Iothalamate

INDICATIONS AND USAGE Conray is indicated for use in excretory urography, cerebral angiography, peripheral arteriography, venography, arthrography, direct cholangiography, endoscopic retrograde cholangiopancreatography, contrast enhancement of computed tomographic brain images, cranial computerized angiotomography, intravenous digital subtraction angiography and arterial digital subtraction angiography. Conray may also be used for enhancement of computed tomographic scans performed for detection and evaluation of lesions in the liver, pancreas, kidneys, abdominal aorta, mediastinum, abdominal cavity and retroperitoneal space. Continuous or multiple scans separated by intervals of 1 to 3 seconds during the first 30 to 90 seconds post-injection of the contrast medium (dynamic CT scanning) may provide enhancement of diagnostic significance, and may be of benefit in establishing diagnoses of certain lesions in these sites with greater assurance than is possible with CT alone, and in supplying additional features of the lesions. In other cases, the contrast agent may allow visualization of lesions not seen with CT alone, or may help to define suspicious lesions seen with unenhanced CT (see CLINICAL PHARMACOLOGY ). Subsets of patients in whom delayed body CT scans might be helpful have not been identified. Inconsistent results have been reported and abnormal and normal tissues may be isodense during the time frame used for delayed CT scanning. The risks of such indiscriminate use of contrast media are well known and such use is not recommended. At present, consistent results have been documented using dynamic CT techniques only.

DOSAGE AND ADMINISTRATION Patient Preparation Unless contraindicated, an appropriate laxative is given the night before the examination. Radiographic Technique The radiographic procedure normally employed for cystography and cystourethrography should be employed. A preliminary radiograph is recommended before the contrast agent is administered. Administration Sterile catherization is essential. Cysto-Conray II may be introduced by gravity flow using an appropriate venoclysis set or by syringe. Excessive pressure should be avoided with any method of administration. Usual Dosage Cystography and Cystourethrography – Either Conray 43 supplied at 43% w/v or Cysto-Conray II supplied at a 17.2% w/v concentration may be used for these procedures. The desired concentration will vary depending upon the patient’s size and age and also with the technique and equipment used. (SEE CONRAY 43 PACKAGE INSERT FOR SPECIFIC INFORMATION ABOUT THE USE OF THIS PRODUCT.) Sufficient volume of contrast medium is administered to adequately fill the urinary bladder. The volume of solution required will vary depending upon the individual patient. Adults usually require a volume in the range of 200 to 400 mL. Children require a volume in proportion to their body size. The usual dose ranges from 30 to 300 mL.

WARNINGS 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 ensure that this drug product is not administered intrathecally. 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. Serious or fatal reactions have been associated with the administration of iodine-containing radiopaque media. It is of utmost importance to be completely prepared to treat any contrast medium reaction. Serious neurologic sequelae, including permanent paralysis, have been reported following cerebral arteriography, selective spinal arteriography and arteriography of vessels supplying the spinal cord. The intravascular injection of a contrast medium should never be made following the administration of vasopressors since they strongly potentiate neurologic effects. 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. A definite risk exists in the use of intravascular contrast agents in patients who are known to have multiple myeloma. In such instances, 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 myelomatous patients 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. No form of therapy, including dialysis, has been successful in reversing the effect. Myeloma, which occurs most commonly in persons over 40, should be considered before instituting intravascular administration of contrast agents. 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. Convulsions have occurred in patients with primary or metastatic cerebral lesions following the administration of iodine-containing radiopaque media for the contrast enhancement of CT brain images. In patients with advanced renal disease, iodinated contrast media should be used with caution, and only when the need for the examination dictates, since excretion of the medium may be impaired. Patients with combined renal and hepatic disease, those with severe hypertension or congestive heart failure, and recent renal transplant recipients may present an additional risk. Renal failure has been reported in patients with liver dysfunction who were given an oral cholecystographic agent followed by an intravascular iodinated radiopaque agent, and also in patients with occult renal disease, notably diabetics and hypertensives. In these classes of patients, there should be no fluid restriction and every attempt made to maintain normal hydration, prior to contrast medium administration, since dehydration is the single most important factor influencing further renal impairment. Acute renal failure has been reported in diabetic patients with diabetic nephropathy and in susceptible non-diabetic patients (often elderly with pre-existing renal disease) following the administration of iodinated contrast agents. Therefore, careful consideration of the potential risks should be given before performing this radiographic procedure in these patients. Caution should be exercised in performing contrast medium studies in patients with endotoxemia and/or those with elevated body temperatures. Reports of thyroid storm occurring following the intravascular use of iodinated radiopaque agents in patients with hyperthyroidism or with an autonomously functioning thyroid nodule, suggest that this additional risk be evaluated in such patients before use of this drug. Iodine containing contrast agents may alter the results of thyroid function tests which depend on iodine estimation, e.g. PBI and radioactive iodine uptake studies. Such tests, if indicated, should be performed prior to the administration of this preparation. Thyroid Dysfunction in Pediatric Patients 0 to 3 Years of Age: Thyroid dysfunction characterized by hypothyroidism or transient thyroid suppression has been reported after both single exposure and multiple exposures to iodinated contrast media (ICM) in pediatric patients 0 to 3 years of age. Younger age, very low birth weight, prematurity, underlying medical conditions affecting thyroid function, admission to neonatal or pediatric intensive care units, and congenital cardiac conditions are associated with an increased risk of hypothyroidism after ICM exposure. Pediatric patients with congenital cardiac conditions may be at the greatest risk given that they often require high doses of contrast during invasive cardiac procedures. An underactive thyroid during early life may be harmful for cognitive and neurological development and may require thyroid hormone replacement therapy. After exposure to ICM, individualize thyroid function monitoring based on underlying risk factors, especially in term and preterm neonates. Severe Cutaneous Adverse Reactions: Severe cutaneous adverse reactions (SCAR) may develop from 1 hour to several weeks after intravascular contrast agent administration. These reactions include Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN), acute generalized exanthematous pustulosis (AGEP) and drug reaction with eosinophilia and systemic symptoms (DRESS). Reaction severity may increase and time to onset may decrease with repeat administration of contrast agent; prophylactic medications may not prevent or mitigate severe cutaneous adverse reactions. Avoid administering Conray to patients with a history of a se

