INTERACTIONS
7.1 Drug-Drug Interactions Metformin In patients with renal impairment, metformin can cause lactic acidosis. Iodinated contrast agents appear to increase the risk of metformin-induced lactic acidosis, possibly as a result of worsening renal function. Stop metformin at the time of, or prior to, iopamidol injection administration in patients with an eGFR between 30 and 60 mL/min/1.73 m 2 ; in patients with a history of hepatic impairment, alcoholism, or heart failure; or in patients who will be administered intra-arterial iodinated contrast agents. Re-evaluate eGFR 48 hours after the imaging procedure and reinstitute metformin use only after renal function is stable.
Radioactive Iodine
Administration of iopamidol injection may interfere with thyroid uptake of radioactive iodine (I-131 and I-123) and decrease therapeutic and diagnostic efficacy. Avoid thyroid therapy or testing for up to 6 weeks post iopamidol injection
7.2 Drug-Laboratory Test Interactions Protein-Bound Iodine Test Iodinated contrast agents, including iopamidol injection, will temporarily increase protein-bound iodine in blood. Avoid protein-bound iodine test for at least 16 days following administration of iopamidol injection . However, thyroid function tests that do not depend on iodine estimations, e.g., triiodothyronine (T 3 ) resin uptake and total or free thyroxine (T 4 ) assays, are not affected.
CONTRAINDICATIONS Intrathecal administration of corticosteroids with iopamidol is contraindicated. Because of overdosage considerations, immediate repeat myelography in the event of technical failure is contraindicated (see interval recommendation under DOSAGE AND ADMINISTRATION ). Myelography should not be performed in the presence of significant local or systemic infection where bacteremia is likely.
AND PRECAUTIONS Hypersensitivity Reactions: Life-threatening or fatal reactions can occur. Always have emergency resuscitation equipment and trained personnel available. ( 5.2 )
Acute Kidney
Injury: Acute injury including renal failure can occur. Use the lowest dose and maintain adequate hydration to minimize risk. ( 5.3 )
Cardiovascular Adverse
Reactions: Hemodynamic disturbances including shock and cardiac arrest may occur during or after iopamidol injection administration. ( 5.4 )
Thyroid
Dysfunction in Pediatric Patients 0 Years to 3 Years of Age: Individualize thyroid function monitoring based on risk factors such as prematurity. ( 5.8 )
5.1 Risks Associated with Intrathecal Administration Intrathecal administration, even if inadvertent, can cause death, convulsions, cerebral hemorrhage, coma, paralysis, arachnoiditis, acute renal failure, cardiac arrest, seizures, rhabdomyolysis, hyperthermia, and brain edema. Iopamidol injection is for intra-arterial or intravenous use only and must not be administered intrathecally <span class="opacity-50 text-xs">[see Dosage and Administration ( 2.1 )]</span>.
5.2 Hypersensitivity Reactions Iopamidol injection can cause life-threatening or fatal hypersensitivity reactions including anaphylaxis. Manifestations include respiratory arrest, laryngospasm, bronchospasm, angioedema, and shock <span class="opacity-50 text-xs">[see Adverse Reactions ( 6.2 )]</span> . Most severe reactions develop shortly after the start of injection (e.g., within 1 to 3 minutes), but delayed reactions can also occur. There is increased risk of hypersensitivity reactions in patients with a history of previous reactions to contrast agents, and allergic disorders (i.e., bronchial asthma, allergic rhinitis, and food allergies) or other hypersensitivities. Premedication with antihistamines or corticosteroids to avoid or minimize possible allergic reactions does not prevent serious life-threatening reactions but may reduce both their incidence and severity. Obtain a history of allergy, hypersensitivity, or hypersensitivity reactions to iodinated contrast agents and always have emergency resuscitation equipment and trained personnel available prior to iopamidol injection administration. Monitor all patients for hypersensitivity reactions.
5.3 Acute Kidney Injury Acute kidney injury, including renal failure, may occur after iopamidol injection administration. Risk factors include: pre-existing renal insufficiency, dehydration, diabetes mellitus, congestive heart failure, advanced vascular disease, elderly age, concomitant use of nephrotoxic or diuretic medications, multiple myeloma or other paraproteinemias, and repetitive or large doses of iopamidol injection. Use the lowest necessary dose of iopamidol injection in patients with renal impairment. Adequately hydrate patients prior to and following iopamidol injection administration. Do not use laxatives, diuretics, or preparatory dehydration prior to iopamidol injection administration.
