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Biomedical subjects

C Staiger

Publications and source records attributed to C Staiger.

At least 37 records · Page 2Linked to original sources
PubMed1984

Inhibitory effects of the selective thromboxane receptor antagonist BM 13.177 on platelet aggregation, vasoconstriction and sudden death.

BM 13.177 (0.1-100 microM) produced a concentration-dependent reduction of the platelet shape change, aggregation and (3H)serotonin release induced by the stable PGH2 analogues U 46619 and U 44069 or exogenous and endogenous arachidonic acid, the latter mobilized by hydrogen peroxide or collagen. BM 13.177 (100 microM) did not inhibit the primary platelet activation by ADP, serotonin, thrombin or collagen in washed platelets or citrated PRP that had been pre-treated with ASA (acetylsalicylic acid). The formation of TXB2 triggered by 100 microM hydrogen peroxide or 10 microM arachidonic acid was not influenced by BM 13.177 (10 microM). In spiral strips of rat and rabbit aorta, BM 13.117 markedly reduced the vasoconstriction triggered by U 46619 and PGF2 alpha. BM 13.177 did not inhibit the K+-or noradrenaline-induced constriction. The concentration/response curves of the U 46619-stimulated platelet shape change and of the vasoconstriction induced by U 46619 and PGF2 alpha were shifted in parallel to the right by BM 13.177, implicating a competitive antagonism. The pAx values were about the same in these models which indicates that BM 13.177 does not differentiate between the thromboxane receptors in human platelets and rabbit aorta. In mice, BM 13.177 prevented in a dose-dependent fashion the sudden death and the symptoms of respiratory depression and shock induced by i.v. injections of U 46619 or arachidonic acid. BM 13.177 did not exert partial agonist activity in the in vitro and in the animal models.(ABSTRACT TRUNCATED AT 250 WORDS)

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1984

[Comparative study of the effect of famotidine and cimetidine on antipyrine pharmacokinetics in the human].

In a randomized order the pharmacokinetics of antipyrine were studied following a 5 days treatment period with placebo, 1000 mg cimetidine and 40 mg famotidine daily, respectively in 7 healthy volunteers. In contrast to cimetidine, famotidine did not significantly affect the disposition of antipyrine in these subjects. Famotidine like the other guanidino-thiazole containing compound tiotidine appears to be free from this unwanted effect on drug metabolism in the liver.

Adult↗
PubMed1984

[Effect of metronidazole on phenazone metabolism].

Nine volunteers received in random order on three occasions either 15 mg/kg phenazone (antipyrine; in the following called phenazone, INN), 15 mg/kg phenazone and 1000 mg cimetidine or 15 mg/kg phenazone and 1000 mg metronidazole. Cimetidine prolonged phenazone half-life from 12.7 +/- 1.0 h to 15.5 +/- 1.0 h (p less than 0.05) and decreased total plasma clearance of phenazone from 40.9 +/- 3.9 ml/min to 33.9 +/- 2.9 ml/min (p less than 0.05). When metronidazole was given with phenazone to the volunteers no change of phenazone pharmacokinetics in plasma occurred. Urinary excretion of the main oxidative metabolites of phenazone (4-hydroxyphenazone, 3-hydroxymethylphenazone and norphenazone) was unaffected during cimetidine as well as metronidazole treatment. Both metronidazole and cimetidine potentiate the anticoagulant effect of warfarin. In contrast it could be shown that cimetidine does not interact with the metabolism of phenprocoumon. Whether metronidazole interferes with the pharmacokinetics of phenprocoumon should be studied in further investigations.

Adult↗
PubMed1984

Effect of the thromboxane synthetase inhibitor Dazoxiben (UK 37-248) on the metabolism of antipyrine in patients with enhanced platelet aggregation.

The effect of the imidazole derivative Dazoxiben (400 mg daily for 1 week) on antipyrine metabolism was examined in six patients with enhanced platelet aggregation. No significant change in antipyrine saliva pharmacokinetics occurred before or after Dazoxiben treatment. The rate of formation of the three main oxidative antipyrine metabolites was similar before and after Dazoxiben. Although Dazoxiben belongs chemically to the imidazole derivatives, which exhibit inhibitory activity on drug metabolism, no influence on antipyrine disposition could be detected.

Aged↗
PubMed1983

Effect of single and multiple doses of sulphinpyrazone on antipyrine metabolism and urinary excretion of 6-beta-hydroxycortisol.

