In the U.S.—

• Antiurolithic, cystine calculi

Tiopronin (tye-oh-PRO-nin) is used to prevent kidney stones, which may develop due to too much cystine in the urine (cystinuria). This medicine works by removing the extra cystine from the body.

In addition to the helpful effects of this medicine, it has side effects that can be very serious. Before you take tiopronin, be sure that you have discussed its use with your doctor.

Tiopronin is available only with your doctor's prescription, in the following dosage form:

Oral
• Tablets (U.S.)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For tiopronin, the following should be considered:

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

Diet—It is important that you follow any special instructions from your doctor, such as following a low-methionine diet. Methionine is found in animal proteins such as milk, eggs, cheese, and fish. Also, make certain your health care professional knows if you are on any special diet, such as a low-sodium or low-sugar diet.

Pregnancy—Studies have not been done in humans. However, studies in animals have shown that tiopronin may cause problems during pregnancy and harmful effects on the fetus.

Breast-feeding—Tiopronin may pass into the breast milk. This medicine is not recommended during breast-feeding because it may cause unwanted effects in nursing babies.

Children—Although there is no specific information comparing use of tiopronin in children with use in other age groups, this medicine 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 or if they cause different side effects or problems in older people. Although there is no specific information comparing the use of tiopronin 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. Tell your health care professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.

• Blood problems (or a history of) or
• Kidney disease (or a history of) or
• Liver disease—Tiopronin may make these conditions worse

Take this medicine on an empty stomach (at least 30 minutes before meals or 2 hours after meals).

You should drink 2 full glasses (8 ounces each) of water with each meal and at bedtime. You should also drink another 2 full glasses during the night.

It is important that you follow any special instructions from your doctor, such as following a low-methionine diet. Methionine is found in animal proteins such as milk, eggs, cheese, and fish. If you have any questions about this, check with your doctor.

Take this medicine regularly as directed. Do not stop taking it without first checking with your doctor, since stopping the medicine and then restarting it may increase the chance of side effects.

Dosing—

The dose of tiopronin will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of tiopronin. If your dose is different, do not change it unless your doctor tells you to do so.

• For oral dosage form (tablets):
  • To prevent kidney stones:
    • Adults—To start, 800 milligrams (mg) a day, divided into three doses. Your doctor may change your dose if needed.
    • Children up to 9 years of age—Dose must be determined by your doctor.
    • Children 9 years and older—Dose is based on body weight and must be determined by your doctor. The usual dose to start is 15 mg per kilogram (kg) (6.8 mg per pound) of body weight a day, divided into three doses. Your doctor may change your dose if needed.

Missed dose—

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage—

To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

Your doctor should check your progress at regular visits to make sure that this medicine is working properly and does not cause unwanted effects.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

• More common
  • Yellow skin or eyes 
  
  

• Less common
  • Muscle pain;  sore throat and fever;  unusual bleeding or bruising 
  
  

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

• More common
  • Pain, swelling, or tenderness of the skin;  skin rash, hives or itching;  ulcers or sores in mouth  
  
  

• Less common
  • Bloody or cloudy urine;  chills;  difficulty in breathing;  high blood pressure;  hoarseness;  joint pain;  swelling of feet or lower legs;  tenderness of glands;  unusual bleeding  
  
  

• Rare
  • Chest pain;  cough;  difficulty in chewing, talking, or swallowing;  double vision;  general feeling of discomfort, illness, or weakness;  muscle weakness;  spitting up blood;  swelling of lymph glands 
  
  

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

• More common
  • Abdominal or stomach pain;  bloating or gas;  diarrhea or soft stools;  loss of appetite;  nausea and vomiting;  warts;  wrinkling or peeling or unusually dry skin 
  
  

• Less common
  • Changes in taste or smell 
  
  

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