Radiopaque: Definition, Medical Uses, Interactions, Precautions and Side Effects

When a body offers resistance to being penetrated by X-rays, it appears in the X-rays with white color.

Radiopaque agents are drugs used to diagnose some medical problems. They contain iodine, which absorbs x-rays.

Depending on how they are administered, radiopaque agents accumulate in a particular body area.

The resulting high level of iodine allows X-rays to image the area.

Radiopaque agents are used in the diagnosis of:

• Biliary tract problems : Diatrizoates, Iodipamide, Iohexol, Iodalamate.
• Blood vessel diseases: Diatrizoates, Iohexol, Iopamidol, Iothalamate, Ioversol, Ioxaglate, Metrizamide.
• Diseases of the blood vessels of the brain: Diatrizoates, Iohexol, Iopamidol, Iothalamate, Ioversol, Ioxaglate.
• Diseases of the blood vessels of the heart: Diatrizoates, Iohexol, Iopamidol, Iothalamate, Ioversol, Ioxaglate, Metrizamide.
• Brain diseases and tumors: Diatrizoates, Iohexol, Iopamidol, Iodalamate, Ioversol, Ioxaglate, Metrizamide.
• Breast lesions: Diatrizoates.
• Heart diseases : Diatrizoates, Iohexol, Iopamidol, Iothalamate, Ioversol, Ioxaglate, Metrizamide.
• Altered flow of cerebrospinal fluid in the brain : Iohexol, Iopamidol, Metrizamide.
• Kidney diseases : Diatrizoates, Othalamate, Ioversol, Ioxaglate.
• Joint diseases: Diatrizoates, Iohexol, Iothalamate, Ioxaglate, Metrizamide.
• Liver diseases: Diatrizoates, Iohexol, Iothalamate, Ioversol, Ioxaglate.
• Pancreas disease: Diatrizoates, Iohexol, Iothalamate, Ioversol, Ioxaglate.
• Spinal Disc Diseases: Diatrizoates.
• Spleen diseases: Diatrizoates, Othalamate.
• Stomach and intestinal problems: Diatrizoates, Iohexol.
• Urinary tract problems : Diatrizoates, Iohexol, Iopamidol, Iothalamate, Ioversol, Ioxaglate, Metrizamide.

Radiopaque agents are taken by mouth or given by enema or injection. X-rays are then used to check for any problems with the stomach, intestines, kidneys, or other body parts.

Some radiopaque agents, such as Iohexol, Iopamidol, and Metrizamide, are given by injection into the spinal canal. X-rays diagnose problems or diseases in the head, spinal canal, and nervous system.

The doses of radiopaque agents will be different for different patients and depend on the type of test. The strength of the solution is determined by the amount of iodine it contains.

Different tests will require a different concentration and amount of solution depending on the patient’s age, the contrast needed, and the x-ray equipment used.

After the test, the patient passes most of the solution by urinating (after bladder or ureter studies) or from the vagina (after uterine or fallopian tube studies).

Radiopaque agents should only be used by or under the direct supervision of a physician.

This product is available in the following dosage forms:

• Solution.
• Capsule.

Drug information provided by IBM Micromedex

Before using

When deciding to receive a diagnostic test, the risks of taking the test must be weighed against the benefit it will do. This is a decision that you and your doctor will make.

For these tests, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to medicines in this group or any other medication.

Also, tell your healthcare professional if you have any other allergies, such as food coloring, preservatives, or animals. For nonprescription products, carefully read the label or package ingredients.

Pediatric

Children, especially those with other medical problems, can be susceptible to the effects of radiopaque agents. This can increase the possibility of side effects.

Geriatric

Older people are especially sensitive to the effects of radiopaque agents. This can increase the possibility of side effects.

The pregnancy

Human studies have not been performed with most radiopaque agents. However, Iohexol, Iopamidol, Iothalamate, Ioversol, Ioxaglate, and Metrizamide have not been shown to cause congenital disabilities or other problems in animal studies.

Some radiopaque agents, such as diatrizoates, rarely cause hypothyroidism (underactive thyroid) in the baby when taken late in pregnancy. Also, abdominal X-rays are generally not recommended during pregnancy.

This is to avoid exposing the fetus to radiation. Make sure you have discussed this with your doctor.

Breast-feeding

Although some of these radiopaque agents pass into breast milk, they have not been shown to cause problems in nursing babies.

However, you may need to stop breastfeeding after receiving a radiopaque agent temporarily. Make sure you have discussed this with your doctor.

