Isovue-250 Disease Interactions

Reports of thyroid storm following the use of iodinated diagnostic agents in patients with hyperthyroidism or with an autonomously functioning thyroid nodule suggest that this additional risk be evaluated in such patients before the use of any contrast medium. Some agents such as ioversol are contraindicated in symptomatic hyperthyroidism.

Administration of radiopaque materials to patients known or suspected of having pheochromocytoma should be performed with extreme caution. If, in the opinion of the physician, the possible benefits of such procedures outweigh the considered risk, the procedures should be performed with the absolute minimum amount of injected radiopaque medium. The blood pressure should be assessed throughout the procedure and measures for treatment of a hypertensive crisis should be available.

Some contrast agents have shown to promote the phenomenon of sickling (blood cell rupture) in individuals who are homozygous for sickle cell disease when administered intravenously or intra- arterially. Caution is advised.

A definite risk exists in the use of intravascular contrast agents in patients who are known to have multiple myeloma. In such cases, anuria has developed resulting in progressive uremia, renal failure and eventually death. Although neither the contrast agent nor dehydration has separately proved to be the cause of anuria in myeloma, it has been speculated that the combination of both may be causative factors. The risk in patients with myeloma is not a contraindication to the procedure; however, partial dehydration in the preparation of these patients for the examination is not recommended since this may predispose to precipitation of myeloma protein in the renal tubules. Myeloma, which occurs most commonly in persons over 40, should be considered before instituting intravascular administration of contrast agents.

The administration of iodinated contrast media may aggravate the symptoms of myasthenia gravis. Caution is advised when using these agents in patients with this condition.

Iodinated contrast media such as ioversol, can cause life-threatening or fatal hypersensitivity reactions including anaphylaxis and anaphylactic shock. Manifestations include respiratory arrest, laryngospasm, bronchospasm, angioedema, and shock. Most severe reactions develop shortly after the start of the injection (e.g. within 1 to 3 minutes), but delayed reactions may occur. There is an increased risk in patients with a history of a previous reaction to contrast agent, and known allergies (i.e., bronchial asthma, drug, or food allergies), and other hypersensitivities. Caution is advised on these patients. Premedication with antihistamines or corticosteroids to avoid or minimize possible allergic reactions may reduce both their incidence and severity.

In patients with advanced renal disease, iodinated contrast media should be used with caution, and only when the need for the examination dictates, since the excretion of the medium may be impaired. Patients with combined renal and hepatic disease, severe hypertension or congestive heart failure, and those with recent renal transplant may present an additional risk.

The possibility of a reaction, including serious, life-threatening, fatal, anaphylactoid or cardiovascular reactions, should always be considered when using iopamidol. Patients at increased risk include those with a history of a previous reaction to a contrast medium, patients with a known sensitivity to iodine per se, and patients with a known clinical hypersensitivity (bronchial asthma, hay fever, and food allergies). Caution and monitoring is advised. Competent personnel and emergency facilities should be available for at least 30 to 60 minutes since severe delayed reactions may occur.

After parenteral administration of a radiopaque agent such as iopamidol, competent personnel and emergency facilities should be available for at least 30 to 60 minutes since severe delayed reactions may occur. Caution should be exercised in hydrating patients with underlying conditions that may be worsened by fluid overload, such as congestive heart failure.

When using iopamidol, preparatory dehydration is dangerous and may contribute to acute renal failure in patients with advanced vascular disease, diabetic patients, and in susceptible nondiabetic patients (often elderly with preexisting renal disease). Patients should be well hydrated prior to and following iopamidol administration.