Adverse Reactions to Contrast Agents: Dispelling the Myths

IV iodinated contrasts are primarily used for CT scans and are the most popular of all contrast agents (Rogers & Tadi, 2023). Usually, water-soluble contrast agents are used IV in CT imaging for better visualization of vascular structures and hypervascular tissues.

IV contrasts were once used routinely for X-rays. This is no longer in practice. While iodine is a natural element found in humans, it can be toxic in contrast if not changed to a larger molecular structure by a binding agent. In the past, binding agents had very high osmolality (five to eight times that of blood) (Rogers & Tadi, 2023). Over time, due to adverse reactions such as severe pain, lower osmolality binding agents began to be favored (only three times the osmolality of blood). Lowering the osmolality, ion levels, and viscosity of IV contrast agents makes them less likely to cause complications (ACR, 2025; Rogers & Tadi, 2023). Iodinated IV contrast has a plasma half-life of two hours. After 24 hours, the contrast should have cleared from the bloodstream in patients without renal impairment, as the contrast is excreted primarily through the kidneys (Rogers & Tadi, 2023).

The risk of adverse reactions from iodinated contrast agents used in imaging is well-established (ACR, 2025). However, the exact etiology of contrast reactions after intravascular iodinated contrast agents is not well known (ACR, 2025). The average incidence of allergic reactions for nonionic formulations is approximately 3% or less. The assumption is that the incidence of ionic contrast agents is higher than that of nonionic contrast agents. Low-osmolality nonionic compounds are associated with fewer adverse reactions when administered via IV. Nonionic iso-osmolar agents are hydrophilic. These hydrophilic agents are better for use in patients at increased risk for contrast-induced acute kidney injury (CI-AKI) (will be discussed later).

Gastrointestinal contrast agents primarily include oral iodine-based agents and oral bariums (Patel et al., 2024). Rectal agents are an option as well. Unlike iodine-based agents, which are absorbed systemically, bariums are less likely to be absorbed in the bloodstream, making them ideal for preventing iodine-related adverse reactions (Patel et al., 2024). However, iodine-based agents are less favored due to taste and expense. This course will focus on bariums.

Barium sulfate mixtures are used to opacify the bowel during fluoroscopies, CT, and MRIs of the gastrointestinal system (ACR, 2025). Barium sulfate comes in a powder form and may need to be reconstituted with water. Administration volume may vary depending on the study performed and the patient's anatomy. The contrast agent is administered orally about 1.5-2 hours prior to imaging to allow for appropriate transit within the bowel. High-osmolality iodinated contrast agents should be avoided in patients who are at risk for aspiration (ACR, 2025; U.S. Food and Drug Administration [FDA], 2020). Aspirated high-osmolality contrast agents can cause chemical pneumonitis with associated pulmonary edema. Aspiration of large volumes of both barium-based and iodinated oral contrast agents has rarely been reported as fatal.

A main complication of oral contrast is leakage into the mediastinum or peritoneal cavity, which can lead to mediastinitis and peritonitis (ACR, 2025). Leakage can occur in conditions including gastrointestinal fistulas, ulcers, lesions, inflammatory bowel disease, diverticulitis, or appendicitis (FDA, 2020). Contraindications to barium contrast include allergy, known bowel obstruction, and known or suspected bowel perforation. Clinicians should encourage increased fluid intake after barium administration as this type of contrast is not water-soluble and can cause constipation, obstruction, or impaction (ACR, 2025;FDA, 2020).

Gadolinium-based contrast agents (GBCAs) are used for MRIs and magnetic resonance angiography (MRAs). GBCAs are composed of gadolinium, a rare earth heavy metal toxic to humans in its raw form (Choi & Moon, 2019). For this reason, all gadolinium-based contrast agents are chelated (bonding of ions) to make them less toxic or non-toxic while also allowing for renal excretion. While GBCAs are deemed generally safe when administered in recommended doses, they do carry risks (Choi & Moon, 2019). Mild reactions from the composition of gadolinium-based agents typically occur in about 1% of all patients (ACR, 2025). The most common are headache, nausea, vomiting, itching, rash, distorted taste, and cold sensation at the injection site (Ibrahim et al., 2023; Mafraji, 2025a). Severe and anaphylactic reactions are extremely rare.

