Effects of dipyridamole, pentoxifylline or dipyridamole plus pentoxifylline on platelet reactivity in patients with ischemic cerebrovascular insufficiency.
Platelet activation and the subsequent platelet recruitment induced by activated platelets released products constitute the initial events of platelet thrombus formation. We have evaluated the recruiting activity of collagen-stimulated whole blood in patients with ischemic cerebrovascular insufficiency. This was done using an experimental approach that allows independent evaluation of platelet activation and recruitment. The effects of of treating the patients with dipyridamole (DIP) (300 mg/day), pentoxifylline (POX) (1200 mg/day) or a combination of the two drugs at the same doses was also evaluated before and after 7, 15, and 45 days of treatment. DIP decreased the recruiting activity in a time-dependent manner, while POX did not show any effect. However, the combined treatment with DIP+POX was more effective than DIP alone in reducing platelet recruitment, which was abolished after 45 days of treatment. Studies using the drugs in vitro indicated a greater inhibitory activity of the drug association than either drug individually. The effects of the drug association in vitro, even at high concentrations, was lower than those observed ex vivo after 45 days of treatment. This suggests that DIP+POX in vivo may have effects that condition a reduced platelet response.
Santos
M T
MT
Research Center, Hospital La Fe, Valencia, Spain.
Vallés
J
J
Aznar
J
J
Yayá
R
R
Perez-Requejo
J L
JL
D000368:Aged; D001792:Blood Platelets / Q000187:drug effects*; D002545:Brain Ischemia / Q000097:blood / Q000188:drug therapy*; D003094:Collagen / Q000494:pharmacology; D004176:Dipyridamole / Q000627:therapeutic use*; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010431:Pentoxifylline / Q000627:therapeutic use*; D010974:Platelet Aggregation / Q000187:drug effects
D004176:Dipyridamole; D003094:Collagen; D010431:Pentoxifylline