Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: KEGG:D01817 (Iohexol)
 504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of adding NaCl to the non-ionic contrast medium iohexol (Omnipaque) were investigated in the isolated rat heart. Iohexol (150 mgI/ml) with 0, 10, 20, 30, 50, 145 mM NaCl added and the ionic dimeric compound ioxaglate (Hexabrix 160 mgI/ml) containing approximately 75 mM NaCl were examined. Coronary flow rate (CFR), heart rate (HR), left ventricular developed pressure (LVDP) and myocardial high energy phosphate compounds at the end of the experiments were measured. In all groups examined the physiological changes following contrast media injection were only transient and the recovery to normal values of HR and LVDP occurred within 30 seconds. The contractile changes after contrast media exposure were dependent on the concentration of sodium added. The addition of 20 mM sodium to iohexol induced the least changes in LVDP. It is concluded from the present study that addition of sodium in the range of 20-40 mM to non-ionic contrast media, may reduce the immediate cardiac disturbances during coronary angiography.
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PMID:Effects of low osmolar contrast media on cardiac function: optimal sodium concentration for contractility. 186 5

The effects of three low-osmolar radiographic contrast media (CM)--two nonionic (iohexol, iopamidol) and one ionic (ioxaglate)--on red blood cell (RBC) morphology and aggregation behavior, as well as on blood and plasma viscosity, have been studied. Blood taken from normal, healthy individuals and from patients with uremia was investigated. The authors controlled for the effects of dilution, ionic and nonionic hyperosomolality, and specific chemotoxicity. With ioxaglate, the normal biconcave RBC morphology was fairly well maintained. Iohexol produced a mixture of more-or-less normal cells and echinocytes, while iopamidol yielded only echinocytes. Irregular RBC aggregates have been frequently associated with the presence of echinocyte morphology. In the case of ioxaglate, the capacity of normal blood for rouleaux formation was preserved. This appeared to be compatible with an only moderate decrease in low shear viscosity values. In comparison to the normal control group, RBCs from patients with uremia were clearly more sensitive for hyperosmolar stress. It can be concluded that, in contrast to the nonionic CM, the ionic dimeric compound ioxaglate seems to protect human RBCs against hyperosmolar stress by a mechanism unknown at the present.
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PMID:The effect of low-osmolar ionic and nonionic contrast media on human blood viscosity, erythrocyte morphology, and aggregation behavior. 193 91

The chemistry of low-osmolality contrast agents is reviewed, the effects of these agents on vascular and organ physiology are compared with the effects of conventional ionic contrast media, and guidelines for intravascular use of the low-osmolality agents in selected high-risk patients are presented. Three low-osmolality contrast agents, the nonionic media iohexol (Omnipaque, Winthrop-Breon) and iopamidol (Isovue, Squibb) and the dimeric medium ioxaglate meglumine-sodium (Hexabrix, Mallinckrodt) have recently been introduced into the contrast-media market. Compared with conventional ionic contrast media, these new agents demonstrate approximately one third of the osmolality per given iodine concentration (degree of roentgenographic opacification). Therefore, the risks of hyperosmolarity-induced reactions to contrast media are lower with the new agents. The low-osmolality agents may be associated with a reduced incidence of contrast-media-induced hypersensitivity reactions. Because of their lower osmolality, these agents produce less vessel dilation, vascular endothelial damage, and associated pain and discomfort than equi-iodine concentrations of the conventional ionic media. They also demonstrate a reduction in the incidence and severity of contrast-media-induced renal vasoconstriction and proteinuria, hemodynamic alterations, negative chronotropic effects, depression of myocardial contractility, and neurotoxicity in the presence of an altered blood-brain barrier. These low-osmolality agents produce fewer undesirable physiological effects than conventional contrast agents, but the cost of the new products can be more than 10 times as great. Therefore, the new products should be used selectively in patients known to be at increased risk for reactions to intravascular contrast media. A scoring system was developed to permit rapid recognition of documented single or multiple risk factors and subsequent determination of whether to administer a low-osmolality agent.
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PMID:Evaluation of intravascular low-osmolality contrast agents. 378 Jan 59

Effects in cardioangiography from injections into the right atrium of rabbits of two new contrast media of low osmolality, one non-ionic (iohexol) and one ionic dimeric (ioxaglate), were recorded and compared with a currently used ionic contrast medium (metrizoate) of high osmolality. Iohexol and ioxaglate produced significantly smaller increase in pulmonary arterial pressure than metrizoate. Also in aortic pressure iohexol and ioxaglate induced smaller changes (compared with the injection of the same volume of saline) than metrizoate.
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PMID:Aortic and pulmonary arterial pressure after injection of contrast media into the right atrium of the rabbit. Comparison between metrizoate, ioxaglate and iohexol. 626 91