Sulphinpyrazone decreases the plasma clearance of tolbutamide and S-warfarin and increases the clearance of R-warfarin, theophylline and antipyrine. In order to determine whether sulphinpyrazone is an inducer or inhibitor or both of oxidative drug metabolism, antipyrine and its metabolites as well as 6-beta-hydroxycortisol were measured in urine before, 24 h and after 23 days of chronic administration of sulphinpyrazone (4 X 200 mg/day). During chronic treatment sulphinpyrazone increased the ratio of 6-beta-hydroxycortisol to the 17-hydroxycorticosteroids by 70% (p less than 0.02). The renal clearance of the main oxidative metabolites of antipyrine (4-hydroxyantipyrine, 3-hydroxymethylantipyrine and norantipyrine) were increased after sulphinpyrazone (p less than 0.02). Except for norantipyrine, no change in total excretion of antipyrine and its metabolites occurred after 24 h or after 23 days. It is concluded that sulphinpyrazone induces the enzymes which metabolize antipyrine and cortisol.

Adult↗
PubMed1982

Enhanced drug metabolism after sulfinpyrazone treatment in patients aged 50 to 60 years.

The induction of liver drug metabolism was investigated in five patients before and after the administration of 800 mg sulfinpyrazone daily for 4 weeks, by using antipyrine plasma-pharmacokinetics and by determining urinary excretion of 6-beta-OH-cortisol and serum gamma-glutamyl-transpeptidase (GGT) activity. Antipyrine half-life was shortened in all patients from a mean value of 12.3 +/- 3.9 h to 7.8 +/- 2.0 h and antipyrine clearance was increased from 39.0 +/- 16.0 ml/min to 57.6 +/- 13.7 ml/min. In contrast the volume of distribution of antipyrine was unaffected; the values being 38.0 +/- 8.6 liters and 37.4 +/- 5.7 liters, respectively. In all patients the excretion of 6-beta-OH-cortisol in the urine went up from 65.0 +/- 25.7 micrograms/24 h to 346.8 +/- 193.4 micrograms/24 h. The ratio 6-beta-OH-cortisol/free cortisol changed from 4.1 to 15.8. After 21 days of treatment the GGT increased from 17.4 +/- 4.9 units/liter to 32.6 +/- 12.5 units/liter The data presented confirm that sulfinpyrazone induces drug metabolism in patients of the older age group. Interactions between sulfinpyrazone and other drugs given simultaneously must be borne in mind.

Age Factors↗
PubMed1982

Lack of effect of cimetidine on action of phenprocoumon.

In patients on oral warfarin, nicoumalone and phenindione an increase in the anticoagulant effect has been described during concomitant treatment with cimetidine. Therefore the effect of cimetidine on the steady state dynamics of phenprocoumon has been investigated in ten outpatients. No change in the anticoagulant effect of phenprocoumon was observed during or after two weeks on cimetidine, as measured by the thrombotest coagulation method, prothrombin time, fibrinopeptide A concentration and plasma phenprocoumon level. The data show that cimetidine does not interact with the metabolism of phenprocoumon in contrast to warfarin. Thus, phenprocoumon maintenance therapy when combined with concomitant cimetidine treatment can be considered not to carry an increased risk of haemorrhagic complications.

4-Hydroxycoumarins↗
PubMed1982

Cimetidine does not increase the anticoagulant effect of phenprocoumon.

In patients on oral warfarin, nicoumalone and phenindione an increase of the anticoagulant effect has been described during concomitant treatment with cimetidine. Therefore we have investigated the effect of cimetidine on the steady state dynamics of phenprocoumon in ten outpatients. No changes in the anticoagulant effect and the plasma phenprocoumon levels were observed during and after 2 weeks application of cimetidine. The data show that cimetidine does not interact with the metabolism of phenprocoumon in contrast to warfarin.

4-Hydroxycoumarins↗
PubMed1982

The effects of ampicillin on oral contraceptive steroids in women.

1 Thirteen women taking long term oral contraceptive steroids were studied while taking ampicillin (500 mg three times daily) and compared to a control cycle while not taking ampicillin. 2 There were no significant changes in the plasma concentrations of ethinyloestradiol, levonorgestrel, follicle stimulating hormone or progesterone, although lower concentrations of ethinyloestradiol were noted in two women. 3 We conclude that most patients taking oral contraceptive steroids do not need to take alternative contraceptive precautions while taking ampicillin.

Adult↗
PubMed1981

Induction of drug metabolizing enzymes by sulfinpyrazone.

A previous interaction study of sulfinpyrazone (Anturano) suggested that it induced microsomal drug metabolizing enzymes in the liver. To verify this finding the effect of sulfinpyrazone 800 mg per day for four weeks was investigated in ten healthy volunteers. Both the therapeutic actions of sulfinpyrazone, the uricosuric and the antiaggregating effects, were demonstrated (p less than 0.05). The influence on the microsomal drug metabolizing system in the liver was demonstrated by an increase in serum-gamma-glutamyl transpeptidase from 15.1 to 23.3 U/l (p greater than 0.05), a significant increase in the urinary excretion of d-glucaric acid (29.6 to 77.9 microMol/24 h, p less than 0.05) and an increase in antipyrine clearance from 50.3 ml/min to 83.9 ml/min (p less than 0.05). The possibility of enhancement of drug metabolism during treatment with sulfinpyrazone in combination with other drugs should be kept in mind.

Adult↗