CONTRAINDICATIONS Refer to PRECAUTIONS, General, concerning hypersensitivity. Conray should not be used for myelography. Arthrography should not be performed if infection is present in or near the joint. Percutaneous transhepatic cholangiography is contraindicated in patients with coagulation defects and prolonged prothrombin times. Endoscopic retrograde cholangiopancreatography is contraindicated during an acute attack of pancreatitis or during severe clinically evident cholangitis and in patients in whom endoscopy is prohibited.

ADVERSE REACTIONS Adverse reactions to injectable contrast media fall into two categories: chemotoxic reactions and idiosyncratic reactions. Chemotoxic reactions result from the physio-chemical properties of the contrast media, the dose and speed of injection. All hemodynamic disturbances and injuries to organs or vessels perfused by the contrast medium are included in this category. Idiosyncratic reactions include all other reactions. They occur more frequently in patients 20 to 40 years old. Idiosyncratic reactions may or may not be dependent on the amount of dose injected, the speed of injection, the mode of injection and the radiographic procedure. Idiosyncratic reactions are subdivided into minor, intermediate and severe. The minor reactions are self-limited and of short duration; the severe reactions are life-threatening and treatment is urgent and mandatory. Fatalities have been reported following the administration of iodine-containing contrast agents. Based upon clinical literature, the incidence of death is reported to range from one in 10,000 (0.01 percent) to less than one in 100,000 (0.001 percent). The following adverse reactions have been observed in conjunction with the use of iodine-containing contrast agents. The most frequent adverse reactions are nausea, vomiting, facial flush and a feeling of body warmth. These are usually of brief duration. Other reactions include the following: Hypersensitivity reactions: Dermal manifestations of urticaria with or without pruritus, erythema and maculopapular rash. Dry mouth. Sweating. Conjunctival symptoms. Facial, peripheral and angioneurotic edema. Symptoms related to the respiratory system include sneezing, nasal stuffiness, coughing, choking, dyspnea, chest tightness and wheezing, which may be initial manifestations of more severe and infrequent reactions including asthmatic attack, laryngospasm and bronchospasm with or without edema, pulmonary edema, apnea and cyanosis. Rarely, these allergic-type reactions can progress into anaphylaxis with loss of consciousness and coma and severe cardiovascular disturbances. Cardiovascular reactions: Generalized vasodilation, flushing and venospasm. Occasionally, thrombosis or rarely, thrombophlebitis. Red blood cell clumping and agglutination, crenation and interference in clot formation. Extremely rare cases of disseminated intravascular coagulation resulting in death have been reported. Severe cardiovascular responses include rare cases of hypotensive shock, coronary insufficiency, cardiac arrhythmia, fibrillation and arrest. These severe reactions are usually reversible with prompt and appropriate management; however, fatalities have occurred. Endocrine reactions: Hyperthyroidism, hypothyroidism. Skin and Subcutaneous Tissue Disorders: Reactions range from mild (e.g. rash, erythema, pruritus, urticaria and skin discoloration) to severe: [e.g. Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN), acute generalized exanthematous pustulosis (AGEP) and drug reaction with eosinophilia and systemic symptoms (DRESS)]. Technique reactions: Extravasation with burning pain, hematomas, ecchymosis and tissue necrosis, paresthesia or numbness, vascular constriction due to injection rate, thrombosis and thrombophlebitis. Neurological reactions: Spasm, convulsions, aphasia, syncope, paresis, paralysis resulting from spinal cord injury and pathology associated with syndrome of transverse myelitis, visual field losses which are usually transient but may be permanent, coma and death. Other reactions: Headache, trembling, shaking, chills without fever and lightheadedness. Temporary renal shutdown or other nephropathy. (Adverse reactions to specific procedures receive comment under that procedure.)