In 2018, the FDA reported that gadolinium can remain in patients' bodies, including the brain, for months and even years after receiving the agent (FDA, 2018). Patients at risk for GBCA retention include those who require multiple lifetime doses, pregnant people, children, and patients with inflammatory conditions. While GBCA retention is not necessarily problematic in patients with normal kidney function, gadolinium is excreted in the kidneys, and patients with kidney failure are at an increased risk for developing nephrogenic systemic fibrosis (will be discussed later) (FDA, 2018).

Despite these risks, clinicians are discouraged from avoiding diagnostic tests requiring contrast agents for patients who need them. Rather, they should minimize repeated studies if possible and ensure patients are aware of all risks.

Unlike CT and MRI contrasts, ultrasound IV contrast consists of injected microbubbles within solutions/fats/crystals (Frinking et al., 2020). The use of ultrasound contrast agents in the U.S. is not yet ubiquitous but continues to gain considerable ground for certain applications, particularly cardiac imaging. Microbubble compounds contrast ultrasound imaging by altering the acoustic impedance between the blood and the injected gas/air. For example, when evaluating for cardiac shunts (blood flow deviations within the heart due to holes in the chamber walls), a patient may undergo an echocardiogram with "agitated saline." This exam is performed by an ultrasound technician and a nurse. The tech takes images of the heart while the nurse agitates a saline flush syringe and injects the tiny air bubbles within the saline into the patient's bloodstream through an IV. As the saline quickly flows through the vascular system, the tech observes for movement of the bubbles from one chamber to another through the heart wall, indicating that a tiny hole exists in the wall.

Other off-label uses of ultrasound agents in practice (or under investigation) include (ACR, 2025):

• Assessment of blood flow dynamics in tumors.
• Differentiation of benign kidney cysts from solid kidney masses.
• Detection of solid organ injury (in trauma cases).
• Detection of bowel wall inflammation in Crohn's disease.
• Detection of endoleaks after abdominal aortic aneurysm repair.

Although ultrasound contrast bubbles are very small, they are too large to move through the extracellular space like CT and MRI contrast. Instead, the bubbles stay in the vascular system for about ten minutes before they rupture and dissolve on their own (the gas is eliminated through the lungs) (ACR, 2025). Ultrasound contrasts are generally safe and do not carry the risk of nephrotoxicity when administered in approved doses.

The first ultrasound agent was introduced in the late 1960s, and more solutions and encapsulations were used over time, including lipids and human albumin (Frinking et al., 2020). Although ultrasound contrast agents are a progressive development, one challenge is bubble size as some are not the appropriate size for optimal imaging of certain body regions. Broad clinical acceptance of ultrasound contrasts beyond cardiology requires further research and development.

It is common knowledge that any history of allergic reactions predisposes individuals to future allergic reactions to other substances. A history of allergic reactions is sometimes challenging to evaluate in clinical practice because the definition of allergic reactions is not as clear to a patient reporting them as it is to providers, nurses, and other healthcare team members. For example, seasonal rhinitis is a very common allergy, but this would not be a symptom that would be documented as an allergic reaction.

A prior allergy-like reaction to contrast media increases the risk of a subsequent reaction by up to five-fold (the risk is two- to three-fold for those without prior allergic reactions) (ACR, 2025). If the patient reports a history of allergies, the providers and other clinical staff should focus specifically on the type of reaction, the specific contrast agent involved in the reaction (not just the agent class), the type of symptoms experienced, and the duration of the symptoms. The goal here is to establish the severity of the "allergy reaction" in order to clearly identify patients who may be atopic.

Past Medical History

A history of asthma may confer an increased risk of developing an allergic reaction to contrast agents (particularly bronchospasm). Because the risk is so low, clinicians are advised against withholding contrast (or pre-medicating) for patients with asthma.

Patients with cardiovascular disease issues such as angina, congestive heart failure, severe aortic stenosis, primary pulmonary hypertension, or cardiomyopathy are at risk for adverse reactions to contrast agents, particularly cardiac-related reactions. In this group of patients, the volume of contrast and the osmolality of the contrast agents administered are critical because these two factors affect the cardiovascular status significantly. As with asthma, clinicians are advised against withholding contrast due to the low risk.

There are a few studies that have shown that the patient's emotional state can affect the occurrence of adverse effects to contrast agents. In a patient with a known history of anxiety, pre-medication with anti-anxiety medications or reassurance prior to the test can be helpful.

