Reteplase (
Retavase) is a
plasminogen activator, mimicking endogenous
tissue plasminogen activator (t-PA), a
serine protease, converting
plasminogen to
plasmin and thereby precipitating thrombolysis. It is a third-generation recombinant form of t-PA that operates in the presence of
fibrin (i.e. it is
fibrin specific).
Reteplase can be administered as a bolus dose (nonweight-based) rather than an infusion, which promotes rapid and safe administration. The ease of administration of this
reteplase dosage regimen (two 10U bolus doses, each over 2 minutes, 30 minutes apart) is conducive to prehospital initiation of thrombolytic treatment in patients with
ST-segment elevation myocardial infarction (
STEMI), which reduces the
time to treatment, a critical factor in improving long-term survival. In large randomized clinical trials of patients with
STEMI,
reteplase was superior to
alteplase for coronary artery patency (according to TIMI [thrombolysis in
myocardial infarction] flow) at 60 and 90 minutes, but there was no significant difference between agents for mortality rate and incidence of intracranial
bleeding. The 35-day mortality rates were equivalent for
reteplase and
streptokinase recipients; there was reduced incidence of some
cardiac events with
reteplase versus
streptokinase, but a greater incidence of
hemorrhagic stroke.
Reteplase has also shown thrombolytic efficacy (in nonapproved indications) as a
catheter-directed intra-arterial or
intravenous infusion for peripheral vessel occlusions, as 5-minute bolus doses (in 1U increments) for
acute ischemic stroke, as a low-dose
solution for occluded
catheters or grafts, and as an intravenous double bolus for massive
pulmonary embolism. Across studies in these indications, the incidence of
bleeding complications associated with
reteplase treatment appeared to be similar to that associated with other
thrombolytic agents. With its efficacy, and the ease of administration of the bolus doses potentially minimizing dosage errors when treatment is administered under time pressure,
reteplase is a valuable option for pre- or in-hospital thrombolytic treatment in patients with
STEMI, and is a useful thrombolytic for the treatment of the other thrombotic occlusive disorders described.