dextran 1

Dextran 1 is a low-molecular-weight fragment of dextran, specifically designed as a **hapten inhibitor** to prevent or minimize severe anaphylactic (hypersensitivity) reactions resulting from subsequent administration of therapeutic dextran solutions (such as dextran 40 or dextran 70). Dextran 1 is not a plasma expander or therapeutic dextran; instead, it acts by binding anti-dextran antibodies present in the circulation, thereby blocking anaphylactic reactions that may occur when high molecular weight dextran is administered for plasma volume expansion. Dextran 1, by itself, does not cause plasma volume expansion and is not used for hemodynamic support. It is used immediately prior to clinical dextran infusion as a test and desensitization agent in susceptible individuals, primarily in procedures involving high risk for dextran-induced anaphylaxis.