5.4 Cardiovascular Adverse Reactions Iopamidol injection increases the circulatory osmotic load and may induce acute or delayed hemodynamic disturbances in patients with congestive heart failure, severely impaired renal function, combined renal and hepatic disease, and combined renal and cardiac disease, particularly when repetitive or large doses are administered. Fatal cardiovascular reactions have occurred mostly within 10 minutes of iopamidol injection; the main feature was cardiac arrest with cardiovascular disease as the main underlying factor. Hypotensive collapse and shock have occurred. Cardiac decompensation, serious arrhythmias, and myocardial ischemia or infarction can occur during coronary arteriography and ventriculography. The administration of iopamidol injection may cause pulmonary edema in patients with heart failure. Based upon published reports, deaths associated with the administration of iodinated contrast agents range from 6.6 per 1 million (0.00066 percent) to 1 in 10,000 patients (0.01 percent). Use the lowest necessary dose of iopamidol injection in patients with congestive heart failure and always have emergency resuscitation equipment and trained personnel available. Monitor all patients for severe cardiovascular reactions.
5.5 Thromboembolic Events Serious, in some cases fatal, thromboembolic events, including myocardial infarction and stroke, can occur during angiographic procedures. During these procedures, increased thrombosis and activation of the complement system occurs. Risk factors for developing thromboembolic events include: length of procedure, catheter and syringe material, underlying disease state, and concomitant medications. To minimize thromboembolic events, use meticulous angiographic techniques and minimize the length of the procedure. Avoid blood remaining in contact with syringes containing iodinated contrast agents, which increases risk of clotting. Avoid angiocardiography in patients with homocystinuria because of the risk of inducing thrombosis and embolism.
5.6 Extravasation and Injection Site Reactions Extravasation can occur with iopamidol injection administration, particularly in patients with severe arterial or venous disease. Inflammation, blistering, skin necrosis, and compartment syndrome have been reported following extravasation. In addition, injection site reactions such as pain and swelling at the injection site can also occur <span class="opacity-50 text-xs">[see Adverse Reactions ( 6.2 )]</span> . Ensure intravascular placement of catheters prior to injection. Monitor patients for extravasation and advise patients to seek medical care for progression of symptoms.
5.7 Thyroid Storm in Patients with Hyperthyroidism Thyroid storm has occurred after the intravascular use of iodinated agents in patients with hyperthyroidism or with an autonomously functioning thyroid nodule. Evaluate the risk in such patients before use of iopamidol injection
5.8 Thyroid Dysfunction in Pediatric Patients 0 Years 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 agents in pediatric patients 0 years 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 iodinated contrast agent exposure. Pediatric patients with congenital cardiac conditions may be at 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 iodinated contrast agents, individualize thyroid function monitoring based on underlying risk factors, especially in term and preterm neonates.
5.9 Hypertensive Crisis in Patients with Pheochromocytoma Hypertensive crisis in patients with pheochromocytoma has occurred with iodinated contrast agents. Closely monitor patients when administering iopamidol injection if pheochromocytoma or catecholamine-secreting paragangliomas are suspected. Inject the minimum amount of iopamidol injection necessary and have measures for treatment of hypertensive crisis readily available.
5.10 Sickle Cell Crisis in Patients with Sickle Cell Disease Iodinated contrast agents can promote sickling in individuals who are homozygous for sickle cell disease. Hydrate patients prior to and following iopamidol injection administration and use only if the necessary imaging information cannot be obtained with alternative imaging modalities.
5.11 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 a contrast agent; prophylactic medications may not prevent or mitigate severe cutaneous adverse reactions. Avoid administering iopamidol injection to patients with a history of a severe cutaneous adverse reaction to iopamidol injection.
5.12 Interference with Laboratory Tests Iopamidol injection can interfere with protein-bound iodine test <span class="opacity-50 text-xs">[see Drug Interactions ( 7.2 )]</span> .