Iodixanol (Visipaque) and iohexol (Omnipaque) are dimeric and monomeric, respectively, non-ionic X-ray contrast media (CM), with well-characterized pharmacokinetics in healthy volunteers. This study was undertaken to study the pharmacokinetics of the contrast media in patients with severely impaired renal function. A total of 16 patients referred for preoperative abdominal angiography were randomized to form two groups of eight patients, receiving either iodixanol 320 mgI ml-1 or iohexol 350 mgI ml-1. Urine and faeces were sampled before the examination and collected quantitatively for five days afterwards, and blood samples were drawn frequently. The concentrations of iodine and contrast medium in urine and in serum, and the amount of iodine in faeces were determined. Mean baseline creatinine clearance was 13.6 and 9.9 ml min-1 1.73 m-2 in the iodixanol and iohexol groups, respectively. Patients in the iodixanol group received on average 0.34 gI per kg bodyweight (bw) and those in the iohexol group 0.39 gI per kg bw. The semilogarithmic plots of serum concentration of CM vs. time indicated elimination according to a two-compartment model. The mean elimination half-life was 23.0 h for iodixanol and 27.2 h for iohexol, and the mean apparent volume of distribution was similar for the two CM, ranging from 0.20 to 0.30 1 per kg bw. Mean plasma clearance of iodixanol was 10.4 ml min-1 1.73 m-2 and 6.9 ml min-1 1.73 m-2 for iohexol, whereas the mean renal clearances were 8.7 and 6.1 ml min-1 1.73 m-2, respectively. Mean faecal recovery was 8.2% for iodixanol and 6.1% for iohexol, and the respective figures for that in urine were 76.1 and 74.8%. Renal clearance of radiolabelled iothalamate, a marker of glomerular filtration rate (GFR), measured simultaneously, indicated that both CM were eliminated by the kidneys by glomerular filtration only. Thus, both media are suitable as GFR markers.
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PMID:Elimination of the non-ionic X-ray contrast media iodixanol and iohexol in patients with severely impaired renal function. 756 37

The neural tolerance of the new non-ionic dimer iodixanol was compared with that of the clinically used monomer iohexol and the dimer iotrolan. Behaviour of non-anaesthetised rabbits was monitored for 3 hours after intracisternal injection, at a dose-volume of 1 ml/kg of iodixanol 150 mg I/ml, iodixanol 320 mg I/ml, iohexol 350 mg I/ml, or iotrolan 300 mg I/ml (10 rabbits in each group). Iotrolan induced generalized seizures in 5 rabbits, iodixanol 320 mg I/ml in 2 rabbits, and iodixanol 150 mg I/ml in one rabbit. No excitative changes were observed in rabbits, iodixanol 320 mg I/ml in 2 rabbits, and iodixanol 150 mg I/ml in one rabbit. No excitative changes were observed in rabbits injected with iohexol, but compared with the dimeric contrast media the difference was not significant. Iohexol produced significantly more severe depressive changes than iodixanol 150 mg I/ml (p < 0.01), iodixanol 320 mg I/ml (p < 0.05), and iotrolan 300 mg I/ml (p < 0.05). The results indicate that the excitative neurotoxic potential of the dimer iodixanol is likely to be lower than that of the clinically used dimer iotrolan, but slightly higher than that of iohexol. It may be expected that both dimers will produce a lower frequency of minor neurological adverse reactions than iohexol.
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PMID:CNS-effects from subarachnoid injections of iohexol and the non-ionic dimers iodixanol and iotrolan in the rabbit. 774 28

Iodixanol, the radiopaque in Visipaque, is a new nonionic, dimeric roentgen contrast medium for intravascualr use. Compared to aqueous solutions of nonionic monomers, which have higher osmolality than blood, aqueous solutions of iodixanol have a lower osmolality due to dimeric structure of the molecule. As a consequence of this advantageous property, solutions of all clinical concentrations of iodixanol can be made isotonic by the addition of salts of the key electrolytes sodium and calcium to the formulation. The viscosity of all iodixanol (Visipaque) solutions is less than or equal to that of iohexol (Omnipaque) 350 mg I/ml. Iodixanol itself is an amorphorus and hygroscopic solid which is freely soluble in water. Partition coefficients show that iodixanol is even more hydrophilic than the nonionic monomers such as iohexol. The high hydrophilicity and the good aqueous solubility of iodixanol are due to the hydroxyl group in the dimer linkage and the hydrophilic amide side chains of the molecule.
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PMID:Physicochemical properties of iodixanol. 861 May 27