Infants and neonates are at increased risk for adverse effects of contrast agents. Contrast volume is an important consideration because of the low blood volume of patients in this age group. Low blood volume makes them at increased risk for hyperosmolality with its associated cardiotoxic effects.

Renal insufficiency prior to the administration of iodinated contrast increases the risk of CI-AKI and nephrogenic systemic fibrosis, which will be discussed later in this course. Patients with acute renal failure, as well as those with end-stage renal disease (ESRD), are at increased risk.

Some reports have suggested that the use of beta-blockers lowers the systemic threshold for contrast reactions and could potentially limit the effectiveness of epinephrine administered if a reaction occurs. However, the evidence for this is not significant enough to warrant pre-medication based solely on the use of beta-blockers. In fact, patients on beta-blockers do not need to discontinue their medications prior to the administration of contrast agents (ACR, 2025).

Patients with thyroid disease are at risk for adverse thyroid hormone-related reactions to contrast agents. For example, iodinated contrast is not recommended in patients with hyperthyroidism, particularly those in acute thyroid storm, as it can lead to thyrotoxicosis, although rare. For patients without thyroid disease, iodinated contrast does not affect thyroid function. Another example is bariums: certain bariums, such as iodinated water-soluble biliary agents, can alter thyroid function tests in patients with thyroid disease (FDA, 2020).

Patients with certain food intolerances may experience adverse reactions from contrast agents that contain certain food elements/nutrients. For example, although rare, patients with fructose intolerance may experience complications with bariums that contain sorbitol, including vomiting, hypoglycemia, jaundice, liver enlargement, and kidney failure (FDA, 2020).

These reactions can either occur acutely or can be delayed for up to one week after the administration of contrast agents. Allergic-type reactions have an unclear etiology and occur above an unknown threshold. They are not dose- nor concentration-related. Allergic-type contrast reactions are likely independent of dose and concentration above a certain unknown threshold. For example, allergic reactions to barium sulfate are rare and most likely associated with additives within the preparation rather than the contrast itself (ACR, 2025;FDA, 2020).

These are typically related to chemical attributes related to the specific molecules within contrast agents, such as hyperosmolality or chemotoxicity. Physiological reactions tend to be dose- and concentration-dependent. Examples related to bariums include nausea, vomiting, abdominal cramping, diarrhea, electrolyte imbalances (hypokalemia), and vasovagal reactions related to bowel distention (ACR, 2025; FDA, 2020). Examples related to IV contrasts include cardiac arrhythmias and seizures.

In general, acute adverse reactions can be considered either allergic or physiological, which can then be graded as mild, moderate, or severe. Note that this classification is used for both reactions to iodinated contrast media as well as gadolinium-based contrast agents.

Mild symptoms tend to be self-limited and require no further treatment. They tend to resolve without progressing to a more severe reaction. Mild reactions can further be characterized as allergic-type or physiological.

These reactions typically require medical treatment and can become severe if not well-treated. As such, clinical team members must remain vigilant when these reactions occur. Like mild reactions, moderate reactions can be characterized as allergic-type or physiological.

Symptoms associated with severe reactions can be life-threatening and carry a significant risk for morbidity or death if they are not addressed promptly and appropriately. Unfortunately, both allergic-like and physiological reactions can result in cardiopulmonary arrest. GBCAs, for example, can cause severe reactions (although rare), including anaphylactic shock, respiratory distress, laryngeal edema, cardiac/respiratory arrest, shock, and nephrogenic systemic fibrosis (Ibrahim et al., 2023). Sometimes it is unclear what type of reaction caused the cardiopulmonary arrest.

Pulmonary edema is a rare, severe reaction that can occur regardless of cardiac reserves. Patients with low cardiac reserves get cardiogenic pulmonary edema, while patients with normal cardiac reserves get noncardiogenic pulmonary edema. Pulmonary embolisms, coagulation problems, and blood infections can occur with certain contrasts, such as barium when entering the vascular system (FDA, 2020).

Severe Reaction

Delayed adverse reactions typically occur 30 minutes to one week or more after the administration of the contrast agent, most commonly between three hours and two days. Delayed reactions are more likely following the administration of an ionic contrast agent than a nonionic contrast agent. The typical symptoms of delayed reactions involve itching and hives, and they are treated with antihistamines or topical steroids. Other reactions may include nausea, vomiting, fever, drowsiness, headache, and hypotension, and may be treated with antipyretics, antiemetics, and fluid resuscitation.

