Chemistry - A branched polysaccharide used intravenously as a plasma volume expander, dextran70 occurs as a white to light yellow amorphous powder. It is freely soluble in water and insoluble inalcohol. Dextran 70 contains (on average) molecules of 70, 000 daltons. Each 500 ml of thecommercially available 6% dextran 70 in normal saline provides 77 mEq of sodium.
Storage, Stability, CompatibilityDextran 70 injection should be stored at room temperature;preferably in an area with little temperature variability. While only clear solutions should be used, dextran flakes can form but can be resolubolized by heating the solution in a boiling water bathuntil clear, or autoclaving at 110°C for 15 minutes. Dextran 70 is compatible with many othersolutions and drugs; refer to specialized references (e.g. Trissel) for more information.
Pharmacology - DEXTRAN 70Dextran 70 has osmotic effects similarly to albumin. Dextran's colloidal osmoticeffect draws fluid into the vascular system from the interstitial spaces, resulting in increasedcirculating blood volume.
Uses, IndicationsDextran 70 is a relatively low cost colloid for the adjunctive treatment of hypovolemic shock.
Pharmacokinetics - DEXTRAN 70After IV infusion, circulating blood volume is increased maximally withinone hour and effects can persist for 24 hours or more. Approximately 20-30% of a given doseremains in the intravascular compartment at 24 hours and it may be detected in the blood 4-6 weeksafter dosing. Dextran 70 is slowly degraded to glucose by dextranase in the spleen and thenmetabolized to carbon dioxide and water. A small amount may be excreted directly into the gut andeliminated in the feces.
Contraindications, Precautions, Reproductive SafetyPatients overly susceptible to circulatoryoverload (severe heart or renal failure) should receive dextran 70 with great caution. Dextran 70 iscontraindicated in patients with severe coagulopathies and should be used with caution in patientswith thrombocytopenia as it can interfere with platelet function. Do not give dextran IM. Patients onstrict sodium restriction should receive dextran cautiously as a 500 ml bag contains 77 mEq ofsodium
Adverse Effects, WarningsModerate to life threatening reactions appear to rare in the dog.
Dextran 70 may increase bleeding time and decrease von Willebrand's factor antigen and factor
VIII activity. This apparently does not usually cause clinical bleeding in dogs.
Anaphylactoid reactions are not that rare in humans, but apparently are very rare in dogs. Dextran70 has only been rarely associated with acute renal failure, unlike dextran 40. In humans, GI effects(abdominal pain, nausea/vomiting) have been reported with use of dextran 70.
Overdosage - The drug should be dosed and monitored carefully as volume overload may result.
Drug InteractionsDextran reportedly has no drug interactions that are clinically significant.
Lab Interactions - Dextran 70 may interfere with blood cross-matching as it can cross-link withred blood cells and appear as rouleaux formation. Isotonic saline may be used to negate this effect.
Blood glucose levels may be increased as dextran is degraded. Falsely elevated bilirubin levelsmay be noted; reason unknown.