Stimulation of Endogenous Fibrinolysis
Cornelis Kluft in Tissue-Type Plasminogen Activator (t-PA): Physiological and Clinical Aspects, 1988
Ancrod and batroxobin are thrombin-like enzymes purified from pit viper venoms. Their pharmacology,114 effects on hemostasis and hemorheology,115 and clinical effects115 have recently been reviewed. Unlike thrombin, they do not release fibrinopeptide B, activate factor XIII, or activate platelets; a relatively soluble type of fibrin is formed which is rapidly removed from the circulation, resulting in decreased fibrinogen levels and increased levels of fibrin(ogen) degradation products.114,115 The reduction in plasma fibrinogen lowers plasma and blood viscosity and reduces platelet aggregation.115 Ancrod is an effective alternative to heparin for treatment of venous thrombosis,115 and two double-blind, placebo-controlled trials showed that ancrod reduced the incidence or extent of venographic deep vein thrombosis after hip surgery.116,117 The clinical efficacy of ancrod and batroxobin in arterial disease awaits confirmation in controlled trials.115
Rheology of Disease
Gordon D. O. Lowe in Clinical Blood Rheology, 2019
As discussed above, fibrinogen levels rise within 6 to 8 hr of surgery:8 the concentration may double within 24 hr and tends to peak about 4 days after surgery, falling towards normal over the next 10 days. This increase in fibrinogen and in certain serum globulins, tends to increase plasma viscosity, red cell aggregation and blood viscosity: however the moderate fall in hematocrit in the first few days after surgery usually outweighs the protein changes, so that blood viscosity falls.31,33-38 Correction of blood viscosity to a standard hematocrit ex vivo reveals the increase in blood viscosity which would otherwise result.31,33-37 The importance of fibrinogen was shown in a controlled trial of defibrination with subcutaneous ancrod (Chapter 8, Volume II) in patients with hip fractures.36 Ancrod significantly reduced plasma and blood viscosity, and maintained blood viscosity in the normal range even when corrected for hematocrit.36 A fall in plasma viscosity has been observed on the first postoperative day, despite increased fibrinogen levels: this may reflect falls in serum proteins due to consumption or hemodilution.38
Miscellaneous: Dextran, Dermatan Sulfate, Low Molecular Weight Heparinoids (Org 10172), Pentosan Polysulfate (Sp54), Defibrinating Agents (Ancrod And Reptilase)
Hau C. Kwaan, Meyer M. Samama in Clinical Thrombosis, 2019
The most common and most important complication encountered in Ancrod and Reptilase therapy was bleeding. It was reported that 3 out of a series of 58 patients (5%) had bleeding during the course of Ancrod therapy.58 Bleeding was due, respectively, to aspirin-induced gastritis, peptic ulcer, and vaginal origin of unknown etiology. In another series of 94 patients, bleeding occurred in 7 (7.5%) from such causes as ulcerative colitis, hiatus hernia, peptic ulcer, and gastrocnemius rupture; also, in the retroperitoneum and into the skin at sites of drug rash.43 However, when Ancrod was given immediately after surgical operations, there was bleeding in 6 of 11 patients (55%), with such severity in 3 that therapy had to be stopped.43 As such, it was felt that Ancrod is contraindicated within 48 h of surgical operation.
Polybia occidentalis and Polybia fastidiosa venom: a cytogenotoxic approach of effects on human and vegetal cells
Published in Drug and Chemical Toxicology, 2021
Marcel José Palmieri, Amanda Ribeiro Barroso, Larissa Fonseca Andrade-Vieira, Marta Chagas Monteiro, Andreimar Martins Soares, Pedro Henrique Souza Cesar, Mariana Aparecida Braga, Marcus Vinicius Cardoso Trento, Silvana Marcussi, Lisete Chamma Davide
Some components of the venom can be benefic when isolated and administered in the proper doses, as there are many medicines fabricated from isolated fractions of venoms, such as antihypertensive (e.g., Captopril and Ranatensin), anticoagulants (e.g., Ancrod, Batroxobin, and Echistatin) (Koh and Kini 2012), drugs against diabetes mellitus, and analgesics (Koh and Kini 2012, Prashanth et al. 2017).
Related Knowledge Centers
- Anticoagulant
- Fetus
- Serine Protease
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- Venombin A
- Thrombin
- Coagulopathy