RASTAT Injection Premixed is supplied as a sterile solution in water for injection, for intravenous use. The pH of the solution ranges from 5.5 to 6.5 adjusted with hydrochloric acid and/or sodium hydroxide.
Each 100 mL of the premixed, isosmotic intravenous injection contains 5.618 mg tirofiban hydrochloride monohydrate equivalent to 5 mg tirofiban (50 mcg/mL) and the following inactive ingredients: 0.9 g sodium chloride, 54 mg sodium citrate dihydrate, and 3.2 mg citric acid anhydrous.
Each 250 mL of the premixed, isosmotic intravenous injection contains 14.045 mg tirofiban hydrochloride monohydrate equivalent to 12.5 mg tirofiban (50 mcg/mL) and the following inactive ingredients: 2.25 g sodium chloride, 135 mg sodium citrate dihydrate, and 8 mg citric acid anhydrous.
AGGRASTAT Injection Premixed Bolus Vial is supplied as a sterile, isosmotic, concentrated solution for intravenous bolus injection, in 15 mL vials. No dilution is required. Each 15 mL of the premixed, isosmotic intravenous injection bolus vial contains 4.215 mg of tirofiban hydrochloride monohydrate equivalent to 3.75 mg of tirofiban and the following inactive ingredients: 120 mg sodium chloride, 40.5 mg sodium citrate dihydrate, and 2.4 mg citric acid anhydrous and water for injection.
12 CLINICAL PHARMACOLOGY
12.1 Mechanism of Action
AGGRASTAT is a reversible antagonist of fibrinogen binding to the GP IIb/IIIa receptor, the major platelet surface receptor involved in platelet aggregation. When administered intravenously, AGGRASTAT inhibits ex vivo platelet aggregation in a dose- and concentration-dependent manner.
When given according to the PRISM-PLUS regimen of 0.4 mcg/kg/min over 30 minutes followed by a 0.1 mcg/kg/min maintenance infusion, >90% inhibition of platelet aggregation is attained by the end of the 30-minute infusion. When given according to the recommended regimen of 25 mcg/kg followed by a 0.15 mcg/kg/min maintenance infusion, >90% inhibition of platelet aggregation is attained within 10 minutes. Platelet aggregation inhibition is reversible following cessation of the infusion of AGGRASTAT.
12.2 Pharmacodynamics
AGGRASTAT inhibits platelet function, as demonstrated by its ability to inhibit ex vivo adenosine phosphate (ADP)-induced platelet aggregation and prolong bleeding time in healthy subjects and patients with coronary artery disease. The time course of inhibition parallels the plasma concentration profile of the drug.
Following discontinuation of an infusion of AGGRASTAT 0.10 mcg/kg/min, ex vivo platelet aggregation returns to near baseline in 4 to 8 hours in approximately 90% of patients with coronary artery disease. The addition of heparin to this regimen does not significantly alter the percentage of subjects with >70% inhibition of platelet aggregation (IPA), but does increase the average bleeding time, as well as the number of patients with bleeding times prolonged to >30 minutes. Similar platelet aggregation recovery rates are observed following discontinuation of a 0.15 mcg/kg/min infusion.
12.3 Pharmacokinetics
Tirofiban has a half-life of approximately 2 hours. It is cleared from the plasma largely by renal excretion, with about 65% of an administered dose appearing in urine and about 25% in feces, both largely as unchanged tirofiban. Metabolism appears to be limited.
Tirofiban is not highly bound to plasma proteins and protein binding is concentration independent over the range of 0.01 to 25 m |
