Streptokinase is generally avoided as a repeat thrombolytic agent after an initial dose given weeks earlier. The reason is:

• A Tachyphylaxis at the plasminogen receptor
• B Cross-resistance with urokinase receptors
• C Irreversible depletion of circulating plasminogen
• D Neutralising antibodies formed against the bacterial protein ✓

Explanation

Streptokinase is an antigenic protein derived from beta-haemolytic streptococci. Antistreptococcal antibodies form within days of infusion and persist for months to years, neutralising subsequent doses and risking allergic reactions including anaphylaxis. Alteplase or tenecteplase, being human tissue plasminogen activator analogues, are non-immunogenic and are used instead. Plasminogen depletion does not occur, ruling out C.

Reference: Goodman and Gilman's The Pharmacological Basis of Therapeutics, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.