What is the proper dosing for intravenous (IV) infusion therapy?

Proper Dosing for Intravenous (IV) Infusion Therapy

IV infusion dosing must follow medication-specific guidelines with attention to concentration, rate of administration, and patient factors such as weight, age, and renal function to ensure safety and efficacy.

General IV Infusion Principles

Concentration and Rate Guidelines

• IV infusion concentrations should be standardized to minimize medication errors 1
• For most medications, concentrations should not exceed 5 mg/mL 2
• Administration rates should generally not exceed 10 mg/min in adults 2
• Higher concentrations (up to 10 mg/mL) may be used for fluid-restricted patients but increase the risk of infusion-related events 2

Duration Guidelines

• Most IV medications should be administered over at least 60 minutes 2
• Rapid infusion rates can lead to adverse effects including hypotension, arrhythmias, and tissue damage from extravasation 3

Medication-Specific Dosing Guidelines

Vasoactive Medications

• Dopamine: 2-20 μg/kg/min, titrated to desired clinical effect 3

  • Low dose (1-5 μg/kg/min): Primarily dopaminergic and β-adrenergic effects
  • Higher doses: α-adrenergic effects predominate

• Epinephrine: 0.1-1.0 μg/kg/min for shock, titrated from lowest dose 3

  • May require up to 5 μg/kg/min in severe cases
  • Monitor for tachyarrhythmias and hypertension

Antimicrobials

• Vancomycin: 2
  • Adults: 2g daily divided as 500mg every 6 hours or 1g every 12 hours
  • Pediatric patients: 10 mg/kg every 6 hours
  • Neonates: Initial 15 mg/kg, then 10 mg/kg every 12 hours (first week of life) or every 8 hours thereafter
  • Adjust based on renal function: ~15 times the glomerular filtration rate in mL/min

Antineoplastic Regimens

• mFOLFOX6: 3

  • Oxaliplatin 85 mg/m², IV over 2 hours, day 1
  • Leucovorin 400 mg/m², IV over 2 hours, day 1
  • 5-FU 400 mg/m² IV bolus day 1, followed by 1,200 mg/m²/day × 2 days (total 2,400 mg/m²) as continuous infusion
  • Repeat every 2 weeks

• FOLFIRI: 3

  • Irinotecan 180 mg/m², IV over 30-90 minutes, day 1
  • Leucovorin 400 mg/m², IV infusion to match duration of irinotecan, day 1
  • 5-FU 400 mg/m² IV bolus day 1, followed by 1,200 mg/m²/day × 2 days as continuous infusion
  • Repeat every 2 weeks

Opioid Infusions

• Fentanyl: 4
  • Starting dose: 0.1-1.0 μg/kg/min
  • No absolute maximum dose; titrate to clinical effect while monitoring for respiratory depression
  • When converting from IV morphine to IV fentanyl, use 100:1 ratio (morphine:fentanyl)

Patient-Specific Considerations

Renal Impairment

• Dosage adjustment is essential for patients with impaired renal function 2
• For many medications, calculate dosage based on creatinine clearance
• Monitor drug levels when appropriate (e.g., vancomycin)

Age Considerations

• Pediatric patients require weight-based dosing 3, 2
• Elderly patients often require dose reductions due to decreased renal function 2
• Neonates and premature infants may need longer dosing intervals 2

Weight Considerations

• Obese patients may require modified dosing strategies 2
• Specify whether dosing is based on actual body weight, ideal body weight, or adjusted body weight

Safety Considerations

Extravasation Risk

• Vasoactive medications carry significant extravasation risk 3, 5
• Treatment for extravasation: Phentolamine (0.1-0.2 mg/kg up to 10 mg diluted in 10 mL of 0.9% sodium chloride) injected intradermally at extravasation site 3, 5
• Consider peripheral administration of vasopressors only with close monitoring; extravasation rate is approximately 2% 5

Monitoring Requirements

• Continuous monitoring of vital signs during infusion of high-risk medications
• Regular assessment of IV site for signs of infiltration or inflammation
• For opioid infusions, respiratory monitoring is essential 4

Common Pitfalls to Avoid

1. Dead volume issues: The infusion set dead volume may contain significant drug mass that can be inadvertently delivered as a bolus 6

2. Carrier flow interruptions: Abrupt cessation of carrier flow can significantly reduce drug delivery 6

3. Lag time after adjustments: Changes in carrier flow or drug dosing may require significant time before reaching steady-state drug delivery 6

4. Multiple concentration confusion: Using multiple concentrations of the same medication increases error risk 1

5. Inadequate monitoring: Failure to monitor for adverse effects or therapeutic response can lead to patient harm

By following these guidelines and considering patient-specific factors, clinicians can optimize the safety and efficacy of IV infusion therapy.