anistreplase

Anistreplase is a thrombolytic agent used to dissolve clots in certain cardiovascular emergencies. It is a complex known as anisoylated plasminogen streptokinase activator complex (APSAC), formed by streptokinase bound to plasminogen with an acetylated (anisoyl) group. Administered as a single intravenous infusion, the complex releases active enzyme over time, providing a gradual activation of plasminogen to plasmin.

Mechanistically, anistreplase works by delivering streptokinase to plasminogen, which then converts plasminogen into plasmin, the enzyme that degrades fibrin in clots. The anisoylated modification delays activation, yielding a slower onset of thrombolysis and a more prolonged effect compared with some other thrombolytics. The pharmacokinetic profile reflects this gradual release, resulting in a sustained fibrinolytic state after administration.

Historically, anistreplase was used to treat acute myocardial infarction and other thrombotic occlusions. With the advent of tissue plasminogen activator (tPA)–type therapies and newer agents, its use has declined and it is not always a first-line option in contemporary guidelines. Availability and recommended use now vary by region.

Administration and onset information are guided by clinical protocols, but in general, a single infusion is given, and relief of occlusion may begin within minutes to hours after the start of treatment. The duration of effect can extend for several hours due to the slow release of active enzyme from the complex.

Contraindications include active or recent internal bleeding, history of hemorrhagic stroke, intracranial or spinal surgery, recent major surgery, severe hypertension, and known hypersensitivity to streptokinase or anistreplase. Risks include bleeding and potential allergic reactions, particularly in patients with prior exposure to streptococcal antigens.