Severe Adverse Events—Inadvertent Intrathecal Administration
Serious adverse reactions have been reported due to the inadvertent intrathecal administration of iodinated contrast media that are not indicated for intrathecal use. These serious adverse reactions include: death, convulsions, cerebral hemorrhage, coma, paralysis, arachnoiditis, acute renal failure, cardiac arrest, seizures, rhabdomyolysis, hyperthermia, and brain edema. Special attention must be given to insure that this drug product is not inadvertentlyadministered intrathecally.
The possibility exists for inadvertent administration into the intrathecal space during epidural administrations. Therefore, epidural administration procedures, such as pain management catheter placement, should not be performed with use of this product.
Ionic iodinated contrast media inhibit blood coagulation, in vitro, more than nonionic contrast media. Nonetheless, it is prudent to avoid prolonged contact of blood with syringes containing ionic contrast media.
Serious, rarely fatal, thromboembolic events causing myocardial infarction and stroke have been reported during angiographic procedures with both ionic and nonionic contrast media. Therefore, meticulous intravascular administration technique is necessary, particularly during angiographic procedures, to minimize thromboembolic events. Numerous factors, including length of procedure, catheter and syringe material, underlying disease state, and concomitant medications may contribute to the development of thromboembolic events. For these reasons, meticulous angiographic techniques are recommended including close attention to guidewire and catheter manipulation, use of manifold systems and/or three way stopcocks, frequent catheter flushing with heparinized saline solutions, and minimizing the length of the procedure. The use of plastic syringes in place of glass syringes has been reported to decrease but not eliminate the likelihood of in vitro clotting.
A definite risk exists in the use of intravascular contrast agents in patients who are known to have multiple myeloma. In such instances there has been anuria 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 the causative factor. The risk in myelomatous patients is not a contraindication to the procedures; however, partial dehydration in the preparation of these patients for the examination is not recommended since this may predispose to the precipitation of myeloma protein in the renal tubules. No form of therapy, including dialysis, has been successful in reversing this effect. Myeloma, which occurs most commonly in persons over age 40, should be considered before intravascular administration of a contrast agent.
Administration of radiopaque materials to patients known or suspected to have pheochromocytoma should be performed with extreme caution. If, in the opinion of the physician, the possible benefits of such procedures outweigh the considered risks, the procedures may be performed; however, the amount of radiopaque medium injected should be kept to an absolute minimum. The blood pressure should be assessed throughout the procedure and measures for treatment of a hypertensive crisis should be available.
Contrast media have been shown to promote the phenomenon of sickling in individuals who are homozygous for sickle cell disease when the material is injected intravenously or intra-arterially.
Since iodine-containing contrast agents may alter the results of thyroid function tests, such tests, if indicated, should be performed prior to the administration of this preparation.
A history of sensitivity to iodine per se or to other contrast agents is not an absolute contraindication to the use of diatrizoate, but calls for extreme caution in administration.
In patients with subarachnoid hemorrhage, a rare association between contrast administration and clinical deterioration, including convulsions and death, has been reported; therefore, administration of intravascular iodinated ionic contrast media in these patients should be undertaken with caution.
The inherent risks of angiocardiography in cyanotic infants and patients with chronic pulmonary emphysema must be weighed against the necessity for performing this procedure. In pediatric angiocardiography, a dose of 10 to 20 mL may be particularly hazardous in infants weighing less than 7 kg. This risk is probably significantly increased if these infants have preexisting right heart“strain,” right heart failure, and effectively decreased or obliterated pulmonary vascular beds.
Urography and nephrotomography should be performed with extreme caution in patients with severe concomitant hepatic and renal disease.
Selective visceral arteriography should be performed with extreme caution in patients with severe generalized atherosclerosis, specifically with plaques or aneurysms at the level of the iliac or femoral arteries.
Selective coronary arteriography should be performed only in selected patients and those in whom the expected benefits outweigh the procedural risk.