Think about the last time you encountered an IV infiltration. Depending on the solution that was injected or infused at the time, the patient likely had an array of symptoms, most notably pain. Now imagine the difference between IV infiltration after infusion of normal saline versus a chemical agent like contrast. You can only imagine the potential complications that may ensue. Contrast media extravasation (CMEX) occurs when IV contrast leaks into the tissues after administration. This can happen if the extremity of the IV is ill-positioned during infusion, a distal IV site is accessed, or small-gauge needles are used (Rogers & Tadi, 2023). CMEX is characterized by progressive pain, sensation loss, and mobility impairment of the affected extremity.

Power injectors are often used to infuse IV contrast at a particular rate, time, and volume specific to the patient, indication, and type of equipment (Rogers & Tadi, 2023). Power injectors warrant the insertion of at least a 20-gauge IV, preferably in the antecubital area (ACR, 2025; Roditi et al., 2022). Additionally, the patient's arm should be positioned properly to avoid impedance of blood flow through the IV. CMEX usually goes away on its own with supportive care and monitoring, but if a larger volume of contrast is used, the patient may be at risk for compartment syndrome, vascular compromise, and skin ulcerations (Roditi et al., 2022; Rogers & Tadi, 2023). Treatment for CMEX includes raising the limb and applying cold compresses. Severe cases may require surgical intervention. Power injector use also increases the risk of air embolism, characterized by shortness of breath, chest pain, hypotension, tachycardia, and wheezing (ACR, 2025). Air embolisms are treated with 100% oxygen and assisting the patient to a left side-lying position.

Note: Careful consideration must be taken with children who receive IV contrasts, as any discomfort at the IV site can cause the child to move, complicating the exam or necessitating the need for repeated exams (ACR, 2025).

CI-AKI – previously termed contrast-induced nephropathy – is a type of renal failure that occurs within 24-48 hours after the administration of contrast agents. While the pathophysiology is not entirely understood, evidence suggests contrast agents may affect renal vasoconstriction or have a direct toxic effect on the renal tubules (ACR, 2025). It is important to note that other causes of acute kidney injury must be excluded prior to diagnosing CI-AKI. Acute kidney injury is characterized by at least one of the following within 48 hours after contrast administration (ACR, 2025; Gameiro et al., 2020):

• Absolute increase in the serum creatinine of 0.3 milligrams per deciliter (mg/dl)
• Increase in creatinine of more than 1.5 times the patient's baseline
• Reduction in urine output of less than 0.6 milliliters per kilogram per hour (mL/kg/hr) for at least six hours

The risk of CI-AKI is very low in patients with normal renal function – that is, a glomerular filtration rate (GFR) greater than 60 ml/minute. In general, CI-AKI is self-limiting, and the renal function should return to baseline within seven to ten days, peaking by day four, without progressing to chronic renal failure. On the other hand, if a patient has an abnormal renal function at baseline – that is, a GFR less than 60 ml/minute – then the risk of CI-AKI is much higher. This is especially true in older adults with diabetes. Other risk factors for CI-AKI include hypertension, hemodynamic instability, dehydration, congestive heart failure, and receiving multiple doses of contrast within a 24-hour period (ACR, 2025).

It is also important to note that patients who take metformin are at risk for lactic acidosis if they develop CI-AKI from iodinated contrast (ACR, 2025; Mafraji, 2025b). Metformin is not only 90% excreted by the kidneys, but it also can cause increased lactic acid production; so, if the kidneys are damaged, the patient may develop lactic acidosis, which can be fatal (ACR, 2025). For this reason, metformin should be stopped at the time an iodinated contrast agent is administered and held for at least 48 hours until satisfactory renal function is ensured.

Interventions to prevent CI-AKI include pre- and post-hydration. Before the exam, IV fluids are administered starting one hour before and up to three to 12 hours after. Increased oral fluid intake has not been sufficiently studied in patients with underlying renal impairment. Prevention is key and involves performing patient-specific risk-benefit assessments, using a low osmolality contrast in patients with underlying renal disease, and administering contrasts at safe, recommended doses (ACR, 2025).

Nephrogenic systemic fibrosis is associated with GBCA use in MRIs; it is a fibrotic disease of the body, mostly involving the skin and tissues, that begins with skin thickening and itching and can progress rapidly to contractures and joint immobility (ACR, 2025). In some cases, the disease is fatal. Most patients who develop nephrogenic systemic fibrosis have underlying kidney disease (ESRD, AKI, or receiving dialysis) and have received large doses of GBCAs or multiple doses within a short period of time.

