Reduced platelet thromboxane formation after long-term administration of a dihydropyridine calcium channel blocker: a prospective, double-blind, placebo-controlled study with nitrendipine in borderline hypertensive patients with IDDM-type diabetes mellitus.
Twenty-nine IDDM patients with borderline hypertension were randomly allocated to placebo or nitrendipine treatment. Nitrendipine was given orally at a dosage of 20 mg once daily over 4 weeks. Stimulated platelet thromboxane formation at rest and after standardized, non exhausting exercise was measured by standard methods. In addition, plasma levels of platelet factor 4 and aggregation responses to collagen and ADP were determined. In the treatment group thromboxane formation after stimulation with collagen (0.3 and 1.0 micrograms/ml) and 1 mM arachidonic acid (AA) was reduced in the resting state. Exercise induced change of thromboxane synthesis in response to 1.0 micrograms/ml collagen was significantly lower as compared to placebo (p < 0.05). In parallel, PF4 plasma levels were significantly lowered (p < 0.05). Whole blood aggregation after collagen stimulation (1.0 micrograms/ml) was reduced after 4 weeks of nitrendipine treatment, but ADP (5 microM) induced aggregation was not. These effects of nitrendipine were not seen in platelet rich plasma. In conclusion long-term nitrendipine treatment may inhibit collagen dependent platelet activation in the blood of diabetic patients with borderline hypertension.
Tschoepe
D
D
Cellular Haemostasis Group, Heinrich Heine University, Düsseldorf, FRG.
Homberg
M
M
Roesen
P
P
Gries
F A
FA
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000328:Adult; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D003094:Collagen / Q000494:pharmacology; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000150:complications / Q000503:physiopathology; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000150:complications / Q000188:drug therapy*; D066298:In Vitro Techniques; D008297:Male; D009568:Nitrendipine / Q000627:therapeutic use*; D005082:Physical Exertion; D010919:Placebos; D010974:Platelet Aggregation / Q000187:drug effects; D011446:Prospective Studies; D013931:Thromboxanes / Q000097:blood*
D010919:Placebos; D013931:Thromboxanes; D000244:Adenosine Diphosphate; D003094:Collagen; D009568:Nitrendipine