Prevention of dextran-induced anaphylactic reactions by hapten inhibition. II. A comparison of the effects of 20 ml dextran 1, 15%, administered either admixed to or before dextran 70 or dextran 40.

The incidence of dextran-induced anaphylactoid/anaphylactic reactions (DIAR) was investigated after hapten inhibition employing two different modes of administration of dextran 1 (Mw 1 000 dalton). The trial was carried out as an open prospective study that comprised 12 060 patients. They were randomized into two groups--one receiving a mixture of 20 ml dextran 1, 15%, (Promiten) and 500 ml dextran 70 (Macrodex) or dextran 40 (Rheomacrodex) (admixture group), the other receiving an intravenous injection of 20 ml dextran 1, 15% before the infusion of dextran 70 or 40 (preinjection group). DIAR were graded according to severity from I to V. In the admixture group eight DIAR of grade II, one of grade IV and one of grade V were observed, while in the preinjection group two DIAR of grade II occurred. The admixture of dextran 1 to dextran 70 or 40 does not prevent the occurrence of severe DIAR in the dose investigated.