A recently marketed prolonged-release quinidine gluconate tablet was compared with the innovator's tablet in a single-dose bioavailability study with 12 healthy male subjects. The extent of absorption of quinidine from the new marketed product was only 50 per cent of the innovator's product. This finding, as well as projections of steady-state plasma concentrations to be expected during multiple-dose administration, indicated a bioequivalence problem with medically significant implications. The data obtained in this study resulted in a Class I recall of the less completely absorbed product by the U.S. Food and Drug Administration.

Adult↗

PubMedDate not supplied

Anaphylactoid reactions to radiocontrast material.

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Adult↗

PubMedDate not supplied

Safe fixation of oro- or nasotracheal tubes for prolonged intubation in neonates, infants and children.

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Child↗

PubMedDate not supplied

Measurement of histamine, complement components and immune complexes during patient reactions to iodinated contrast material.

Studies were performed on nine patients who had just suffered urticarial or bronchospastic reactions following injection of iodinated contrast material (ICM). The parameters studied were white cell histamine, serum complement components C'3 and C'4 and circulating immune complexes. The white cells of the nine patients demonstrated an average increase of 125% in intracellular histamine over the 3-4 week period following the ICM reaction. Control volunteers averaged only a 10% change. The data implies that there was a loss of white cell histamine during the ICM reaction with replenishment during the following 3-4 week period. Complement components C'3 and C'4 were normal. Circulating antigen-antibody complexes were sought via precipitin bands in agar gel using Clq. None could be isolated following seven ICM reactions. Thus these ICM reactions appeared to release histamine without detection of circulating immune complexes and with normal levels of two major complement components.

Antigen-Antibody Complex↗

PubMedDate not supplied

Administration of radiographic contrast media in high-risk patients.

Patients with a prior history of an anaphylactoid reaction (AR) to radiographic contrast media (RCM) have an increased risk of an AR during subsequent RCM studies. Based on previous studies in high-risk patients using prednisone or diphenhydramine to reduce the incidence of AR, high-risk patients were treated with a combined prednisone and diphenhydramine protocol in an effort to develop an effective, practical approach to this problem. All patients with convincing histories of AR to RCM with an essential need for a repeat RCM study received 50 mg of prednisone orally every 6 hours for 3 doses ending 1 hour before the RCM study, and 50 mg of diphenhydramine intramuscularly 1 hour prior to the procedure. Resuscitation equipment was readily available. One hundred forty-seven repeat procedures using RCM were carried out in 142 high-risk patients. No serious AR occurred. Two patients had generalized urticaria that resolved in 1 hour. The overall reaction rate in these pretreated high-risk patients was 6.8%, suggesting that this prednisone-diphenhydramine program may be the preferred prophylactic regimen when repeat RCM studies are necessary.

Anaphylaxis↗

PubMedDate not supplied

In vitro complement consumption by contrast materials and analogues: reactors vs. nonreactors.

Blood samples from previous contrast reactors and nonreactor controls were incubated with diatrizoate and several contrast analogues. Total complement levels were assayed. All the agents caused complement activation generally proportional to their concentration. Reactors' sera responded to lower concentrations of contrast or analogues than did control sera. Such studies might be of value in predicting contrast reactors.

Acetamides↗

PubMedDate not supplied

Increased urine histamine and contrast media reactions.

Urine samples were collected from 200 subjects undergoing intravenous pyelography. The urine histamine levels were compared with those of 132 normal control subjects, 11 subjects with systemic mastocytosis, six subjects with idiopathic anaphylaxis, and ten subjects experiencing mild anaphylactic reactions during allergy immunotherapy. Compared with normal controls, as a group, all subjects receiving intravenous contrast media had increased urine histamine (P less than 0.05 by Student's t-test) while those subjects experiencing adverse reactions had considerably larger increases. The urine histamine levels in the subjects experiencing systemic reactions were in the same range as those observed in patients having mild anaphylactic reactions to immunotherapy and somewhat lower than those found in idiopathic anaphylaxis or systemic mastocytosis. These data suggest that some histamine release accompanies infusions of contrast media in all subjects and that larger amounts of histamine release are associated with adverse reactions.

Adolescent↗