Alteplase was approved by the FDA in November 1987. In June 1996, it was approved for the treatment of acute ischemic stroke.

Altaplase is a biosynthetic form of the human tissue plasminogen activator (t-PA), an enzyme that converts plasminogen to plasmin, used to dissolve blood clots rapidly and selectively, especially in the treatment of heart attacks.

It is produced by recombinant DNA technology from genetically modified Chinese hamster ovary cells. Although alteplase is considerably more expensive than streptokinase,  which is a proteolytic enzyme produced by hemolytic streptococci, capable of dissolving fibrin and used medically to dissolve blood clots, alteplase does not have the capacity to act as an antigen.

Alteplase is not an orally taken drug. It is a blood clot dissolving agent. Clinically, it is used for dissolving severe thromboembolism  of the lungs or severe coronary arterial thromboembolism associated with evolving heart attacks that affect the whole thickness of the heart muscle. Alteplase is also being investigated for use in unstable sudden severe chest pain. Alteplase is administered by IV infusion. Plasma concentrations are related to dose and rate of administration, although patients with myocardial infarction (MI) show greater variation than do healthy individuals. In MI patients, an infusion of alteplase at a rate of 4—8.3 µg/kg/min resulted in steady state plasma concentrations of 0.52—1.4 µg/ml; although, there was large variability among patients receiving infusions at the same rate. In MI patients receiving accelerated infusion of alteplase (i.e., 15 mg alteplase as an IV bolus, then 50 mg IV over 30 minutes, then 35 mg over 60 minutes), the mean steady state plasma concentrations of alteplase were 3.2 µg/ml; however, the half-life was similar to that reported with conventional administration. 

The distribution of this agent has not been described. It is unknown whether alteplase crosses the placenta or is excreted into breast milk. Hepatic clearance is the predominant route of metabolism. More than 50% of the drug is cleared following discontinuation of IV infusion and 80% within 10 minutes. Limited studies in patients with myocardial infarction and patients with thrombo-occlusive disease indicate that the terminal half-life of alteplase is approximately 45 and 30 minutes, respectively. There is some evidence to suggest a longer elimination half-life in patients with hepatic impairment. Exogenous t-PA has been shown to be primarily excreted in the urine (80%).

(not finished editing into simple English)