Optiray Special Precautions

GENERAL: All procedures utilizing contrast media carry a definite risk of producing severe, life threatening and fatal reactions. Therefore, the need for the examination should always be carefully assessed and the risk-benefit factor should always be carefully evaluated before such a procedure is undertaken.
At all times a fully equipped emergency cart, or equivalent supplies and equipment, and personnel competent in recognizing and treating adverse reactions of all severity, or situations which may arise as a result of the procedure, should be immediately available. If a serious reaction should occur, immediately discontinue administration and institute appropriate treatment. Since severe delayed reactions have been known to occur, emergency facilities and competent personnel should be available for at least 30 to 60 minutes after administration.
The reported incidences of adverse reactions to contrast media are twice as high in patients with a history of allergy than in the general population. Patients with a history of previous reactions to a contrast medium or iodine are three times more susceptible than other patients. Most adverse reactions to intravascularly injected contrast agents appear within one to 30 minutes after the start of injection, but delayed reactions may occur.
Before a contrast medium is injected, the patient should be questioned for a history of bronchial asthma or allergy.
Although a history of allergy may imply a greater than usual risk, it does not arbitrarily contraindicate the use of the medium. Premedication with corticosteroids to avoid or minimize possible allergic reactions may be considered.
The possibility of an idiosyncratic reaction in patients who have previously received a contrast medium without ill effect should always be considered. A positive history of bronchial asthma or allergy, a family history of allergy, or a previous reaction of hypersensitivity to another contrast agent warrant special attention. Such a history, by suggesting proneness to reactions, may be more accurate than pre-testing in predicting the potential for reaction, although not necessarily the severity or type of reaction in the individual case. A positive history of this type does not arbitrarily contraindicate the use of contrast agent, when a diagnostic procedure is thought essential, but calls for caution.
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 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 dose. Severe reactions and fatalities have occurred with the full dose after a non-reactive test dose, and with or without a history of allergy.
Prophylactic therapy with corticosteroids should be considered for patients who present with a strong allergic history, a previous reaction to a contrast medium, or a positive pre-test (since in these patients the incidence of reaction is two to three times that of the general population). Adequate doses of corticosteroids should be started early enough prior to contrast medium injection to be effective and should continue through the time of injection and for 24 hours after injection. Corticosteroids should not be mixed in the same syringe with the contrast medium because of chemical incompatibility.
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. Administration of Optiray should be postponed in patients with hepatic or biliary disorders who have recently taken a cholecystographic agent. An interval of at least 48 hours should be allowed between examinations, especially in patients with reduced renal reserve. Especially 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 patients with diabetic nephropathy and in susceptible non-diabetic patients (often elderly with pre-existing renal disease) following administration of iodinated contrast agents. Careful consideration of the potential risks should be given before performing radiographic procedures with Optiray (ioversol) in these patients.
INTRAVASCULAR: Diagnostic procedures which involve the use of iodinated intravascular contrast agents should be carried out under the direction of a physician skilled and experienced in the particular procedure to be performed.
Reports of thyroid storm occurring following intravascular use of iodinated radiopaque agents in patients with hyperthyroidism or with an autonomously functioning thyroid nodule, suggest that this additional risk be carefully evaluated in such patients before use of Optiray.
Special precaution is advised in patients with increased intra-cranial pressure, cerebral thrombosis or embolism, primary or metastatic cerebral lesions, subarachnoid hemorrhage, arterial spasm, transient ischemic attacks, and in any condition when the blood-brain barrier is breached or the transit time of the contrast agent material through the cerebral vasculature is prolonged, since clinical deterioration, convulsions, and serious temporary or permanent neurological complications (including stroke, aphasia, cortical blindness, etc.) may occur following intravenous or intra-arterial injection of relatively large doses of contrast media. Such patients, and patients in clinically unstable or critical condition should undergo examinations with intravascular contrast media only if in the opinion of the physician the expected benefits outweigh the potential risks, and the dose should be kept to the absolute minimum.