The pathophysiology of nephrogenic systemic fibrosis is not entirely understood, but a theory exists. As mentioned earlier, gadolinium is a naturally occurring heavy metal that is toxic to humans in its raw form and requires chelation (bonding of ions) to become safe for use. In patients with renal disease, it is hypothesized that gadolinium ions dissociate from the chelates within the GBCAs due to prolonged renal clearance times and other metabolic factors. The free gadolinium binds to anions in the body (like phosphate), creating a substance that stays in the tissues, resulting in tissue fibrosis over time (ACR, 2025).

There are very limited treatment options for nephrogenic systemic fibrosis. Therefore, prevention is key. Dose adjustments, avoidance of certain high-risk GBCAs, and/or an alternative diagnostic test should be considered.

Think about a patient who will receive a blood transfusion under your care. If the patient reported they had a mild to moderate reaction to blood transfusions in the past, the provider may order an antihistamine to be administered prior to beginning the transfusions. Why? Because the patient may have a higher likelihood of having another transfusion reaction compared to a patient who has never had a reaction. While this case applies to patients who have had prior reactions, some clinicians may prefer to carry out these same actions in patients at risk for an allergic-like contrast reaction, even if the patient has not had a contract reaction in the past. This practice, however, is not always recommended and has its risks. Patients at risk for severe allergic contrast reactions include those with asthma, allergies/atopy, or a history of prior allergic-like reactions to contrast agents (Mafraji, 2025b; European Society of Urogenital Radiology [ESUR], 2022).

Antihistamines and corticosteroids are often the medications of choice for medicating before and after an allergic reaction. However, studies show pre-medication is not always effective in preventing reactions in those at risk and can cause problems such as corticosteroid-induced hyperglycemia (up to 80 to 150 mg/dL over baseline) and longer lengths of stay (ACR, 2025; Umakoshi et al., 2020). Other problems include infection risk, transient leukocytosis after 24 to 48 hours of corticosteroid administration, and drowsiness after diphenhydramine (ACR, 2025).

While many providers believe pre-medication to be beneficial, there is little evidence on the effectiveness of this practice. The ACR recommends against routine pre-medication but suggests this practice on a case-by-case basis. However, some experts (such as the ESUR) recommend against pre-medication due to its ineffectiveness, instead opting for an alternative test (ESUR, 2022; Umakoshi et al., 2020).

Clinicians should follow their facility's protocols surrounding pre-medication and be aware that breakthrough reactions can occur despite pre-medication. It is also important to note that pre-medication with antihistamines and corticosteroids does not prevent physiological reactions, such as hypertension, arrhythmias, nausea, or headache (ACR, 2025).

Clinical providers, including some radiologists have commonly believed that there is a link between an allergic reaction to shellfish and an increased risk of allergic reaction to iodinated contrast agents (ACR, 2025). This connection between an allergy to shellfish and iodinated contrast agents was first reported in the 1970s. The assumption is based on the fact that both shellfish and iodinated contrast contain significant amounts of iodine. This idea has led some providers to encourage pre-medication in patients who self-report a shellfish allergy. Providers have even gone as far as recommending against iodinated contrast media in patients with shellfish allergies.

Shellfish allergy remains one of the most common food allergies among adults and also remains a common cause of anaphylactic reactions related to food consumption. Shellfish are separated into two groups.

Allergic Reaction

Reactions to iodine contrast are not true allergic reactions in that IgE does not mediate them, but rather they occur by direct stimulation of mast cells and basophils. The stimulation of these cell types yields a pseudo-allergy-like reaction, also known as an anaphylactoid reaction, whereas a true allergic reaction would produce allergy-specific IgE following exposure, making the patient sensitized to the allergen. Finally, the anaphylactoid reaction that occurs with iodinated contrast media does not occur due to iodine but rather occurs due to the hyperosmolality of the contrast media compared to blood (ACR, 2025; Stewart, 2022).

Even though a large number of providers continue to specifically inquire about shellfish allergy as a way to screen for allergies to iodinated contrast, there is no evidence to support the practice, and it is recommended that the practice be discontinued (ACR, 2025). Like most other allergic reactions, the treatment for shellfish allergies is antihistamines, corticosteroids, and epinephrine, if needed (ACR, 2025).

