Classifications: sulfonamide antibiotic; Therapeutic: antibiotic, sulfonamide
Pregnancy Category: C
500 mg tablets
Short-acting sulfonamide, slightly less soluble than sulfisoxazole. Exerts bacteriostatic effect by interfering with bacterial
utilization of PABA, thereby inhibiting folic acid biosynthesis required for bacterial growth.
Effective against a wide range of gram-positive and gram-negative microorganisms.
Used in combination with pyrimethamine for treatment of cerebral toxoplasmosis and chloroquine-resistant malaria.
Hypersensitivity to sulfonamides or to any ingredients in the formulation; porphyria; pregnancy (category C); at term pregnancy;
Application of lotion to denuded or debrided skin; dehydration; hepatic disease; impaired renal function.
Route & Dosage
|Mild to Moderate Infections
Adult: PO Loading Dose 24 g loading dose PO Maintenance Dose 24 g/d in 46 divided doses
Child: PO Loading Dose >2 mo, 75 mg/kg PO Maintenance Dose 150 mg/kg/d in 46 divided doses (max: 6 g/d)
Rheumatic Fever Prophylaxis
Adult: PO <30 kg, 500 mg/d; >30 kg, 1 g/d
Adult: PO 28 g/d divided q6h
Child (>2 mo): PO 100200 mg/kg/d divided q6h
Neonate: PO 50 mg/kg q12h x 12 mo
- Maintain sufficient fluid intake to produce urinary output of at least 1500 mL/24 h for children between 3000 and 4000 mL/24
h for adults. Concomitant administration of urinary alkalinizer may be prescribed to reduce possibility of crystalluria
and stone formation.
- Store in tight, light-resistant containers.
Adverse Effects (≥1%)CNS:
Headache, peripheral neuritis
, peripheral neuropathy
, tinnitus, hearing loss, vertigo, insomnia
, drowsiness, mental depression
acute psychosis, ataxia, convulsions, kernicterus (newborns). GI: Nausea, vomiting, diarrhea,
abdominal pains, hepatitis
Acute hemolytic anemia
(especially in patients with G6PD deficiency), aplastic anemia,
methemoglobinemia, agranulocytosis, thrombocytopenia
, eosinophilia, hypoprothrombinemia. Body as a Whole:
, allergic myocarditis, serum
sickness, anaphylactoid reactions,
lymphadenopathy, local reaction following IM injection, fixed drug eruptions, diuresis, overgrowth of nonsusceptible organisms,
LE phenomenon. Skin:
Pruritus, urticaria, rash, erythema multiforme
including Stevens-Johnson syndrome, exfoliative dermatitis, alopecia
, photosensitivity, vascular lesions. Urogenital: Crystalluria,
hematuria, proteinuria, anuria, toxic nephrosis, reduction in sperm count. Metabolic: Goiter
. Special Senses: Conjunctivitis
, conjunctival or scleral infection
, retardation of corneal healing (ophthalmic ointment).
-containing local anesthetics
may antagonize sulfa's effects; oral anticoagulants
potentiate hypoprothrombinemia; may potentiate sulfonylurea
. May decrease concentrations of cyclosporine;
may increase levels of phenytoin.
Readily absorbed from GI tract. Peak:
36 h. Distribution:
Distributed to most tissues, including CSF; crosses placenta. Metabolism:
In liver. Elimination:
Assessment & Drug Effects
- Lab tests: Baseline and periodic urine C&S to determine drug effectiveness; with long-term therapy, CBC, Hct, and Hgb.
- Monitor hydration status.
Patient & Family Education
- Take drug exactly as prescribed. Do not alter schedule or dose; take total amount prescribed unless physician changes the
- Drink fluids liberally unless otherwise directed.
- Report early signs of blood dyscrasias (sore throat, pallor, fever) promptly to the physician.