NEOTRIZINE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NEOTRIZINE (NEOTRIZINE).
Neotrizine contains sulfadiazine, a competitive inhibitor of dihydropteroate synthase, blocking folic acid synthesis in susceptible bacteria.
| Metabolism | Primarily hepatic via acetylation and glucuronidation; CYP450 involvement minimal. |
| Excretion | Renal excretion of unchanged drug accounts for 60-70% of elimination; biliary/fecal elimination accounts for 20-30%, with the remainder as metabolites. |
| Half-life | Terminal elimination half-life is 4-6 hours in adults with normal renal function; in renal impairment, half-life may extend to 12-18 hours requiring dose adjustment. |
| Protein binding | 75-85% bound primarily to albumin. |
| Volume of Distribution | 1.5-2.5 L/kg, indicating extensive tissue distribution. |
| Bioavailability | Oral bioavailability is 50-60% due to first-pass metabolism. |
| Onset of Action | Intravenous: 5-10 minutes; oral: 30-60 minutes. |
| Duration of Action | Clinical effect duration is 4-6 hours after intravenous administration; after oral administration, effect lasts 4-8 hours. |
NEOTRIZINE (sulfamethoxazole/trimethoprim) 800 mg/160 mg orally every 12 hours for 5-14 days, depending on indication.
| Dosage form | TABLET |
| Renal impairment | CrCl 30-50 mL/min: same dose every 12 hours for 5-7 days; CrCl 15-29 mL/min: 50% dose every 12 hours; CrCl <15 mL/min: avoid use (except for Pneumocystis jirovecii pneumonia prophylaxis with dose adjustment). |
| Liver impairment | Child-Pugh Class A: no adjustment; Child-Pugh Class B: consider use with caution, monitor for toxicity; Child-Pugh Class C: avoid use (due to risk of hepatotoxicity). |
| Pediatric use | Children >2 months: 8 mg/kg/day trimethoprim and 40 mg/kg/day sulfamethoxazole divided every 12 hours. Dosing based on trimethoprim component: 4 mg/kg/dose every 12 hours. |
| Geriatric use | Elderly patients: increased risk of renal impairment, hyperkalemia, and adverse effects. Adjust dose based on renal function (CrCl). Avoid if CrCl <15 mL/min. Monitor electrolytes and renal function closely. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for NEOTRIZINE (NEOTRIZINE).
| Breastfeeding | Unknown M/P ratio; present in breast milk. Caution advised due to risk of sedation and impaired feeding in the infant. |
| Teratogenic Risk | First trimester: Increased risk of congenital malformations including neural tube defects and cardiovascular anomalies. Second and third trimesters: Risk of preterm birth, low birth weight, and neonatal adaptation syndrome (hypotonia, feeding difficulties). |
| Fetal Monitoring |
■ FDA Black Box Warning
Neotrizine contains sulfadiazine and should not be used in infants less than 2 months of age due to risk of kernicterus. Sulfonamides have been associated with fatal reactions such as Stevens-Johnson syndrome, toxic epidermal necrolysis, agranulocytosis, aplastic anemia, and other blood dyscrasias.
| Serious Effects |
["Hypersensitivity to sulfonamides","Infants less than 2 months of age (except for congenital toxoplasmosis)","Porphyria","Severe hepatic or renal impairment","Pregnancy at term and during nursing (risk of kernicterus)"]
| Precautions | ["Hypersensitivity reactions including skin rashes and Stevens-Johnson syndrome","Hematologic toxicity: agranulocytosis, aplastic anemia","Hepatic injury: jaundice, hepatitis","Renal toxicity: crystalluria, oliguria","Kernicterus in neonates"] |
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| Monitor fetal growth via ultrasound; assess for signs of teratogenic effects. Monitor maternal blood pressure, liver function, and complete blood count. Neonatal monitoring for withdrawal symptoms post-delivery. |
| Fertility Effects | May cause reversible reduction in sperm count in males; unclear effect on female fertility. Use with caution in patients attempting conception. |