If probenecid upsets your stomach, it may be taken with food. If this does not work, an antacid may be taken. If stomach upset (nausea, vomiting, or loss of appetite) continues, check with your doctor.

For patients taking probenecid for gout:

• After you begin to take probenecid, gout attacks may continue to occur for a while. However, if you take this medicine regularly as directed by your doctor, the attacks will gradually become less frequent and less painful than before. After you have been taking probenecid for several months, they may stop completely.
• This medicine will help prevent gout attacks but it will not relieve an attack that has already started. Even if you take another medicine for gout attacks, continue to take this medicine also. If you have any questions about this, check with your doctor.

For patients taking probenecid for gout or to help remove uric acid from the body:

• When you first begin taking probenecid, the amount of uric acid in the kidneys is greatly increased. This may cause kidney stones or other kidney problems in some people. To help prevent this, your doctor may want you to drink at least 10 to 12 full glasses (8 ounces each) of fluids each day, or to take another medicine to make your urine less acid. It is important that you follow your doctor's instructions very carefully.

Dosing

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

• For treating gout or removing uric acid from the body:
  • Adults: 250 mg (one-half of a 500-mg tablet) two times a day for about one week, then 500 mg (one tablet) two times a day for a few weeks. After this, the dose will depend on the amount of uric acid in your blood or urine. Most people need 2, 3, or 4 tablets a day, but some people may need higher doses.
  • Children: It is not likely that probenecid will be needed to treat gout or to remove uric acid from the body in children. If a child needs this medicine, however, the dose would have to be determined by the doctor.
• For helping antibiotics work better:
  • Adults: The amount of probenecid will depend on the condition being treated. Sometimes, only one dose of 2 tablets is needed. Other times, the dose will be 1 tablet four times a day.
  • Children: The dose will have to be determined by the doctor. It depends on the child's weight, as well as on the condition being treated. Older children and teenagers may need the same amount as adults.

Missed dose

If you are taking probenecid regularly and you miss a dose, take the missed dose as soon as possible. However, if you do not remember until it is almost time for the 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 this medicine 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.

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 probenecid, the following should be considered:

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

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

Breast-feeding Probenecid has not been reported to cause problems in nursing babies.

Children Probenecid has been tested in children 2 to 14 years of age for use together with antibiotics. It has not been shown to cause different side effects or problems than it does in adults. Studies on the effects of probenecid in patients with gout have been done only in adults. Gout is very rare in children.

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. There is no specific information comparing use of probenecid in the elderly with use in other age groups.

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 probenecid, it is especially important that your health care professional know if you are taking any of the following:

• Antineoplastics (cancer medicine) The chance of serious side effects may be increased

• Aspirin or other salicylates These medicines may keep probenecid from working properly for treating gout, depending on the amount of aspirin or other salicylate that you take and how often you take it

• Heparin Probenecid may increase the effects of heparin, which increases the chance of side effects

• Indomethacin (e.g., Indocin) or
• Ketoprofen (e.g., Orudis) or
• Methotrexate (e.g., Mexate) Probenecid may increase the blood levels of these medicines, which increases the chance of side effects

• Medicine for infection, including tuberculosis or virus infection Probenecid may increase the blood levels of many of these medicines. In some cases, this is a desired effect and probenecid may be used to help the other medicine work better. However, the chance of side effects is sometimes also increased

• Nitrofurantoin (e.g., Furadantin) Probenecid may keep nitrofurantoin from working properly

• Zidovudine (e.g., AZT, Retrovir) Probenecid increases the blood level of zidovudine and may allow lower doses of zidovudine to be used. However, the chance of side effects is also increased

• Blood disease or
• Cancer being treated by antineoplastics (cancer medicine) or radiation (x-rays) or
• Kidney disease or stones (or history of) or
• Stomach ulcer (history of) The chance of side effects may be increased