The renal effects of the new dimeric non-ionic contrast medium Visipaque were investigated in healthy volunteers and in patients with severe renal failure. Visipaque caused no changes in GFR after i.v. injections to healthy volunteers and less changes in tubular function than monomeric CM. Small and transient changes in GFR were observed in predialytic patients both with Visipaque and with the monomeric Omnipaque. A delayed excretion of both CM was observed in these patients and no differences were observed between the two CM as far as tubular enzymes excretion and glomerular functional parameters are concerned. More iodine was retained in the kidney after Visipaque than after monomers, but this was not correlated with changes in tubular parameters and in GFR. Thus, Visipaque was well tolerated in subjects with normal renal function and in patients with severe renal failure.
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PMID:Renal experience with Visipaque. 879 51

1. We have used rings of rabbit thoracic aorta to investigate the vasorelaxant properties of two different classes of non-ionic iodinated radiographic contrast media (IRCM) and the mechanisms, underlying their mode of action. Iohexol (a triiodinated monomer) was compared with iodixanol (a hexaiodinated dimer). 2. Iohexol and iodixanol both relaxed phenylephrine (0.3 microM) constricted rabbit aorta in a concentration-dependent manner that did not depend on the presence of an intact endothelium. When expressed as a function of iodine concentration, iodixanol caused significantly less relaxation than iohexol. However, the extent of relaxation was similar for both IRCM when expressed on a molar basis. Furthermore, increasing the molarity of the buffer to comparable levels with mannitol evoked only a small (approximately 15%) relaxation of phenylephrine-induced tone. 3. Ouabain (10 microM) significantly inhibited both iohexol- and iodixanol-induced relaxations by approximately 30%. 5-(N-Ethyl-N-isopropyl)-amiloride (EIPA, 100 nM) significantly inhibited iohexol-induced relaxation to the same extent as ouabain, but did not alter the vasorelaxant effect of iodixanol. Co-incubation with ouabain and EIPA had an additive effect in the case of iohexol, increasing inhibition of relaxation to approximately 60%, whereas inhibition of iodixanol-induced relaxation by the combination of ouabain plus EIPA did not differ from that of ouabain alone. 4. Replacing NaCl with N-methyl-D-glucamine (NMDG) to lower extracellular [Na+] and thereby inhibit Na(+)-Ca2+ exchange, attenuated the relaxation evoked by iohexol or by iodixanol (by approximately 25%) in each case. 5. We conclude that iohexol- and iodixanol-induced vasorelaxation in rabbit aorta is mediated through a direct action on vascular smooth muscle that is not simply a consequence of altered osmolality. It involves modulation of the Na(+)-K+ ATPase and, in the case of iohexol, Na(+)-H+ exchange. Both agents also appear to modulate Na(+)-Ca2+ exchange, through direct and/or indirect mechanisms. This is the first study to show specific pharmacological differences between monomeric and dimeric contrast media in vascular smooth muscle.
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PMID:Ionic mechanisms contributing to the vasorelaxant properties of iodinated contrast media: a comparison of iohexol and iodixanol in the rabbit isolated aorta. 890 42

A double-blind, randomized phase III study compared intravenous urography in 100 adult patients receiving iodixanol 320 mgI ml-1 (Visipaque) with 99 patients receiving iohexol 350 mgI ml-1 (Omnipaque). The aim of the study was to investigate differences in image quality between a non-ionic dimeric contrast medium (CM) and a non-ionic monomer at 40 ml per patient and 60-100 ml per patient volume levels. There were no statistically significant differences between iodixanol and iohexol with respect to overall diagnostic information, which was found to be optimal in 86% and 79%, respectively. Immediately after the injection, the renal border was better delineated with iohexol than with iodixanol (p = 0.0001). Marked papillary blush occurred more often in the iodixanol group (16%) than in the iohexol group (0%), as did visualization of the collecting ducts (24% vs 5%) (p = 0.001). The incidence of adverse events was similar and low for both contrast media. In patients who received the higher doses of CM (60-100 ml), the frequency of discomfort was significantly lower after iodixanol than after iohexol (p = 0.006). We conclude that, in intravenous urography, iodixanol provides at least as good image quality as does iohexol. Iodixanol may cause less discomfort than iohexol, in particular when larger volumes of CM are injected.
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PMID:Image quality and safety after iodixanol in intravenous urography; a comparison with iohexol. 894 70


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