Probenecid belongs to the class of medications called uricosurics. It is used to treat and prevent gout. It is not useful for treatment of a gout attack that is currently taking place.

It may also be used to increase the levels of certain types of antibiotics in the blood. Probenecid acts by decreasing levels of uric acid, which causes gout, in the blood. It acts on the kidney to pass uric acid in the urine. Probenecid also acts on the kidney to prevent certain antibiotics, such as penicillin, from being passed in the urine.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. As well, some forms of this medication may not be used for all of the conditions discussed here. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The recommended adult dose of probenecid for gout is 250 mg twice a day for one week, followed by 500 mg twice a day after that. The maximum dose is usually 2 g daily.

When used to increase the levels of certain antibiotics, the usual dose is 1,000 mg, given as a single dose or once daily, depending on the antibiotic.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children.

Do not take this medication if you:

• are allergic to probenecid or any ingredients of the medication
• are having an acute gout attack (wait until the attack has gone away)
• have known blood disorders
• have or have had a peptic (stomach or intestine) ulcer
• have uric acid kidney stones or are at risk of uric acid kidney stones (people at risk include those undergoing chemotherapy or radiation for cancer or those with kidney problems)

Do not give probenecid to children under 2 years of age.

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• dizziness
• flushing or redness of face (occurring without any signs of an allergic reaction)
• frequent urge to urinate
• headache
• joint pain, redness, or swelling
• loss of appetite
• nausea or vomiting (mild)
• sore gums

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

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

Stop taking the medication and seek immediate medical attention if any of the following occur:

• changes in the skin colour of the face occurring together with any of the other side effects listed here
• fast or irregular breathing
• puffiness or swelling of the eyelids or around the eyes
• shortness of breath, troubled breathing, tightness in chest, or wheezing
• skin rash, hives, or itching occurring together with any of the other side effects listed here

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Allergies: If you have a serious allergic reaction to probenecid, you will need to stop taking this medication.

Kidney stones: Probenecid can increase the risk of kidney stones. Take this medication with plenty of fluids to help reduce the risk.

Use of salicylates: People who take this medication should not use salicylates (e.g., ASA) in either small or large doses because they reduce the effects of probenecid. People who take probenecid who require a mild pain reliever should use acetaminophen rather than small doses of salicylates.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: It is not known if probenecid passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

There may be an interaction between probenecid and any of the following:

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.