Usage
Dextran 40 is prescribed for hypovolemia (low blood volume) caused by hemorrhage, surgery, trauma, or burns. It’s also used for prophylaxis of thromboembolic events (blood clots) such as venous thrombosis and pulmonary embolism, particularly in surgical settings. Additionally, it is utilized as a priming fluid in extracorporeal circulation procedures.
It’s classified as a plasma volume expander.
Dextran 40 increases the osmotic pressure of the blood, drawing fluid from the interstitial spaces into the vascular compartment, thereby expanding plasma volume. It also reduces blood viscosity and red blood cell aggregation, improving blood flow.
Alternate Names
Dextran 40 is also known as Low Molecular Weight Dextran (LMD) or Intradex. Brand names include Gentran 40, Rheomacrodex, and LMD.
How It Works
Pharmacodynamics: Dextran 40 exerts its effects by expanding plasma volume, thereby increasing blood pressure and improving tissue perfusion. It also has antithrombotic properties. This occurs by reducing blood viscosity, inhibiting red blood cell aggregation, and decreasing platelet adhesiveness.
Pharmacokinetics: Dextran 40 is administered intravenously. Being a large molecule, it’s not absorbed from the gastrointestinal tract. It is primarily eliminated renally (through the kidneys) with some metabolism occurring in the liver and spleen.
Mode of action: Dextran 40 expands plasma volume by increasing the colloid osmotic pressure within blood vessels. This causes fluid to move from the interstitial spaces into the circulatory system. Its antithrombotic effects are related to reduced blood viscosity, inhibition of red blood cell and platelet aggregation, and enhanced fibrinolysis. It does not bind to specific receptors, inhibit enzymes, or modulate neurotransmitters. The elimination pathway for Dextran 40 is primarily through renal excretion with some metabolic breakdown in the liver and spleen.
Dosage
Standard Dosage
Adults:
- Shock: Initially, 10 mL/kg (up to 20 mL/kg in the first 24 hours) by rapid IV infusion. Maintenance: up to 10 mL/kg/day; maximum 5 days.
- Prophylaxis of Thromboembolism: 500-1000 mL (approximately 10 mL/kg) on the day of surgery, followed by 500 mL/day for 2-3 days. Then 500 mL every 2-3 days for up to 2 weeks based on risk.
- Extracorporeal Circulation: 1-2 g/kg (10-20 mL/kg) added to the perfusion circuit.
Children:
- Shock: Infants: 0.5 g/kg (5 mL/kg). Children: 1 g/kg (10 mL/kg). Adolescents: Similar to adult dosing but with maximum daily limits (2 g/kg initially then 1 g/kg/day).
- Prophylaxis of Thromboembolism: Infants: 0.5 g/kg (5 mL/kg). Children: 1 g/kg (10 mL/kg). Adolescents: Based on the risk (e.g., 50–100 g on the day of surgery).
- Extracorporeal Circulation: Infants: 0.5 g/kg (5 mL/kg). Children: 1 g/kg (10 mL/kg).
Special Cases:
- Elderly Patients: Use with caution due to potential for renal impairment and fluid overload. Adjust dosage accordingly.
- Patients with Renal Impairment: Use with extreme caution. Adjust dosage based on creatinine clearance. Limit to maximum recommended dosages.
- Patients with Hepatic Dysfunction: Use with caution. No specific dosage adjustments provided, but close monitoring recommended.
- Patients with Comorbid Conditions: Careful consideration for patients with cardiac decompensation, hemostatic defects, or extreme dehydration.
Clinical Use Cases
- Intubation/Surgical Procedures/Mechanical Ventilation/ICU Use: Dose as for prophylaxis of thromboembolism.
- Emergency Situations (e.g., shock): Rapid infusion of initial dose as outlined in standard adult and pediatric dosing.
Dosage Adjustments
Dosage adjustments are required for renal or hepatic impairment, considering individual patient characteristics.
Side Effects
Common Side Effects
Mild itching, rash, nausea, vomiting, mild dizziness, weakness, low-grade fever.
Rare but Serious Side Effects
Anaphylactoid reactions (hypotension, wheezing, circulatory collapse, cardiac arrest), bleeding complications, renal failure, pulmonary edema.
Long-Term Effects
No long-term adverse effects specifically identified but prolonged bleeding time and increased risk of bleeding may occur with extended use.
Adverse Drug Reactions (ADR)
Anaphylactoid reactions are significant ADRs requiring immediate discontinuation of Dextran 40 and supportive treatment.
Contraindications
Hypersensitivity to dextran, severe cardiac decompensation, renal disease with severe oliguria or anuria, severe hemostatic defects (including drug-induced), extreme dehydration.
Drug Interactions
Increased risk of bleeding with anticoagulants (heparin, warfarin). Enhanced nephrotoxic effects with some antibiotics (e.g., arbekacin). False elevation of serum glucose and interference with some laboratory tests. Additive medications should not be mixed with dextran solutions.
Pregnancy and Breastfeeding
Pregnancy Category C. Use only if clearly needed, as effects on the fetus are unknown. Excretion into breast milk is unknown. Exercise caution if used during breastfeeding.
Drug Profile Summary
- Mechanism of Action: Plasma volume expansion via increased colloid osmotic pressure; antithrombotic effects via reduced viscosity, inhibition of red blood cell aggregation and platelet adhesion, and enhanced fibrinolysis.
- Side Effects: Itching, rash, nausea, vomiting, dizziness; rarely anaphylactoid reactions and bleeding.
- Contraindications: Hypersensitivity, severe cardiac/renal dysfunction, bleeding disorders.
- Drug Interactions: Anticoagulants, nephrotoxic agents.
- Pregnancy & Breastfeeding: Category C; caution advised.
- Dosage: See above section for detailed dosage information.
- Monitoring Parameters: Blood pressure, urine output, signs of fluid overload, bleeding time, hematocrit.
Popular Combinations
Often used with crystalloid solutions for initial volume resuscitation.
Precautions
Administer 20 mL of Dextran 1 prior to Dextran 40 to reduce the risk of anaphylactoid reactions. Monitor central venous pressure, especially during rapid infusion. Pre-screen for allergies, bleeding disorders, and renal/cardiac dysfunction. Use caution in pregnancy/breastfeeding, children, and the elderly.
FAQs (Frequently Asked Questions)
A: See the Dosage section above for a detailed breakdown.
Q2: What are the main uses of Dextran 40?
A: Primarily used to treat hypovolemia due to various causes (hemorrhage, burns, surgery, trauma), prevent thromboembolic events, and prime extracorporeal circulation circuits.
A: In shock, the initial dose can be infused rapidly as needed. In non-emergency settings, a slower infusion is preferred.
A: Watch for rash, itching, wheezing, hypotension, chest tightness, nausea, vomiting, and other signs of an anaphylactoid reaction.
A: It reduces blood viscosity, inhibits red blood cell aggregation and decreases platelet adhesiveness, and enhances fibrinolysis.
A: It’s a Pregnancy Category C drug. Use only if the benefits clearly outweigh the risks. Consult a specialist for advice.
A: Monitor blood pressure, urine output, central venous pressure (if applicable), signs of fluid overload, bleeding time, and hematocrit.
A: Avoid concomitant use with anticoagulants (increased bleeding risk) and nephrotoxic drugs (enhanced kidney toxicity).
A: No, Dextran 40 is a plasma expander and cannot replace red blood cells or other blood components.
A: Immediately discontinue the infusion and provide supportive treatment as needed, including antihistamines, epinephrine, and corticosteroids.
