effluxinhibitorer

Efflux inhibitors, or effluxinhibitorer in Swedish usage, are compounds that reduce or block the activity of cellular efflux pumps that remove substrates from cells. They are studied primarily to counter antimicrobial resistance in bacteria and to overcome multidrug resistance in cancer, but may also affect other physiological processes where efflux transporters play a role.

Most efflux pumps belong to families such as RND (resistance-nodulation-division), MFS (major facilitator superfamily), ABC (ATP-binding cassette), and SMR (small multidrug resistance). In bacteria, efflux inhibitors can increase intracellular concentrations of antibiotics and other toxic compounds, thereby restoring or enhancing antimicrobial activity. In cancer, inhibitors of P-glycoprotein and related transporters aim to increase intracellular chemotherapy agents.

Mechanisms of inhibition vary. Some compounds block energy input or conformational changes of the pump, others compete with substrates for binding, and some disrupt the proton motive force. Some inhibitors are nonspecific and affect multiple transporters, while others are more selective. Many candidates are of experimental value in laboratory settings; only a few have achieved clinical use due to toxicity, pharmacokinetic interactions, or limited efficacy.

Common examples include laboratory tools such as phenyl-arginine-β-naphthylamide (PAβN), verapamil, and reserpine, as well as cancer-related inhibitors like tariquidar and elacridar (GF120918). Natural products and drug-like compounds from various sources have also been investigated as EPIs.

Limitations include potential toxicity to host cells, unpredictable drug interactions, and the evolution of resistant efflux pumps. Research continues to identify safer, more effective inhibitors and to define contexts in which efflux inhibition can meaningfully improve therapy.