); and transporter substrate\/inhibitor for P-gp, BCRP, OATP1B1\/1B3, OCT2, OAT1\/3, MATE1\/2-K, with BSEP and MRP2 additionally recommended.<\/p>\n

Key Facts<\/h2>\n