Probenecid

PROBENECID- probenecid tablet, film coated Marlex Pharmaceuticals Inc.

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Probenecid Tablets, USP

Probenecid Tablets, USP 500 mg

Rx only

Probenecid is a uricosuric and renal tubular transport blocking agent.

The chemical name for probenecid is 4-[(dipropylamino) sulfony1] benzoic acid. It has the following structural formula:

the following structural formula for probenecid is 4-[(dipropylamino) sulfony1] benzoic acid.

Probenecid, USP is a white or nearly white, fine, crystalline powder. Probenecid is soluble in dilute alkali, in alcohol, in chloroform, and in acetone; it is practically insoluble in water and in dilute acids.

Each tablet for oral administration contains 500 mg of probenecid and the following inactive ingredients: Microcrystalline cellulose, corn starch, sodium starch glycolate, povidone, colloidal silicon dioxide, magnesium stearate, sodium lauryl sulfate, polyvinyl alcohol, titanium dioxide, polyethylene glycol, talc, D&C Yellow #10 Aluminum Lake, FD&C Yellow #6 Aluminum Lake, and FD&C Blue #2 Aluminum Lake.

Probenecid is a uricosuric and renal tubular blocking agent. It inhibits the tubular reabsorption of urate, thus increasing the urinary excretion of uric acid and decreasing serum urate levels. Effective uricosuria reduces the miscible urate pool, retards urate deposition, and promotes resorption of urate deposits.

Probenecid inhibits the tubular secretion of penicillin and usually increases penicillin plasma levels by any route the antibiotic is given. A 2-fold to 4-fold elevation has been demonstrated for various penicillins.

Probenecid also has been reported to inhibit the renal transport of many other compounds including aminohippuric acid (PAH), aminosalicylic acid (PAS), indomethacin, sodium iodomethamate and related iodinated organic acids, 17 –ketosteroids, pantothenic acid, phenolsulfonphthalein (PSP), sulfonamides, and sulfonylureas. See also Drug Interactions.

Probenecid decreases both hepatic and renal excretion of sulfobromophtalein (BSP). The tubular reabsorption of phosphorus is inhibited in hypoparathyroid but not in euparathyroid individuals.

Probenecid does not influence plasma concentrations of salicylates, nor the excretion of streptomycin, chloramphenicol, chlortetracycline, oxytetracycline, or neomycin.

Probenecid tablets are indicated for the treatment of the hyperuricemia associated with gout and gouty arthritis. As an adjuvant to therapy with penicillin or with ampicillin, methicillin, oxacillin, cloxacillin, or nafcillin, for elevation and prolongation of plasma levels by whatever route the antibiotic is given.

Hypersensitivity to probenecid. Children under 2 years of age.

Not recommended in persons with known blood dyscrasias or uric acid kidney stones. Therapy with probenecid should not be started until an acute gouty attack has subsided.

Exacerbation of gout following therapy with probenecid may occur; in such cases colchicine or other appropriate therapy is advisable.

Probenecid increases plasma concentrations of methotrexate in both animals and humans. In animal studies, increased methotrexate toxicity has been reported. If probenecid is given with methotrexate, the dosage of methotrexate should be reduced and serum levels may need to be monitored.

In patients on probenecid the use of salicylates in either small or large doses is contraindicated because it antagonizes the uricosuric action of probenecid. The biphasic action of salicylates in the renal tubules accounts for the so-called “paradoxical effect” of uricosuric agents. In patients on probenecid who require a mild analgesic agent the use of acetaminophen rather than small doses of salicylates would be preferred.

Rarely, severe allergic reactions and anaphylaxis have been reported with the use of probenecid. Most of these have been reported to occur within several hours after re-administration following prior usage of the drug.

The appearance of hypersensitivity reactions requires cessation of therapy with probenecid.

The following adverse reactions have been observed and within each category are listed in order of decreasing severity.

Central Nervous System: headache, dizziness.

Metabolic: precipitation of acute gouty arthritis

Gastrointestinal: hepatic necrosis, vomiting, nausea, anorexia, sore gums.

Genitourinary: nephrotic syndrome, uric acid stones with or without hematuria, renal colic, costovertebral pain, and urinary frequency.

Hypersensitivity: anaphylaxis, fever, urticaria, pruritus

Hematologic: aplastic anemia, leukopenia, hemolytic anemia which in some patients could be related to genetic deficiency of glucose -6- phosphate dehydrogenase in red blood cells, anemia.

Integumentary: dermatitis, alopecia, flushing.

