Description and Brand Names

Drug information provided by: Merative, Micromedex®


Radiopaque agents are drugs used to help diagnose certain medical problems. They contain iodine, which blocks x-rays. Depending on how the radiopaque agent is given, it localizes or builds up in certain areas of the body. The resulting high level of iodine allows the x-rays to make a "picture" of the area.

The areas of the body in which the radiopaque agent localizes will appear white on the x-ray film. This creates the needed distinction, or contrast, between one organ and other tissues. The contrast will help the doctor see any special conditions that may exist in that organ or part of the body.

The local radiopaque agents are used in the diagnosis of:

  • Urinary tract diseases—Diatrizoates, Iohexol, Iothalamate
  • Uterus and fallopian tube diseases—Diatrizoate and Iodipamide, Diatrizoates, Iohexol, Ioxaglate

A catheter or syringe is used to put the solution of the radiopaque agent into the bladder or ureters to help diagnose problems or diseases of the kidneys or other areas of the urinary tract. It may also be placed into the uterus and fallopian tubes to help diagnose problems or disease of those organs. After the test is done, the patient expels most of the solution by urinating (after bladder or ureter studies) or from the vagina (after uterine or fallopian tube studies).

Radiopaque agents are classified by their osmolality (a measure of concentration). There are high- and low-osmolality contrast agents. Low-osmolality agents are newer and more expensive than the high-osmolality ones. For most patients, a high-osmolality contrast agent is a good and safe choice. However, some patients are considered to be at a greater risk of having severe reactions to a radiopaque agent. Patients at risk are those who have had a severe reaction to radiopaque agents in the past. Also, patients with asthma or a history of allergies may be at a greater risk of severe reactions. For these patients, a low-osmolality contrast agent may be chosen. If you have any questions about this, check with the radiologist.

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. Also, for tests of the kidneys and other areas of the urinary tract, the amount of solution to be used depends on the size of the bladder.

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