Biomedical subjects

D D Shaw

Publications and source records attributed to D D Shaw.

41 records · Page 3Linked to original sources

PubMedDate not supplied

Summary of U.S. and European intravascular experience with iohexol based on the clinical trial program.

The nonionic contrast medium, iohexol, was released by Nyegaard, Oslo, in 1980 for clinical testing. Results of a three-phase clinical trial program carried out in Europe and the U.S. through December 1983 are summarized. Evaluation of phase I studies of human tolerance and excretion--and phase II studies of effects on pharmacologic and physiologic parameters--indicated that iohexol was well tolerated and effective. Phase III consisted mainly of controlled parallel and crossover studies comparing iohexol with conventional ionic media and with other nonionic agents in a variety of radiographic studies. Image quality was as good or better with iohexol than with ionic media. Iohexol was tolerated significantly better than ionic agents. Patients consistently reported fewer and less intense pain and heat sensations. Iohexol had less effect on blood pressure, blood flow, heart rate, and electrophysiologic parameters, and caused fewer adverse reactions than ionic media for all types of reactions observed.

Clinical Trials as Topic↗

PubMedDate not supplied

Iohexol: summary of North American and European clinical trials in adult lumbar, thoracic, and cervical myelography with a new nonionic contrast medium.

Iohexol, a new water-soluble nonionic contrast medium, was evaluated in clinical trials in Europe and North America for lumbar, thoracic, and cervical myelography using direct C1-2 or lumbar puncture. Iohexol was administered at 180, 240, or 300 mg I/ml to 677 adult patients for visualization of the lumbar subarachnoid space, and to 368 adult patients for evaluation of the cervical area. Compared with metrizamide, use of iohexol resulted in equivalent opacification but significantly reduced patient morbidity (headache, nausea, vomiting, dizziness). No epileptogenic activity was recorded in over 370 patients receiving iohexol. No mental or psycho-organic syndrome manifestations were observed in any of the 1,045 patients receiving iohexol. Adverse reactions occurring after iohexol injection were not related to the concentration or site used or to total dose administered. Iohexol has, thus far, proven superior to metrizamide for myelography.

Adult↗

PubMedDate not supplied

Iohexol for cervical myelography via C1-C2 puncture: study of efficacy and adverse reactions.

Cervical myelography with iohexol via C1-C2 puncture was performed in 30 patients in two medical centers using a concentration of 240 mg l/ml. The study demonstrated iohexol to be a safe contrast medium without significant changes in neurologic and physical examination, vital signs, electrocardiogram, or hematologic or blood chemistry parameters. Fifteen patients had electroencephalograms (EEGs); two were abnormal. In one patient the baseline EEG demonstrated nonspecific slow waves in the temporal regions bilaterally that remained unchanged after myelography. In the second patient, transient changes in the left hemisphere during either hyperventilation or photic stimulation on postmyelographic EEG had not been present on the baseline recording. The relation of these changes to the drug remains unclear. Iohexol was found to be an efficacious myelographic contrast agent, with good to excellent myelograms in 93% of cases. Headache occurred in 13% and nausea in 3%.

Adult↗

PubMedDate not supplied

Iohexol vs. metrizamide: study of efficacy and morbidity in cervical myelography.

A double-blind study was conducted in 60 patients undergoing either cervical or more complete myelography via C1-C2 puncture. Patients received either iohexol or metrizamide at a 300 mg l/ml concentration. The contrast media were equally efficacious in the production of high-quality radiographs and CT scans. However, the incidence of adverse reactions differed markedly. Of patients receiving metrizamide, 68% had some type of adverse reaction, whereas only 26% receiving iohexol had symptoms. The incidence of headache (metrizamide, 34%; iohexol, 26%) was not statistically different, but the quality of the headache differed: half of the metrizamide headaches were moderate or severe, whereas all iohexol headaches were mild. Nausea (31%) and vomiting (28%) were common with metrizamide but unusual (3% nausea) with iohexol. Of the metrizamide patients, 21% had overt psychologic changes that did not occur in the iohexol group.

Adult↗

PubMedDate not supplied

Metrizamide, iothalamate, and metrizoate: effects of internal carotid arterial injections on the blood-brain barrier of the rabbit.

Experiments were conducted on anesthetized rabbits to determine the effect of internal carotid artery injection of various contrast media on permeability changes in the blood-brain barrier. Changes in respiratory pattern, neuromuscular effects, and trypan blue extravasation were recorded after 3-ml injections of ionic and nonionic contrast media. Metrizamide and iothalamate meglumine were compared at iodine doses of 300, 400, and 500 mg I/ml. Metrizoate at 280 and 440 mg I/ml and diatrizoate meglumine at 385 mg I/ml were also included for comparison. The results demonstrated that metrizamide at all three iodine concentrations used caused minimal disruption of the blood-brain barrier, the effect being no greater, statistically, than saline controls. Iothalamate was benign at the lowest iodine concentration, but caused significant barrier breakdown at the two higher concentrations. These results suggest that alterations in blood-brain barrier permeability following angiography are mediated by both hyperosmolality of the contrast medium and the chemotoxicity of the contrast molecule.

Animals↗