Reference

The effect of oral administration of dipyrone on the capacity of blood platelets to synthesize thromboxane A2 in man

The effect of oral administration of dipyrone on the capacity of blood platelets to synthesize thromboxane A2 in man. Eldor, A.; Zylber-Katz, E.; Levy, M. (Dep. Hematol., Hadassah Univ. Hosp., Jerusalem, Israel). Eur. J. Clin. Pharmacol., 26(2), 171-6 (English) 1984. CODEN: EJCPAS. ISSN: 0031-6970. DOCUMENT TYPE: Journal CA Section: 1 (Pharmacology) Platelet aggregation and thromboxane A2 (TXA2) [57576-52-0] prodn. induced by arachidonic acid and collagen were studied in healthy volunteers prior to and at various times after the oral administration of a single dose of 1 g dipyrone (I) [68-89-3]. The plasma concns. of 4 dipyrone metabolites were also detd. Dipyrone inhibited platelet aggregation and markedly decreased TXA2 synthesis induced by threshold concns. of both agonists. Maximal inhibition was noted 1 h after drug administration and in some subjects it lasted as long as 72 h. At all times the effect of the drug could be abolished by increasing the concn. of the agonist. This is consistent with a competitive inhibitory effect of dipyrone on prostaglandin synthetase activity. The mean plasma concn. of the main dipyrone metabolite methylaminoantipyrine [519-98-2] at 1 h was 11 mg/mL. There was no correlation between individual plasma levels and the parameters of platelet function. At 24 h the mean concn. of each of the metabolites studied was up to 1 mg/mL, and these levels, too, did not correlate with the biol. effect of the drug.

Cytogenetic effects of metamizol on in vivo bone marrow cells of mice

Cytogenetic effects of metamizol on in vivo bone marrow cells of mice. Reddy, G. Anantha (Dep. Genet., Osmania Univ., Hyderabad 500 007, India). Caryologia, 36(4), 385-92 (English) 1983. CODEN: CARYAB. ISSN: 0008-7114. DOCUMENT TYPE: Journal CA Section: 1 (Pharmacology) The cytogenetic effects of an analgesic antipyretic agent, metamizol (I) [68-89-3], were detd. on bone marrow cells of Swiss mice. The animals were administered 3.9, 7.8, and 15.6 mg once (single-dose series) or 3 times at 24-h intervals (cumulative-dose series), and cytol. prepns. were made from bone marrow cells 24, 48, and 72 h after treatment. Mitotic indexes and chromosome anomalies, including gaps, breaks, fragments, terminal deletions, and polyploid nuclei, were analyzed. A strong inhibition of mitotic frequency was obsd. with the highest doses in the cumulative-dose series, while this was apparently transient in the single-dose series. Gaps were seen frequently. The drug appears to possess an extremely mild clastogenic but no perceivable c-mitotic potency.