In the U.S.—

Other commonly used names are methionine; DL-methionine.

• Acidifier, urinary
• Antidote, to acetaminophen overdose

Racemethionine ( race-e-me-THYE-oh-neen) is used to make the urine more acidic. Making the urine more acidic helps to relieve skin irritation in incontinent (loss of bladder control) adults and diaper rash in infants. This medicine also helps to control strong urine odor.

Racemethionine is available only with your doctor's prescription, in the following dosage forms:

Oral
• Capsules (U.S.)
• Oral solution (U.S.)
• 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 racemethionine, the following should be considered:

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

Diet—Make certain your health care professional knows if you are on any special diet, such as a low-protein diet.

Pregnancy—Racemethionine has not been shown to cause birth defects or other problems in humans.

Breast-feeding—It is not known whether racemethionine passes into breast milk. Although most medicines pass into breast milk in small amounts, many of them may be used safely while breast-feeding. Mothers who are taking this medicine and who wish to breast-feed should discuss this with their doctor.

Children—This medicine has been tested in children and, in effective doses, has not been shown to cause different side effects or problems 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 racemethionine 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.

• Acidosis (metabolic) or
• Liver disease—Use of racemethionine may make these conditions worse

You should not take more of this medicine, or take it more often, than your doctor ordered. You should also make sure that you get enough protein in your diet. This is especially important in infants. Infants who get too much racemethionine and not enough protein may not gain weight as they should. If you have any questions about this, ask your health care professional.

Take racemethionine with, or just after, meals.

For patients taking racemethionine capsules:

• If you are unable to swallow the capsule, the contents may be added to juice, water, or warm milk or infant formula.

For patients taking racemethionine oral solution:

• Use a specially marked measuring spoon or other device to measure each dose accurately. The average household teaspoon may not hold the right amount of liquid.

Dosing—

The dose of racemethionine 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 racemethionine. If your dose is different, do not change it unless your doctor tells you to do so.

The number of capsules or tablets or teaspoonfuls of solution that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on your medical condition .

• For making urine more acidic:
  • For oral dosage form (capsules):
    • Adults and teenagers—The usual dose is 200 milligrams (mg) three or four times a day.
    • Children—The usual dose is the contents of 1 capsule (200 mg) added to a warm bottle of milk or formula in the evening, or added to a glass of juice or water.
  • For oral dosage form (oral solution):
    • Adults and children older than 14 months of age—The usual dose is 2⅔ teaspoonfuls (200 mg) three or four times a day.
    • Children 6 to 14 months of age—The usual dose is 1 teaspoonful (75 mg) four times a day for three to five days.
    • Children 2 to 6 months of age—The usual dose is 1 teaspoonful (75 mg) three times a day for three to five days.
    • Children up to 2 months of age—Dose must be determined by your doctor.
  • For oral dosage form (tablets):
    • Adults and teenagers—The usual dose is 500 mg three or four times a day.
    • Children—The capsule or oral solution is the recommended dosage form for this age group.

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 the capsule or tablet form of this medicine in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Keep the medicine from freezing. Do not refrigerate.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

If your rash has not improved after 10 days, check with your doctor.

Along with its needed effects, a medicine may cause some unwanted effects. Side effects that may occur during racemethionine therapy usually do not need medical attention. They may go away during treatment as your body adjusts to the medicine. Check with your doctor if any of the following side effects continue or are bothersome:

• More common
  • Drowsiness;  nausea and vomiting 
  
  

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

Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although this use is not included in product labeling, racemethionine may be used to treat acetaminophen poisoning when the preferred medicine for treatment is not available.

Other than the above information, there is no additional information relating to proper use, precautions, or side effects for this use.