Gout:

Therapy with probenecid should not be started until an acute gouty attack has subsided. However, if an acute attack is precipitated during therapy, probenecid may be continued without changing the dosage, and full therapeutic dosage of colchicine, or other appropriate therapy, should be given to control the acute attack.

The recommended adult dosage is 250 mg (½ probenecid tablet), twice a day for one week, followed by 500 mg (1 tablet) twice a day thereafter.

Some degree of renal impairment may be present in patients with gout. A daily dosage of 1000 mg may be adequate. However, if necessary, the daily dosage may be increased by 500 mg increments every 4 weeks within tolerance (and usually not above 2000 mg per day) if symptoms of gouty arthritis are not controlled or the 24 hour uric acid excretion is not above 700 mg. As noted, probenecid may not be effective in chronic renal insufficiency particularly when the glomerular filtration rate is 30 mg mL/minute or less.

Gastric intolerance may be indicative of over dosage, and may be corrected by decreasing the dosage.

As uric acid tends to crystallize out of an acid urine, a liberal fluid intake is recommended, as well as sufficient sodium bicarbonate (3 to 7.5 g daily ), or potassium citrate (7.5 g daily) to maintain an alkaline urine (see PRECAUTIONS).

Alkalization of the urine is recommended until the serum urate level returns to normal limits and tophaceous deposits disappear, i.e., during the period when urinary excretion of uric acid is at high level. Thereafter, alkalization of the urine and the usual restriction of purine-producing foods may be somewhat relaxed.

Probenecid should be continued at the dosage that will maintain normal serum urate levels. When acute attacks have been absent for 6 months or more and serum urate levels remain within normal limits, the daily dosage may be decreased by 500 mg every 6 months. The maintenance dosage should not be reduced to the point where serum urate levels tend to rise.

Probenecid and Penicillin Therapy (General):

Adults: The recommended dosage is 2000 mg (4 tablets of probenecid) daily in divided doses. This dosage should be reduced in older patients in whom renal impairment may be present.

Children: 2-14 years of age:

Initial dose: 25 mg/kg body weight (or 0.7 g/square meter body surface).

Maintenance Dose: 40 mg/kg body weight (or 1.2 g/square meter body surface) per day, divided into 4 doses.

For children weighing more than 50 kg (110lb) the adult dosage is recommended.

Probenecid is contraindicated in children under 2 years of age.

The PSP excretion test may be used to determine the effectiveness of probenecid in retarding penicillin excretion and maintaining therapeutic levels. The renal clearance of PSP is reduced to about one-fifth the normal rate when dosage of probenecid is adequate.

Penicillin Therapy (Gonorrhea) ¹

1 Recommended by the Center of Disease Control, U.S Department of Health and Human Services, Public Health Service (Morbidity and Mortality Weekly Report Supplement, Volume 34, Number 4S, October 18, 1985).

In uncomplicated gonococcal infections in men and women (urethral, cervical, rectal), 1 g of probenecid should be given orally with 4.8 million units of aqueous procaine penicillin G² (given IM), or 3 g of amoxicillin² (given orally), or 3.5 g of ampicillin² (given orally).

For further guidance, see CDC recommendations for definition of regimens of choice, alternative regimens, treatment of hypersensitive patients, and other aspects of therapy.

2 See package circulators of manufacturers for detailed information about CONTRAINDICATIONS , WARNINGS , PRECAUTIONS , and ADVERSE REACTIONS .

Probenecid Tablets, USP are available containing 500 mg of Probenecid, USP.

The tablets are capsule shaped, film-coated yellow, debossed LCI on one side and 1367 on the other side. They are available as follows:

NDC 10135-0541-01 bottles of 100 tablets

NDC 10135-0541-10 bottles of 1000 tablets

STORE AT 20˚ to 25˚C (68˚-77˚F)[See USP Controlled Room Temperature]

PROTECT FROM LIGHT.

Dispense in a well closed, light-resistant container using a child-resistant closure as defined in the USP.

MANUFACTURED BY LANNETT COMPANY, INC. PHILADELPHIA, PA 19136

DISTRIBUTED BY

MARLEX PHARMACEUTICALS, INC. NEW CASTLE, DE 19720

Made in the USA

Rev.1 10/14LAN

NDC 10135-541-01

Probenecid

Tablets, USP

500 mg

100 Tablets

Rx Only

Probenecid-100

NDC 10135-541-10

Probenecid

Tablets, USP

500 mg

1000 Tablets

Rx Only

Probenecid-1000