Related Experiment Video
Updated: Aug 8, 2026
Ferric Chloride-induced Thrombosis Mouse Model on Carotid Artery and Mesentery Vessel
Published on: June 29, 2015
The effect of ICI 55,897 and clofibrate on platelet function and other tests abnormal in atherosclerosis
Insights
Clofibrate and ICI 55,897 impact platelet function tests in vascular disease patients. While both drugs normalize clotting times, ICI 55,897 shows fewer adverse effects on anti-thrombin activity.
Area of Science:
- Pharmacology
- Vascular Biology
- Thrombosis Research
Background:
- Plasma lipid levels significantly influence platelet function and thrombosis risk.
- Platelet function tests are crucial for assessing thrombotic potential in vascular disease.
- Clofibrate, a lipid-lowering agent, affects certain platelet tests.
Purpose of the Study:
- To investigate the effects of clofibrate and its analogue ICI 55,897 on platelet function tests in patients with vascular disease.
- To compare the efficacy and safety profiles of clofibrate and ICI 55,897 in modulating thrombotic markers.
- To explore potential mechanisms of drug-induced changes in platelet activity, independent of lipid alterations.
Main Methods:
- Administration of clofibrate and ICI 55,897 to patients with vascular disease at risk of thrombosis.
- Monitoring of heparin thrombin clotting time (HTCT), fibrinogen levels, and anti-thrombin activity.
- Comparative analysis of drug effects on these hematological parameters.
Main Results:
- Clofibrate normalized initially short HTCT and fibrinogen levels but worsened anti-thrombin activity.
- ICI 55,897 also normalized HTCT and fibrinogen without adversely affecting anti-thrombin levels.
- ICI 55,897 demonstrated no impact on plasma lipids, unlike clofibrate.
- Direct comparison indicated clofibrate was more effective in normalizing HTCT, despite ICI 55,897's better safety profile regarding anti-thrombin activity.
Conclusions:
- Both clofibrate and ICI 55,897 alter platelet function tests, potentially influencing thrombosis risk in vascular patients.
- ICI 55,897 may offer a safer alternative to clofibrate due to its lack of adverse effects on anti-thrombin activity.
- The mechanisms underlying these drug-induced hematological changes remain unclear and are not directly linked to plasma lipid modifications.
Abstract:
There is considerable evidence that the quantity or quality of plasma lipids influences platelet function tests, and clofibrate reduces high plasma lipids and alters some platelet tests. Clofibrate was accordingly given to patients with vascular disease who were at risk of thrombosis. The heparin thrombin clotting time (HTCT), initially short and thus possibly reflecting increased activation, was regularly returned to normal after about a month's delay. The fibrinogen was also normalized but the initially abnormal anti-thrombic activity became more abnormal. ICI 55,897, an analogue of clofibrate, also normalized the HTCT and the fibrinogen and had no adverse effect on the anti-thrombin levels. This compound has no effect on plasma lipids. If it can be shown that the correction of abnormal tests conveys clinical benefit these findings suggest that ICI 55,897 might clinically be more beneficial than clofibrate. However, direct comparison of clofibrate and ICI 55,897 suggests that clofibrate is more effective in normalizing the HTCT. The mechanism underlying these drug-induced changes are unknown but they cannot be directly related to lipid changes.
Related Concept Videos
01:26Coronary Artery Disease II: Pathophysiology
01:30Atherosclerosis I: Introduction
01:27Atherosclerosis II: Clinical Manifestations and Diagnostic Tests