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sulfadiazine
generic
Adult Dosing .
Dosage forms: TAB: 500 mg
rheumatic fever prophylaxis, secondary
- [1000 mg PO qd]
toxoplasmosis
- [treatment, <60 kg]
- Dose: 1000 mg PO q6h for at least 6wk; Info: give with pyrimethamine, leucovorin
- [treatment, >60 kg]
- Dose: 1500 mg PO q6h for at least 6wk; Info: give with pyrimethamine, leucovorin
- [maintenance tx, <60 kg (off-label)]
- Dose: 2000 mg/day PO divided bid-qid; Info: give with pyrimethamine, leucovorin
- [maintenance tx, >60 kg (off-label)]
- Dose: 4000 mg/day PO divided bid-qid; Info: give with pyrimethamine, leucovorin
renal dosing
- [toxoplasmosis tx]
- CrCl 10-50: 1000-1500 mg q12h; CrCl <10: 1000-1500 mg q24h
- HD: 1000-1500 mg q24h, on dialysis days administer after dialysis; supplement not defined; PD: not defined
- [all other indications]
- renal impairment: not defined, caution advised
- HD/PD: not defined
hepatic dosing
- [see below]
- hepatic impairment: not defined, caution advised
Peds Dosing .
- Dosage forms: TAB: 500 mg
rheumatic fever prophylaxis, secondary
- [2 mo and older, <30 kg]
- Dose: 500 mg PO qd
- [2 mo and older, >30 kg]
- Dose: 1000 mg PO qd
toxoplasmosis
- [treatment, congenital infection]
- Dose: 100 mg/kg/day PO divided q12h x12mo; Info: give with pyrimethamine, leucovorin
- [treatment, acquired infection]
- Dose: 100-200 mg/kg/day PO divided q6h for at least 6wk; Max: 1000-1500 mg/dose; Info: give with pyrimethamine, leucovorin
- [suppressive therapy]
- Dose: 85-120 mg/kg/day PO divided q6-12h; Max: 2000-4000 g/day; Info: give with pyrimethamine, leucovorin
renal dosing
- [see below]
- renal impairment: not defined, caution advised
- HD/PD: not defined
hepatic dosing
- [see below]
- hepatic impairment: not defined, caution advised
Contraindications / Cautions .
- hypersensitivity to drug or ingredient
- hypersensitivity to sulfonamides
- patients <2 mo (except congenital toxoplasmosis use)
- porphyria
- avoid: sun exposure
- avoid: UV light exposure, artificial
- caution: hepatic impairment
- caution: renal impairment
- caution: G6PD deficiency
- caution: volume depletion
- caution: antibiotic-associated colitis history, recent
- caution: lupus erythematosus
Drug Interactions .
Overview
sulfadiazine
sulfonamide
- CYP2C9 inhibitor, weak
- affected by altered gastrointestinal motility
- alters GI flora
- hypoglycemic effects
- impairs immunomodulatory bacterial infective agent
- methemoglobinemia
- photosensitivity
- urine pH sensitive
Contraindicated
- lidocaine topical
- methenamine
- prilocaine topical
Avoid/Use Alternative
- aminolevulinic acid topical
- BCG live intravesical
- bosentan
- bremelanotide
- chloroprocaine
- cholera vaccine, live
- fecal microbiota, live
- methadone
- methotrexate
- porfimer
- primaquine
- tretinoin topical
- typhoid vaccine, live
Monitor/Modify Tx
- aficamten
- celecoxib
- cyclosporine
- deuruxolitinib
- diclofenac
- exenatide
- flutamide
- fluvastatin
- fosphenytoin
- glimepiride
- glipizide
- glyburide
- insulin
- lixisenatide
- nateglinide
- nitric oxide
- nitrite
- phenytoin
- pramlintide
- repaglinide
- torsemide
- warfarin
Caution Advised
- acitretin
- articaine
- benzocaine topical
- bupivacaine
- bupivacaine liposomal
- butamben
- dapsone
- dapsone topical
- dulaglutide
- isosorbide dinitrate
- isosorbide mononitrate
- lactulose
- lidocaine
- liraglutide
- mepivacaine
- methoxsalen
- metoclopramide
- nitrofurantoin
- nitroglycerin
- nitroprusside
- probenecid
- procaine
- rasburicase
- resorcinol topical
- ropivacaine
- sodium picosulfate
- sulfamethoxazole
- sulfasalazine
- tafenoquine
- tetracaine
- tirzepatide
- verteporfin
Adverse Reactions .
Serious Reactions
- anaphylaxis
- Stevens-Johnson syndrome
- toxic epidermal necrolysis
- photosensitivity
- hemolytic anemia
- aplastic anemia
- thrombocytopenia
- leukopenia
- methemoglobinemia
- hepatitis
- acute renal failure
- kernicterus (neonates)
- C. difficile-associated diarrhea
- lupus erythematosus
- hypoglycemia
Common Reactions
- fever
- dizziness
- headache
- nausea
- vomiting
- diarrhea
- rash
- pruritus
- photosensitivity
- crystalluria
- hematuria
Safety/Monitoring .
Therapeutic Drug Levels
Serious infections: 120-150 mcg/mL (sulfonamide, free); Toxic Levels: >200 mcg/mL; Time to Steady State: 50h; Info: may not be routinely available
Monitoring Parameters
CBC, urinalysis frequently; serum drug levels if serious infection
Look/Sound-Alike Drug Names
sulfADIAZINE confused with: Azulfidine; sulfasalazine
Pregnancy/Lactation .
Pregnancy
Clinical Summary
weigh risk/benefit during pregnancy, especially in 3rd trimester; no human data available, though risk of kernicterus near term based on human data with other sulfonamides
Lactation
Clinical Summary
weigh risk/benefit while breastfeeding; theoretical risk of hyperbilirubinemia in high-risk infants based on drug's mechanism of action; no human data available to assess effects on milk production
Pharmacology .
Metabolism: for sulfadiazine: liver; CYP450: unknown
Excretion: for sulfadiazine: urine (primarily unchanged); Half-life: 10h, 34h (renal failure)
Subclass: Antiparasitics ; Folate Antagonists, Antimicrobial ; Sulfonamides
Mechanism of Action
for sulfadiazine: competes with para-aminobenzoic acid (PABA), inhibiting folic acid synthesis
Formulary .
No Formulary Selected
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