Tirofiban Dosing for 100 kg Patient with ACS
For a 100 kg patient with acute coronary syndrome, administer tirofiban as a 25 mcg/kg IV bolus (2,500 mcg total) over 5 minutes, followed by a continuous infusion of 0.15 mcg/kg/min (15 mcg/min) for up to 18 hours. 1
Specific Dose Calculations
Bolus Dose:
- 25 mcg/kg × 100 kg = 2,500 mcg (2.5 mg)
- Administer over 5 minutes 1
Maintenance Infusion:
- 0.15 mcg/kg/min × 100 kg = 15 mcg/min
- Continue for up to 18 hours 1
- If using a 250 mL bag containing 12.5 mg (50 mcg/mL), the infusion rate would be 18 mL/hour 1
Critical Renal Function Assessment
Before administering, you must check creatinine clearance. 1
- If CrCl > 60 mL/min: Use standard dosing as above 1
- If CrCl ≤ 60 mL/min: Reduce maintenance infusion by 50%:
- Bolus: 25 mcg/kg (2,500 mcg) over 5 minutes
- Infusion: 0.075 mcg/kg/min (7.5 mcg/min or 9 mL/hour) 1
The half-life of tirofiban is prolonged more than three-fold in severe renal insufficiency, making dose reduction essential to prevent excessive bleeding 2, 3
Clinical Context and Timing
Tirofiban should be initiated:
- In combination with aspirin and heparin for NSTE-ACS patients with elevated troponin scheduled for early PCI 2
- Just prior to or during percutaneous coronary intervention 4
Duration of therapy:
- Continue infusion for 12-24 hours post-PCI (24 hours for tirofiban specifically) 4
- The FDA label allows up to 18 hours total 1
Concomitant Anticoagulation
Weight-adjusted heparin dosing when used with tirofiban:
- 60 IU/kg bolus (maximum 4,000 IU) at time of PCI 4
- This is reduced from the standard 85 IU/kg when GP IIb/IIIa inhibitors are used concomitantly 4
- Target ACT of 200-250 seconds (lower than the 250-300 seconds used without GP IIb/IIIa inhibitors) 5
Evidence Supporting This Regimen
The high-dose bolus regimen (25 mcg/kg) produces rapid platelet inhibition within 5 minutes and achieves >80% platelet aggregation inhibition, which is superior to the older standard-dose regimen (10 mcg/kg bolus) 6, 7. This dosing reduces death and myocardial infarction by 3% absolute risk (relative risk reduction 0.79) when PCI is performed within 5 days 2.
Safety Monitoring
Monitor for bleeding complications:
- Major bleeding rates with tirofiban are not significantly different from heparin alone when weight-adjusted dosing is used 2, 6
- Check platelet count at baseline and monitor for thrombocytopenia (occurs in approximately 1% of patients) 2, 3
- Platelet function recovers within 4-6 hours after infusion cessation 2, 3, 6
Common Pitfalls to Avoid
- Do not use the older standard-dose regimen (10 mcg/kg bolus with 0.10 mcg/kg/min infusion), as it provides insufficient platelet inhibition 7
- Do not forget to reduce the dose by 50% for maintenance infusion if CrCl ≤ 60 mL/min 1
- Do not use tirofiban without concomitant heparin in NSTE-ACS, as the PRISM-PLUS trial showed increased mortality with tirofiban monotherapy 6
- Do not exceed the maximum heparin bolus of 4,000 IU when using GP IIb/IIIa inhibitors to minimize bleeding risk 4