Diagnostic procedures which involve the use of diagnostic radiopaque contrast agents should be carried out under the direction of personnel with the prerequisite training and with a thorough knowledge of the particular procedure to be performed. Appropriate facilities should be available for coping with any complication of the procedure, as well as for emergency treatment of severe reactions to the contrast agent itself. After parenteral administration of a radiopaque agent, competent personnel and emergency facilities should be available for at least 30 to 60 minutes since severe delayed reactions have occurred (see ADVERSE REACTIONS).
Severe, life-threatening reactions suggest hypersensitivity to the radiopaque agent, which has prompted the use of several pretesting methods, none of which can be relied upon to predict severe reactions. Many authorities question the value of any pretest. A history of bronchial asthma or allergy, a family history of allergy, or a previous reaction to a contrast agent warrant special attention. Such a history, by suggesting histamine sensitivity and a consequent proneness to reactions, may be more accurate than pretesting in predicting the likelihood of a reaction, although not necessarily the severity or type of reaction in the individual case.
The sensitivity test most often performed is the slow injection of 0.5 to 1.0 mL of the radiopaque medium, administered intravenously, prior to injection of the full diagnostic dose. It should be noted that the absence of a reaction to the test dose does not preclude the possibility of a reaction to the full diagnostic dose. If the test dose causes an untoward response of any kind, the necessity for continuing with the examination should be carefully reevaluated and, if it is deemed essential, the examination should be conducted with all possible caution. In rare instances reactions to the test dose itself may be extremely severe; therefore, close observation of the patient, and facilities for emergency treatment, appear indicated.
Renal toxicity has been reported in a few patients with liver dysfunction who were given oral cholecystographic agents followed by urographic agents. Administration of RenoCal-76 (Diatrizoate Meglumine and Diatrizoate Sodium Injection USP) should therefore be postponed in any patient with a known or suspected hepatic or biliary disorder who has recently taken a cholecystographic contrast agent.
Caution should be exercised with the use of radiopaque media in severely debilitated patients and in those with marked hypertension. The possibility of thrombosis should be borne in mind when percutaneous techniques are employed.
Consideration must be given to the functional ability of the kidneys before injecting this preparation.
Contrast agents may interfere with some chemical determinations made on urine specimens; therefore, urine should be collected before administration of the contrast medium or two or more days afterwards.
The following precautions pertain to specific procedures:
Excretion urography and nephrotomography: Acute renal failure has been reported in diabetic patients with diabetic nephropathy and susceptible nondiabetic patients (often elderly with preexisting renal disease) following urographic procedures. Therefore, careful consideration should be given to the increased potential risk in these patients prior to performing either procedure. In excretion urography adequate visualization may be difficult or impossible to attain in uremic patients or others with severely impaired renal function (see CONTRAINDICATIONS). In nephrotomography, although azotemia is not considered a contraindication, care is required in patients with advanced renal failure. Preparatory partial dehydration is not recommended in these patients, and their urinary output should be observed for one to two days following the procedure.
Aortography: Repeated intra-aortic injections may be hazardous.
Pediatric angiocardiography: Repeated injections may be hazardous particularly in infants weighing less than 7 kg (see WARNINGS).
Peripheral arteriography: Hypotension or moderate decreases in blood pressure seem to occur frequently with intra-arterial (brachial) injections; therefore, the blood pressure should be monitored during the immediate ten minutes after injection; this blood pressure change is transient and usually requires no treatment.
Selective coronary arteriography: It is recommended that the procedure should not be performed for approximately four weeks following the diagnosis of myocardial infarction. Mandatory prerequisites to the procedure are experienced personnel, ECG monitoring apparatus, and adequate facilities for immediate resuscitation and cardioversion.
Intravenous digital subtraction angiography: The dose is usually administered mechanically under high pressure; rupture of smaller peripheral veins can occur. This may be avoided by using an intravenous catheter threaded proximally beyond larger tributaries or, in the case of the antecubital vein, into the superior vena cava; the femoral vein is used sometimes. It may be desirable to administer a test dose by manual injection prior to the diagnostic dose to ensure that the catheter has been properly positioned.
Usage In Pregnancy
Safety for use during pregnancy has not been established; therefore, this preparation should be used in pregnant patients only when, in the judgment of the physician, its use is deemed essential to the welfare of the patient.