As with any medication or treatment, clinicians should consider the effect that contract agents have on fetal health. Some agents are not absorbed systemically (like oral barium contrasts) and therefore do not impact fetal health in pregnant patients or those who breastfeed (FDA, 2020). However, for other contrast agents like those in IV form, there may a slight risk involved, especially for patients with preexisting medical conditions.

The half-life of IV-administered iodinated contrast agents is around two hours, by which time almost 100% of the agent is cleared from the bloodstream in patients with normal baseline renal function (provided it was last measured in the previous 24-hour period) (ACR, 2025).

Given that iodinated contrast agents have low lipid solubility, less than 1% of the agents administered are excreted into breast milk. Of the amount of contrast agents ingested by breastfeeding babies, less than 1% is absorbed from the infant's gastrointestinal tract. In effect, the dose presumably absorbed by a breastfeeding infant via the patient's milk is less than 0.01% of the dose administered by IV to the mother.

In comparison, this dose is less than 1% of the standard dose, which would be prescribed to a similar infant for the performance of an iodinated contrast-enhanced imaging study. The standard dose is usually 1.5 to 2 mL/kg for infants (ACR, 2025).

The risks to the infant are direct toxicity and allergic sensitization, or potentially an allergic reaction. It is important to note that these risks remain theoretical and have not been reported in the literature. There is also a risk that if the contrast agent is secreted in the breastfeeding patient's milk, it may alter the taste of the milk.

The ACR recognizes that an informed decision to stop breastfeeding temporarily is one that is made by the patient who is breastfeeding (ACR, 2025). However, they recommend that it is safe for the patient and the infant to continue breastfeeding during the administration of iodinated contrast agents, given that the available data support this position. If the patient still has concerns after reviewing the available data, they could defer breastfeeding for 24 to 48 hours after the administration of the iodinated contrast agent (ACR, 2025; Rogers & Tadi, 2023).

If a patient presents with mild hives (scattered) after administration of a contrast agent, monitoring is typically the only recommendation. Treatment is generally not needed for mild hives unless the patient is symptomatic, which would prompt the need for antihistamines. If hives are moderate, bothersome, widespread, or progressive, vital signs should be monitored, and IV access and patency should be ensured. Depending on the severity level, clinicians might consider diphenhydramine (or fexofenadine, in adults only).

For diffuse erythema, clinicians should monitor vital signs and administer oxygen (six to ten liters is recommended, but clinicians should follow the provider's orders or facility protocol). If a patient is hypotensive, IV fluids (normal saline or lactated Ringer's) should be initiated. If the patient is not responsive to fluid resuscitation, epinephrine may be considered. Clinicians should call an in-house emergency response team (or 911 if in an outpatient setting).

If a patient develops bronchospasms, clinicians should monitor vital signs, administer oxygen, and call for emergency assistance. Depending on the severity of symptoms, clinicians should consider additional therapies. For milder symptoms, beta agonist inhalers are recommended; epinephrine is suggested for moderate symptoms, and both medications are suggested for severe symptoms.

Laryngeal edema, or throat swelling, is a life-threatening emergency that can occur after administration of contrast agents. Should a patient develop this reaction, clinicians should follow their facility's protocol, which may include calling for emergency assistance, administering epinephrine intramuscularly, ensuring IV access/patency, administering oxygen, and monitoring vital signs.

If a patient develops hypotension after contrast administration, fluid resuscitation efforts and postural changes to restore hemodynamic stability should be initiated. As with the reactions above, clinicians should ensure IV access/patency, monitor vital signs, administer oxygen, and call for emergency assistance. Next, the patient's legs should be elevated at least 60 degrees, and IV fluids should be administered (normal saline or lactated Ringer's). If the hypotension is severe and accompanied by bradycardia, atropine may be considered. If the hypotension is severe with tachycardia, clinicians are advised to administer epinephrine. If an adult patient is experiencing a hypertensive crisis (systolic blood pressure > 200 mmHg or diastolic blood pressure > 120 mmHg) after contrast administration, labetalol or a combination of nitroglycerin and furosemide is recommended.

Although rare, pulmonary edema can occur after contrast administration (ACR, 2025). After ensuring optimal IV access, monitoring vital signs, and enlisting emergency assistance, clinicians are advised to raise the head of the bed and administer furosemide (as prescribed) to encourage diuresis and improvement of symptoms.