When considering the use of high doses of contrast media, caution should be exercised in patients with congestive heart failure because of the transitory increase in circulatory osmotic load, and such patients should be kept under surveillance for several hours in order to detect delayed hemodynamic disturbances.
There have been reports in the literature indicating that patients on adrenergic beta-blockers may be more prone to severe adverse reactions to contrast media. At the same time, treatment of allergic-anaphylactoid reactions in these patients is more difficult. Adrenaline should be administered with caution since it may not exert its usual effects. On the one hand larger doses of adrenaline may be needed to overcome the bronchospasm, while on the other, these doses can be associated with excessive alpha adrenergic stimulation with consequent hypertension, reflex bradycardia and heart-block and possible potentiation of bronchospasm. Alternatives to the use of large doses of adrenaline include vigorous supportive care such as fluids and the use of beta agonists including parenteral salbutamol or isoproterenol to overcome bronchospasm and norepinephrine to overcome hypotension.
In angiographic procedures, the presence of a vigorous pulsatile flow should be established before using a catheter or pressure injection technique. A small "pilot" dose of about 1-2 mL should be administered to locate the exact site of needle or catheter tip to help prevent injection of the main dose into a branch of the aorta or intramurally. Great care should be taken to avoid the entry of a large concentrated bolus into an aortic branch.
Mesenteric necrosis, acute pancreatitis, renal shutdown, serious neurologic complications including spinal cord damage and hemiplegia or quadriplegia have been reported following inadvertent injection of a large part of the aortic dose of contrast media into an aortic branch or arterial trunks providing spinal or cerebral artery branches.
Pulsation must be present in the artery to be injected. Extreme caution is advised in considering peripheral angiography in patients suspected of having thromboangiitis obliterans (Buerger's disease) since any procedure (even insertion of needle or catheter) may induce a severe arterial or venous spasm. Caution is also advisable in patients with severe ischemia associated with ascending infection. Special care is required in patients with suspected thrombosis, ischemic disease, local infection or a significantly obstructed vascular system. Occasional serious neurologic complications, including paraplegia, have been reported in patients with aorta-iliac or femoral artery bed obstruction, abdominal compression, hypotension, hypertension and following injection of vasopressors.
When large individual doses are administered an appropriate time interval should be permitted to elapse between injections to allow for subsidence of hemodynamic disturbances. Angiography should be avoided whenever possible in patients with homocystinuria because of the risk of inducing thrombosis and embolism. Following catheter procedures, gentle pressure hemostasis is advised followed by immobilization of the limb for several hours to prevent hemorrhage from the site of arterial puncture.
Intravenous Contrast Enhancement in Computed Tomography: Following injection of relatively large doses of contrast media used in the procedure, transient or permanent neurological changes have been reported.
Use in Pregnancy: No teratogenic effects attributable to Optiray (ioversol) have been observed to date in studies performed in animals. There are no studies on the use of Optiray in pregnant women. Many injectable contrast media cross the placental barrier in humans and appear to enter fetal tissue passively. Optiray probably crosses the placental barrier in humans by simple diffusion to reach fetal tissue. Optiray should be used during pregnancy only if the benefit to the mother clearly outweighs the risk to the fetus. It should be borne in mind that X-ray procedures involve a certain risk related to exposure of the fetus.
Use in Lactation: Because contrast media are secreted in human milk, if the administration of Optiray is considered to be essential, breast feeding should be discontinued for at least 48 hours following the procedure.
Use in Children: Some pediatric patients have a higher risk of adverse reactions to contrast media. Such patients may include those with sensitivity to allergens, including other drugs, those with asthma, congestive heart failure, a serum creatinine > 1.5 mg/dL, or ages under 12 months.
Use in the Elderly: The tolerance of elderly patients to drugs in general is diminished. These patients may have reduced renal reserve, impaired general health and may be taking medication (e.g. adrenergic B-blockers) which make them more susceptible to the potentially harmful effects of procedures involving the use of contrast media. The need for and the expected benefits of the procedure have to be carefully evaluated and dosage should be very conservative.