sulfADIAZINE Tablets, USP

Sulfadiazine is an oral sulfonamide antibacterial agent.

Each tablet, for oral administration, contains 500 mg sulfadiazine. In addition, each tablet contains the following inactive ingredients: croscarmellose sodium, docusate sodium, microcrystalline cellulose, povidone, sodium benzoate, sodium starch glycolate and stearic acid.

Sulfadiazine occurs as a white or slightly yellow powder. It is odorless or nearly so and slowly darkens on exposure to light. It is practically insoluble in water and slightly soluble in alcohol. The chemical name of sulfadiazine is N¹-2-pyrimidinylsulfanilamide. The molecular formula is C₁₀H₁₀N₄O₂S. It has a molecular weight of 250.27. The structural formula is shown below:

Most sulfonamides slowly darken on exposure to light.

The systemic sulfonamides are bacteriostatic agents having a similar spectrum of activity. Sulfonamides competitively inhibit bacterial synthesis of folic acid (pteroylglutamic acid) from aminobenzoic acid. Resistant strains are capable of utilizing folic acid precursors or preformed folic acid.

Sulfonamides exist in the blood in 3 forms – free, conjugated (acetylated and possibly others) and protein bound. The free form is considered to be the therapeutically active one.

Sulfadiazine given orally is readily absorbed from the gastrointestinal tract. After a single 2 g oral dose, a peak of 6.04 mg/100 mL is reached in 4 hours; of this, 4.65 mg/100 mL is free drug.

When a dose of 100 mg/kg of body weight is given initially and followed by 50 mg/kg every 6 hours, blood levels of free sulfadiazine are about 7 mg/100mL. Protein binding is 38% to 48%. Sulfadiazine diffuses into the cerebrospinal fluid; free drug reaches 32% to 65% of blood levels and total drug 40% to 60%.

Sulfadiazine is excreted largely in the urine, where concentrations are 10 to 25 times greater than serum levels. Approximately 10% of a single oral dose is excreted in the first 6 hours, 50% within 24 hours and 60% to 85% in 48 to 72 hours. Of the amount excreted in the urine, 15% to 40% is in the acetyl form.

sulfADIAZINE Tablets, USP are indicated in the following conditions:

Chancroid

Trachoma

Inclusion conjunctivitis

Nocardiosis

Urinary tract infections (primarily pyelonephritis, pyelitis and cystitis) in the absence of obstructive uropathy or foreign bodies, when these infections are caused by susceptible strains of the following organisms: Escherichia coli, Klebsiella species, Enterobacter species, Staphylococcus aureus, Proteus mirabilis and P. vulgaris. Sulfadiazine should be used for urinary tract infections only after use of more soluble sulfonamides has been unsuccessful.

Toxoplasmosis encephalitis in patients with and without acquired immunodeficiency syndrome, as adjunctive therapy with pyrimethamine.

Malaria due to chloroquine-resistant strains of Plasmodium falciparum, when used as adjunctive therapy.

Prophylaxis of meningococcal meningitis when sulfonamide-sensitive group A strains are known to prevail in family groups or larger closed populations (the prophylactic usefulness of sulfonamides when group B or C infections are prevalent is not proved and may be harmful in closed population groups).

Meningococcal meningitis, when the organism has been demonstrated to be susceptible.

Acute otitis media due to Haemophilus influenzae, when used concomitantly with adequate doses of penicilin.

Prophylaxis against recurrences of rheumatic fever, as an alternative to penicillin.

H. influenzae meningitis, as adjunctive therapy with parental streptomycin.

IMPORTANT NOTES

In vitro sulfonamide susceptibility tests are not always reliable. The test must be carefully coordinated with bacteriologic and clinical response. When the patient is already taking sulfonamides, follow-up cultures should have aminobenzoic acid added to the culture media.

Currently, the increasing frequency of resistant organisms limits the usefulness of antibacterial agents, including the sulfonamides, especially in the treatment of recurrent and complicated urinary tract infections.

Wide variation in blood levels may result with identical doses. Blood levels should be measured in patients receiving sulfonamides for serious infections. Free sulfonamide blood levels of 5 mg to 15 mg per 100 mL may be considered therapeutically effective for most infections and blood levels of 12 mg to 15 mg per 100 mL may be considered optimal for serious infections. Twenty mg per 100 mL should be the maximum total sulfonamide level, since adverse reactions occur more frequently above this level.

Sulfadiazine is contraindicated in the following circumstances: Hypersensitivity to sulfonamides.

In infants less than 2 months of age (except as adjunctive therapy with pyrimethamine in the treatment of congenital toxoplasmosis).

In pregnancy at term and during the nursing period, because sulfonamides cross the placenta and are excreted in breast milk and may cause kernicterus.

The sulfonamides should not be used for the treatment of group A betahemolytic streptococcal infections. In an established infection, they will not eradicate the streptococcus and, therefore, will not prevent sequelae such as rheumatic fever and glomerulonephritis.

Deaths associated with the administration of sulfonamides have been reported from hypersensitivity reactions, agranulocytosis, aplastic anemia and other blood dyscrasias.

The presence of such clinical signs as sore throat, fever, pallor, purpura or jaundice may be early indications of serious blood disorders.

The frequency of renal complications is considerably lower in patients receiving the more soluble sulfonamides.

SYSTEMIC SULFONAMIDES ARE CONTRAINDICATED IN INFANTS UNDER 2 MONTHS OF AGE except as adjunctive therapy with pyrimethamine in the treatment of congenital toxoplasmosis.

sulfADIAZINE Tablets, USP for oral administration are available as

500 mg

White, unscored, capsule-shaped tablets, debossed “E 757” on one face and supplied as:

NDC 42806-757-60 bottles of 60

Storage

Store at 20° to 25°C (68° to 77°F) [see USP Controlled Room Temperature].

Protect from moisture.

Dispense contents in a tight, light-resistant container as defined in the USP with a child-resistant closure, as required.

KEEP TIGHTLY CLOSED.

KEEP OUT OF THE REACH OF CHILDREN.

To report SUSPECTED ADVERSE REACTIONS, contact Epic Pharma, LLC at 1-888-374-2791 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Distributed by:

Epic Pharma, LLC

Laurelton, NY 11413

Rev. 06-2023-00

MF757REV06/23

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