Diagnostic radiopaque agents

This information applies to the following medicines:

 * Diatrizoates
 * Iodipamide
 * Iohexol
 * Iopamidol
 * Iothalamate
 * Ioversol
 * Ioxaglate
 * Metrizamide

Category

 * Diagnostic aid, radiopaque, biliary tract disorders: Diatrizoates; Iodipamide; Iohexol; Iothalamate
 * Diagnostic aid, radiopaque, brain disorders: Diatrizoates; Iohexol; Iopamidol; Iothalamate; Ioxaglate; Metrizamide
 * Diagnostic aid, radiopaque, cardiac disease: Diatrizoates; Iohexol; Iopamidol; Iothalamate; Ioversol; Ioxaglate; Metrizamide
 * Diagnostic aid, radiopaque, central nervous system disorders: Iopamidol; Metrizamide
 * Diagnostic aid, radiopaque, cerebrospinal fluid disorders: Iopamidol; Metrizamide
 * Diagnostic aid, radiopaque, contrast enhancer in computed tomography: Diatrizoates; Iohexol; Iopamidol; Iothalamate; Ioversol; Ioxaglate
 * Diagnostic aid, radiopaque, disk disease: Diatrizoates
 * Diagnostic aid, radiopaque, gastrointestinal disorders: Diatrizoates; Iohexol
 * Diagnostic aid, radiopaque, gallbladder disorders: Iodipamide
 * Diagnostic aid, radiopaque, joint disease: Diatrizoates; Iohexol; Iopamidol; Iothalamate; Ioversol; Ioxaglate
 * Diagnostic aid, radiopaque, pancreas disorders: Diatrizoates; Iohexol; Iothalamate
 * Diagnostic aid, radiopaque, peritoneal disorders: Iopamidol; Ioversol
 * Diagnostic aid, radiopaque, splenic and portal vein disorders: Diatrizoates
 * Diagnostic aid, radiopaque, urinary tract disorders: Diatrizoates; Iohexol; Iopamidol; Iothalamate; Ioversol; Ioxaglate; Metrizamide
 * Diagnostic aid, radiopaque, vascular disease: Diatrizoates; Iohexol; Iopamidol; Iothalamate; Ioversol; Ioxaglate; Metrizamide

Description
Radiopaque agents are drugs used to help diagnose certain medical problems. They contain iodine, which absorbs x-rays. Depending on how they are given, radiopaque agents build up in a particular area of the body. The resulting high level of iodine allows the x-rays to make a ``picture'' of the area.

The radiopaque agents are used in the diagnosis of:


 * Biliary tract problems: Diatrizoates, Iodipamide, Iohexol, Iothalamate
 * Blood vessel diseases: Diatrizoates, Iohexol, Iopamidol, Iothalamate, Ioversol, Ioxaglate, Metrizamide
 * Blood vessel diseases of the brain: Diatrizoates, Iohexol, Iopamidol, Iothalamate, Ioversol, Ioxaglate
 * Blood vessel diseases of the heart: Diatrizoates, Iohexol, Iopamidol, Iothalamate, Ioversol, Ioxaglate, Metrizamide]]
 * Brain diseases and tumors: Diatrizoates, Iohexol, Iopamidol, Iothalamate, Ioversol, Ioxaglate, Metrizamide
 * Breast lesions: Diatrizoates
 * Heart disease: Diatrizoates, Iohexol, Iopamidol, Iothalamate, Ioversol, Ioxaglate, Metrizamide
 * Impaired flow of cerebrospinal fluid in brain: Iohexol, Iopamidol, Metrizamide
 * Kidney diseases: Diatrizoates, Iothalamate, Ioversol, Ioxaglate
 * Joint diseases: Diatrizoates, Iohexol, Iothalamate, Ioxaglate, Metrizamide
 * Liver diseases: Diatrizoates, Iohexol, Iothalamate, Ioversol, Ioxaglate
 * Pancreas disease: Diatrizoates, Iohexol, Iothalamate, Ioversol, Ioxaglate
 * Spinal disk diseases: Diatrizoates
 * Spleen diseases: Diatrizoates, Iothalamate
 * 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 if there are any problems with the stomach, intestines, kidneys, or other parts of the body.

Some radiopaque agents, such as iohexol, iopamidol, and metrizamide are given by injection into the spinal canal. X-rays are then used to help 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 how much iodine it contains. Different tests will require a different strength and amount of solution depending on the age of the patient, the contrast needed, and the x-ray equipment used.

Radiopaque agents are to be used only by or under the direct supervision of a doctor.