Drug interactions

Tell your healthcare professional if you take any other prescription or nonprescription (over-the-counter [OTC]) medications.

Other interactions

Using alcohol or tobacco with certain medications can also cause interactions. Talk to your healthcare professional about using your medicine with food, alcohol, or tobacco.

Other medical problems

Be sure to tell your doctor if you have any other medical problems, especially:

• Acute kidney problems due to a severe liver disorder (hepato-renal syndrome [HRS]).
• Critical kidney problems before, during, or after a liver transplant.
• Severe acute or chronic kidney problems: A gadolinium-based contrast agent (GBCA) should be avoided in patients with severe kidney problems.
• The risk of nephrogenic systemic fibrosis (NSF), a severe disease that affects the skin, muscles, and internal organs, may increase.
• Asthma, hay fever, or other allergies (history of): If you account for these conditions, your risk of reacting, such as an allergic reaction to the radiopaque agent, is higher.
• High (severe) blood pressure.
• Pheochromocytoma (PCC): Injection of the radiopaque agent can cause a dangerous increase in blood pressure.
• Liver disease: The radiopaque agent can accumulate in the body and cause side effects.
• Multiple myeloma (bone cancer): Serious kidney problems can develop in patients with this condition.
• Overactive thyroid – A sudden increase in symptoms, such as rapid heartbeat or palpitations, unusual tiredness or weakness, nervousness, excessive sweating, or muscle weakness.
• Sickle cell disease: The radiopaque agent can promote the formation of abnormal blood cells.
• Type 2 diabetes mellitus: There is an increased risk of kidney problems.

Appropriate use

Your doctor may have special instructions for you in preparing for your test. They may prescribe a special diet or a laxative, depending on the type of test.

If you have not received these instructions or do not understand them, check with your doctor in advance.

Your doctor may tell you not to eat for several hours before some tests. This prevents food from returning and entering your lungs during the trial.

You may be allowed to drink small amounts of clear liquids; however, check with your doctor first.

If you are on hemodialysis and are treated with a gadolinium-based contrast agent (GBCA), your doctor may perform hemodialysis immediately after receiving the contrast agent.

Precautions

Make sure your doctor knows if you plan to have a thyroid test shortly. Even after several weeks or months, thyroid test results can be affected by the iodine in this agent.

Seek immediate medical attention if you experience:

• Burning or itching of the skin.
• Red or dark patches.
• Swelling, hardening, and stretching of the skin.
• They raised yellow spots on the whites of the eyes.
• Joint stiffness
• Limited range of motion in the arms and legs.
• Pain that is deep in the hip bone or ribs.
•  Muscular weakness.

These can be symptoms of a severe disease called nephrogenic systemic fibrosis (NSF).

Side effects

Radiopaque agents can cause serious side effects, such as allergic reactions and necessary products. These effects can occur almost immediately or within minutes after the radiopaque agent is administered.

Although these severe side effects appear rarely, your healthcare professional will be prepared to provide immediate medical attention if necessary. If you have any questions about this, ask your doctor.

With oral or rectal use

Less common

• Diarrhea or laxative effect.

With injection into a vein or artery

More common

• Unusual heat and redness of the skin.

Less common

• A cold.
• Dizziness or lightheadedness
• Headache.
• Nausea or vomiting
• Pain or burning at the injection site.
• Perspiration.
• Unusual or metallic taste.
• However unusual.

With injection into the spinal canal

More common

• Back pain.
• Dizziness.
• Headache (mild to moderate).
• Nausea and vomiting (mild to moderate).
• Neck stiffness.
• Less common or rare.
• Difficulty urinating.
• Drowsiness.
• Headache (severe).
• Increased sensitivity of the eyes to light.
• Increased sweating
• Loss of appetite
• Ringing in the ears.
• Unusual tiredness or weakness

Less common

• Hallucinations (hearing or feeling things that are not there).
• Paralysis of one side of the body or the legs and arms.
• For patients receiving gadolinium-based contrast agents (GBCA).
• Unknown incidence.
• Burning or itching of the skin.
• Joint stiffness
• Limited range of motion in the arms, hands, legs, or feet.
• Muscular weakness.
• Deep pain in the hip bone or ribs.
• Red or dark patches on the skin.
• Swelling, hardening, and stretching of the skin.
• Raised yellow spots on the whites of the eyes.

Not all of the side above effects have been reported for each of these agents, but they have been written for at least one.

There are some similarities between these agents, so many of the above side effects can occur with any of them.

Other side effects not mentioned can also occur in some patients. If you notice any other effects, check with your healthcare professional.