CLINICAL PHARMACOLOGY Following intravascular injection, Conray is rapidly transported through the circulatory system to the kidneys and is excreted unchanged in the urine by glomerular filtration. The pharmacokinetics of intravascularly administered radiopaque contrast media are usually best described by a two compartment model with a rapid alpha phase for drug distribution and a slower beta phase for drug elimination. In patients with normal renal function, the alpha and beta half-lives of Conray were approximately 10 and 90 minutes, respectively. Angiography may be performed following intravascular injection which will permit visualization until significant hemodilution occurs. Renal accumulation is sufficiently rapid that maximum radiographic density in the calyces and pelves occurs, in most instances, about 3 to 8 minutes after injection. In patients with impaired renal function, diagnostic opacification frequently is achieved only after prolonged periods. Injectable iodinated contrast agents are excreted either through the kidneys or through the liver. These two excretory pathways are not mutually exclusive, but the main route of excretion seems to be related to the affinity of the contrast medium for serum albumin. Iothalamate salts are poorly bound to serum albumin, and are excreted mainly through the kidneys. The liver and small intestine provide the major alternate route of excretion. In patients with severe renal impairment, the excretion of this contrast medium through the gallbladder and into the small intestine sharply increases. Iothalamate salts cross the placental barrier in humans and are excreted unchanged in human milk. The biliary system, pancreatic duct or joint spaces may be visualized by the direct injection of contrast medium into the region to be studied. CT Scanning of the Head When used for contrast enhancement in computed tomographic brain scanning, the degree of enhancement is directly related to the amount of iodine administered. Rapid injection of the entire dose yields peak blood iodine concentrations immediately following the injection, which fall rapidly over the next five to ten minutes. This can be accounted for by the dilution in the vascular and extracellular fluid compartments which causes an initial sharp fall in plasma concentration. Equilibration with the extracellular compartments is reached by about ten minutes; thereafter, the fall becomes exponential. Maximum contrast enhancement frequently occurs after peak blood iodine levels are reached. The delay in maximum contrast enhancement can range from five to forty minutes, depending on the peak iodine levels achieved and the cell type of the lesion. This lag suggests that the contrast enhancement of the image is at least in part dependent on the accumulation of iodine within the lesion and outside the blood pool. In brain scanning, the contrast medium (Conray) does not accumulate in normal brain tissue due to the presence of the “blood brain barrier.” The increase in x-ray absorption in the normal brain is due to the presence of the contrast agent within the blood pool. A break in the blood brain barrier, such as occurs in malignant tumors of the brain, allows accumulation of contrast medium within the interstitial tumor tissue; adjacent normal brain tissue does not contain the contrast medium. The image enhancement of non-tumoral lesions, such as arteriovenous malformations and aneurysms, is dependent on the iodine content of the circulating blood pool. When used for cranial computerized angiotomography, rapid bolus injection and/or infusion combined with rapid CT scanning will provide clear delineation of the cerebral vessels. CT Scanning of the Body 1 In non-neural tissues (during CT of the body), Conray diffuses rapidly from the vascular to the extra-vascular space. Increase in x-ray absorption is related to blood flow, concentration of the contrast medium and extraction of the contrast medium by interstitial tissue, since no barrier exists; contrast enhancement is thus due to the relative differences in extra-vascular diffusion between normal and abnormal tissue, a situation quite different than that in the brain. The pharmacokinetics of Conray in normal and abnormal tissues has been shown to be variable. Enhancement of CT with Conray may be of benefit in establishing diagnoses of certain lesions in some sites with greater assurance than is possible with unenhanced CT and in supplying additional features of the lesions. In other cases, the contrast medium may allow visualization of lesions not seen with CT alone or may help to define suspicious lesions seen with unenhanced CT. Contrast enhancement appears to be greatest within the 30 to 90 seconds after bolus administration of the contrast agent, and after intra-arterial, rather than intravenous, administration. Therefore, the use of a continuous scanning technique (a series of 2 to 3 second scans beginning at the injection - dynamic CT scanning) may improve enhancement and diagnostic assessment of tumors and other lesions, such as an abscess, occasionally revealing more extensive disease. A cyst, or similar non-vascularized lesion, may be distinguished from vascularized solid lesions by comparing enhanced and unenhanced scans; non-vascularized lesions show no change in CT number, whereas vascularized lesions would show an increase. The latter might be benign, malignant or normal, but it is unlikely that it would be a cyst, hematoma, or other non-vascularized lesion. Because unenhanced scanning may provide adequate information in the individual patient, the decision to employ contrast enhancement, which is associated with additional risk and increased exposure, should be based upon a careful evaluation of clinical, other radiological, and unenhanced CT findings.