Some commonly used names are phenol red; PSP.

• Diagnostic aid, renal function
• Diagnostic aid, residual bladder urine

Phenolsulfonphthalein (fee-nole-sul-fon-THAY-leen) is used as a test to help diagnose problems or disease of the kidneys. This test determines how well your kidneys are working.

Phenolsulfonphthalein passes out of the body almost entirely in the urine. Measuring the amount of phenolsulfonphthalein in the urine can help the doctor determine if the kidneys are working properly.

How test is done: After you have emptied your bladder, phenolsulfonphthalein will be given by injection. Then you will be asked to empty your bladder into a container one or more times after the medicine is given. The amount of this medicine in your urine will be measured. Then the results of the test will be studied. The way the phenolsulfonphthalein test is done may be different for different patients. Some patients may have the phenolsulfonphthalein injected into a vein, others, into a muscle.

It is very important that you empty the bladder completely and collect all the urine when you are asked to do so. If any urine is left behind or lost, it will change the results of the test.

Phenolsulfonphthalein is to be used only under the supervision of a doctor. It is available in the following dosage form:

Parenteral
• Injection (U.S.)

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 phenolsulfonphthalein, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to phenolsulfonphthalein. Also tell your doctor if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Studies have not been done in either humans or animals.

Breast-feeding—It is not known whether phenolsulfonphthalein passes into the breast milk. This medicine has not been reported to cause problems in nursing babies.

Children—Although there is no specific information comparing use of phenolsulfonphthalein in children with use in other age groups, phenolsulfonphthalein is not expected to cause different side effects or problems in children than it does in adults.

Older adults—Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults. Although there is no specific information comparing use of phenolsulfonphthalein in the elderly with use in other age groups, this medicine is not expected to cause different side effects or problems in older people than it does in younger adults.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking phenolsulfonphthalein, it is especially important that your health care professional know if you are taking any of the following:

• Aspirin or other salicylates or
• Atropine or
• Diuretics (water pills) or
• Penicillins or
• Probenecid (e.g., Benemid) or
• Sulfinpyrazone (e.g., Anturane) or
• Sulfonamides (sulfa medicine)—Use of any of these medicines at the same time as phenolsulfonphthalein may affect the test results

• Gout or
• Liver disease or
• Multiple myeloma (a kind of cancer)—These conditions may affect how fast the body gets rid of the phenolsulfonphthalein

• Heart or blood vessel disease or
• Kidney disease (severe)—Patients with these conditions are at greater risk of becoming ill because of the large amount of liquids that must be taken for this test

Your doctor will ask you to drink a certain amount of water a little while before this test is done. Follow your doctor's instructions carefully . Otherwise, this test may not work and may have to be done again.

Along with its needed effects, a medicine may cause some unwanted effects. Although this medicine usually does not cause any side effects, tell your health care professional immediately if you notice wheezing or skin rash or itching shortly after it is given.

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.