EFFECTIVE LONG-TERM INHIBITION OF THROMBOXANE PRODUCTION BUT NOT OF SEROTONIN RELEASE IN PATIENTS WITH CORONARY HEART-DISEASE BY 30 MG D ACETYLSALICYLIC-ACID DOSAGE/

Efficacy of aspirin (Acetylsalicylic acid, ASA) antiaggregatory preven tion was demonstrated in a series of clinical trials. The recommended ASA doses decreased gradually and doses 50-30 mg ASA/d are intensively studied at the present time. A group of 42 patients with coronary hea rt disease was evaluated: (1) Basal TXB2 production during spontaneous blood clotting was 360 +/- 37.6 ng/ml; (2) Two initial doses were tes ted: while 200 mg ASA inhibited, during spontaneous blood clotting, me dian TXB2 production by 99.9% (serum TXB2 concentration 1.35 ng/ml), 3 0 mg ASA median inhibition was just 42.0% (serum TXB2 151 ng/ml); (3) 30 mg ASA/d maintenance dose was evaluated for 3 months. The median TX B2 production inhibition was 98.5% (serum TXB2 3.75 ng/ml, first month ) and 94.0% (serum TXB2 14.2 ng/ml, third month); (4) Four patients di d not respond sufficiently, because of noncompliance verified by the d etermination of salicyluric acid urinary excretion, the lower limit of excretion being <3 mu mol/2 h; (5) Both initial and maintenance ASA d ose decreased metabolic TXA(2) endproducts in urine; (6) 5HT platelet release did not decrease; (7) Potential changes of 5HT metabolic elimi nation were excluded by the simultaneous determination of 5-hydroxyind oleacetic acid (5HIAA). In conclusion, 200 mg initial dose and 30 mg A SA/d maintenance dose are suggested to be maximally inhibitory for TXB 2 production without influence on 5HT release.