Usage
- Dextran 70 is prescribed for hypovolemic shock caused by hemorrhage, burns, surgery, or trauma. It is also used for prophylaxis of thromboembolic events (such as deep vein thrombosis and pulmonary embolism) in surgical patients. It can also be used as an intrauterine irrigant to aid in visualization during hysteroscopy and as an ophthalmic solution for dry eyes.
- Pharmacological Classification: Plasma volume expander. It also has some antithrombotic properties.
- Mechanism of Action: Dextran 70 increases the osmotic pressure of the blood, drawing fluid from the interstitial space into the intravascular space. This expands plasma volume and improves blood flow. The antithrombotic effect is related to its interference with platelet function and the coagulation cascade.
Alternate Names
- Macrodex
- Intradex
- Gentran 70
How It Works
- Pharmacodynamics: Dextran 70 expands plasma volume, increases cardiac output, and improves tissue perfusion. It can also reduce blood viscosity and improve microcirculation.
- Pharmacokinetics:
- Absorption: Administered intravenously, so absorption is not applicable.
- Metabolism: Primarily excreted unchanged by the kidneys. Some metabolism to glucose occurs.
- Elimination: Renal excretion is the main route of elimination.
- Mode of Action: Exerts its primary effect by increasing plasma colloid osmotic pressure, resulting in fluid movement from the interstitial space to the vascular compartment. Its antithrombotic actions involve interference with platelet aggregation and function, reduction in blood viscosity, and coating of the vascular endothelium.
Dosage
Standard Dosage
Adults:
- Hypovolemic shock: Initially 500-1000 mL of a 6% solution infused intravenously at a rate of 20-40 mL/min. The maximum dose is 20 mL/kg in the first 24 hours, followed by 10 mL/kg/day. The total duration of therapy should not exceed 5 days.
- Thromboembolic prophylaxis: 500-1000 mL of a 6% solution infused intravenously during or immediately following surgery. 500 mL can be given the following day and then on alternate days for up to two weeks in high-risk patients.
Children:
- Data on pediatric dosing are limited. In hypovolemic shock, an initial dose of 10 mL/kg (6% solution) can be given intravenously, followed by a maximum daily dose of 20 mL/kg for the first 24 hours, then 10 mL/kg/day. Treatment should not exceed 5 days.
- For thromboembolic prophylaxis, children weighing under 50 kg can receive up to 10 mL/kg/day, while those weighing 50 kg or more can receive adult doses.
Special Cases:
- Elderly Patients: Caution should be exercised due to potential decreased renal function.
- Patients with Renal Impairment: Contraindicated in patients with severe renal failure, anuria, or oliguria. Dose reduction is necessary in moderate renal impairment.
- Patients with Hepatic Dysfunction: Use with caution.
- Patients with Comorbid Conditions: Use cautiously in patients with congestive heart failure and bleeding disorders. Pre-existing edema and dehydration should be corrected before administration.
Clinical Use Cases
- Intubation: Can be used to maintain hemodynamic stability during intubation in patients at risk of hypovolemia. Dosage should be titrated according to the patient’s clinical condition.
- Surgical Procedures: Used in various surgical settings for volume expansion and thromboembolic prophylaxis, with dosages as described in the standard dosage section.
- Mechanical Ventilation: May be used in mechanically ventilated patients with hypovolemia to maintain adequate circulating volume and improve oxygen delivery. Dosage should be individualized.
- Intensive Care Unit (ICU) Use: Frequently used in the ICU to manage hypovolemic shock and maintain hemodynamic stability in critically ill patients.
- Emergency Situations: Plays a vital role in the immediate management of hypovolemic shock due to trauma or other emergencies. Rapid infusion may be necessary.
Side Effects
Common Side Effects
- Nausea, vomiting, fever, mild allergic reactions (itching, rash), joint pain.
Rare but Serious Side Effects
- Severe anaphylactoid reactions (hypotension, bronchospasm, cardiac arrest), renal failure, bleeding complications.
Adverse Drug Reactions (ADR)
- Anaphylaxis, angioedema, acute renal failure, pulmonary edema, severe bleeding.
Contraindications
- Hypersensitivity to dextran.
- Severe renal failure, anuria, or oliguria.
- Severe bleeding disorders.
- Severe congestive heart failure.
Drug Interactions
- Enhances the effects of anticoagulants (e.g., warfarin, heparin).
- May interfere with blood typing and cross-matching.
Pregnancy and Breastfeeding
- Pregnancy Safety Category: C. Use only if the potential benefits justify the potential risks to the fetus. Anaphylactic reactions during pregnancy have been reported to cause fetal complications, including death.
- Breastfeeding: Limited data available. Use with caution.
Drug Profile Summary
- Mechanism of Action: Plasma volume expander; increases intravascular oncotic pressure.
- Side Effects: Nausea, vomiting, fever, allergic reactions, joint pain, anaphylaxis, bleeding.
- Contraindications: Dextran hypersensitivity, renal failure, severe bleeding disorders, CHF.
- Drug Interactions: Anticoagulants.
- Pregnancy & Breastfeeding: Category C; use with caution.
- Dosage: See detailed dosage guidelines above.
- Monitoring Parameters: Blood pressure, heart rate, urine output, renal function, signs of bleeding/allergic reactions.
Popular Combinations
- Often used in conjunction with crystalloid solutions (e.g., normal saline, lactated Ringer’s) for fluid resuscitation.
Precautions
- Monitor for signs of hypersensitivity reactions.
- Correct dehydration prior to administration.
- Use with caution in patients with renal impairment, heart failure, or bleeding disorders.
FAQs (Frequently Asked Questions)
A: The dosage depends on the indication and patient-specific factors. Refer to the detailed dosage guidelines above for specific recommendations.
A: Nausea, vomiting, fever, mild allergic reactions, and joint pain are commonly reported.
A: Contraindications include hypersensitivity to dextran, severe renal failure, severe bleeding disorders, and severe congestive heart failure.
A: It can potentiate the effects of anticoagulant medications. It may also interfere with blood typing and cross-matching.
A: Dextran 70 is a Pregnancy Category C drug, meaning it should only be used if the potential benefits outweigh the risks to the fetus. Its use during breastfeeding should be approached with caution.
A: Closely monitor blood pressure, heart rate, urine output, renal function, and signs of bleeding or allergic reactions.
A: It is administered intravenously as an infusion.
A: Its antithrombotic action involves decreasing blood viscosity, reducing platelet adhesiveness and aggregation, and coating the vascular endothelium.
Q9: What is the difference between Dextran 40 and Dextran 70?
A: Dextran 40 and Dextran 70 are similar but differ in their molecular weight. Dextran 70 has a higher molecular weight and remains in circulation longer than Dextran 40. They have similar clinical uses but can have different effects on coagulation.
A: Low concentrations of dextran 70 are used in ophthalmic solutions for dry eyes. It acts as a lubricant and helps retain moisture on the ocular surface.
