Tirofiban Maintenance Infusion Rate in Acute Coronary Syndrome
For a patient with acute coronary syndrome undergoing PCI, administer tirofiban at a maintenance infusion rate of 0.15 mcg/kg/min, which translates to 9 mL/hour for a 60 kg patient using the standard 50 mcg/mL concentration (250 mL premixed bag). 1
Standard Dosing Calculation
The maintenance infusion rate in mL/hour is calculated using the following formula from the FDA label 1:
Infusion rate (mL/hour) = [0.15 mcg/kg/min × patient weight (kg) × 60 min/hour] ÷ 50 mcg/mL
Examples:
- 60 kg patient: (0.15 × 60 × 60) ÷ 50 = 10.8 mL/hour 1
- 70 kg patient: (0.15 × 70 × 60) ÷ 50 = 12.6 mL/hour 1
- 80 kg patient: (0.15 × 80 × 60) ÷ 50 = 14.4 mL/hour 1
Dosing Protocol
Initial bolus: 25 mcg/kg administered intravenously within 5 minutes, followed immediately by the maintenance infusion 1, 2
Duration: Continue infusion for up to 18 hours post-PCI 1, 2
Timing: Initiate tirofiban just prior to or during PCI, not in the pre-catheterization laboratory setting unless specifically indicated 3
Critical Dose Adjustment for Renal Impairment
For patients with creatinine clearance ≤ 60 mL/min, reduce the maintenance infusion rate by 50% to 0.075 mcg/kg/min 1, 2
This adjustment is essential because tirofiban's half-life is prolonged more than three-fold in severe renal insufficiency, significantly increasing bleeding risk without dose reduction 3, 4
Adjusted calculation for renal impairment:
Infusion rate (mL/hour) = [0.075 mcg/kg/min × patient weight (kg) × 60 min/hour] ÷ 50 mcg/mL
- 60 kg patient with CrCl ≤ 60: (0.075 × 60 × 60) ÷ 50 = 5.4 mL/hour 1
- 70 kg patient with CrCl ≤ 60: (0.075 × 70 × 60) ÷ 50 = 6.3 mL/hour 1
Important Clinical Considerations
Concomitant anticoagulation: When using tirofiban with heparin during PCI, administer weight-adjusted heparin (60 IU/kg bolus, maximum 4,000 IU) targeting an ACT of 200-250 seconds 3, 2
Platelet monitoring: Check platelet counts beginning 6 hours after treatment initiation and daily thereafter; discontinue if platelets drop below 90,000/mm³ 1
Bleeding risk: Major bleeding rates with weight-adjusted tirofiban dosing are not significantly different from heparin alone when dosed appropriately 3, 5
Common Pitfalls to Avoid
Do not use the older low-dose regimen (0.4 mcg/kg/min bolus for 30 minutes followed by 0.1 mcg/kg/min maintenance) as this was replaced by the high-dose bolus regimen that achieves >80% platelet inhibition within 5 minutes 2, 3
Do not forget renal dose adjustment: Failure to reduce the infusion rate by 50% in patients with CrCl ≤ 60 mL/min substantially increases bleeding complications 1, 3
Calculate creatinine clearance using actual body weight with the Cockcroft-Gault equation before initiating therapy 1