Before Having This Test
In deciding to use a diagnostic test, any risks of the test must be weighed against the good it will do. This is a decision you and your doctor will make. Also, test results may be affected by other things. For radiopaque agents, the following should be considered:

Allergies
Tell your doctor if you have ever had any unusual or allergic reaction to iodine, to products containing iodine (for example, iodine-containing foods such as seafood, cabbage, kale, rape [turnip-like vegetable], turnips, or iodized salt), or to any radiopaque agent. Also tell your doctor if you are allergic to any other substance, such as sulfites or other preservatives.

Pregnancy
Studies have not been done in humans with most of the radiopaque agents. However, iohexol, iopamidol, iothalamate, ioversol, ioxaglate, and metrizamide have not been shown to cause birth defects or other problems in animal studies.

Some of the radiopaque agents, such as diatrizoates have, on rare occasions, caused hypothyroidism (underactive thyroid) in the baby when they were taken late in the pregnancy. Also, x-rays of the abdomen are usually not recommended during pregnancy. This is to avoid exposing the fetus to radiation. Be sure you have discussed this with your doctor.

Breast feeding
Although some of these radiopaque agents pass into the breast milk, they have not been shown to cause problems in nursing babies. However, it may be necessary for you to stop breast-feeding temporarily after receiving a radiopaque agent. Be sure you have discussed this with your doctor.

Children
Children, especially those with other medical problems, may be especially sensitive to the effects of radiopaque agents. This may increase the chance of side effects.

Older adults
Elderly people are especially sensitive to the effects of radiopaque agents. This may increase the chance of side effects.

Other medical problems
The presence of other medical problems may affect the use of radiopaque agents. Make sure you tell your doctor if you have any other medical problems, especially:


 * Asthma, hay fever, or other allergies (history of)—If you have a history of these conditions, the risk of having a reaction, such as an allergic reaction to the radiopaque agent, is greater


 * Type 2 diabetes mellitus — There is a greater risk of having kidney problems


 * High blood pressure (severe) or


 * Pheochromocytoma (PCC)—Injection of the radiopaque agent may cause a dangerous rise in blood pressure


 * Kidney disease (severe)—More serious kidney problems may develop; also, the radiopaque agent may build up in the body and cause side effects


 * Liver disease—The radiopaque agent may build up in the body and cause side effects


 * Multiple myeloma (bone cancer)—Serious kidney problems may develop in patients with this condition


 * Overactive thyroid — A sudden increase in symptoms, such as fast heartbeat or palpitations, unusual tiredness or weakness, nervousness, excessive sweating, or muscle weakness may occur


 * Sickle cell disease — The radiopaque agent may promote the formation of abnormal blood cells

Preparation for This Test
Your doctor may have special instructions for you in preparation for your test. He or she might prescribe a special diet or use of a laxative, depending on the type of test. If you have not received such instructions or if you do not understand them, check with your doctor in advance.

For some tests your doctor may tell you not to eat for several hours before having the test. This is to prevent any food from coming back up and entering your lungs during the test. You may be allowed to drink small amounts of clear liquids; however, check first with your doctor.

Precautions After Having This Test
Make sure your doctor knows if you are planning to have any thyroid tests in the near future. Even after several weeks or months the results of the thyroid test may be affected by the iodine in this agent.

Side Effects of This Medicine
Along with their needed effects, radiopaque agents can sometimes cause serious effects such as severe allergic reactions or heart problems. These effects may occur almost immediately or a few minutes after the radiopaque agent is given. Although these serious side effects appear only rarely, your health care professional will be prepared to give you immediate medical attention if needed. If you have any questions about this, check with your doctor.

Check with your doctor as soon as possible if the following side effects occur:

Rare
Hallucinations (seeing hearing, or feeling things that are not there); paralysis of one side of body or of legs and arms

Other side effects may occur that usually do not need medical attention. These side effects may go away as your body adjusts to this agent. However, check with your doctor if any of the following side effects continue or are bothersome:

Less common
Diarrhea or laxative effect

More common
Unusual warmth and flushing of skin

Less common
Chills; dizziness or lightheadedness; headache; nausea or vomiting; pain or burning at the place of injection; sweating; unusual or metallic taste; unusual thirst

More common
Backache; dizziness; headache (mild to moderate); nausea and vomiting (mild to moderate); stiffness of neck

Less common or rare
Difficult urination; drowsiness; headache (severe); increased sensitivity of eyes to light; increased sweating; loss of appetite; ringing or buzzing in ears; unusual tiredness or weakness