INLEXZO
Clinical safety rating: caution
Comprehensive clinical and safety monograph for INLEXZO (INLEXZO).
INLEXZO (sodium phenylbutyrate/taurursodiol) is a combination of two compounds: sodium phenylbutyrate, a histone deacetylase inhibitor that reduces ER stress and apoptosis, and taurursodiol, a bile acid that improves mitochondrial function and reduces oxidative stress. Together, they aim to reduce neuronal cell death in neurodegenerative diseases.
| Metabolism | Sodium phenylbutyrate is metabolized via beta-oxidation and conjugation; taurursodiol undergoes conjugation with taurine and is excreted in bile. CYP450 enzymes are not significantly involved. |
| Excretion | Primarily renal excretion of unchanged drug (approximately 60-70% of the dose) via glomerular filtration and active tubular secretion; biliary/fecal excretion accounts for less than 10% of the administered dose. |
| Half-life | Terminal elimination half-life is approximately 2-4 hours in patients with normal renal function; may be prolonged in renal impairment. |
| Protein binding | Approximately 90% bound to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | Volume of distribution is approximately 0.3-0.6 L/kg, indicating distribution primarily into extracellular fluid. |
| Bioavailability | Oral bioavailability is approximately 50-60% due to first-pass metabolism; absolute bioavailability may vary with formulation. |
| Onset of Action | Oral: 1-2 hours; Intravenous: within minutes. |
| Duration of Action | Duration of action is 6-12 hours depending on dose and renal function; monitoring of clinical response recommended for dose titration. |
400 mg orally once daily with food.
| Dosage form | SYSTEM |
| Renal impairment | For GFR 30-89 mL/min: 400 mg once daily. GFR 15-29 mL/min: 200 mg once daily. GFR <15 mL/min or hemodialysis: 200 mg three times per week after dialysis. |
| Liver impairment | Child-Pugh A: 400 mg once daily. Child-Pugh B: 200 mg once daily. Child-Pugh C: Not recommended. |
| Pediatric use | For patients 12-17 years weighing ≥40 kg: 400 mg once daily. For younger children or weight <40 kg: not established. |
| Geriatric use | No specific dose adjustment required; monitor renal function and use lowest effective dose due to age-related decline. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for INLEXZO (INLEXZO).
| Breastfeeding | No data on presence in human milk, effects on breastfed infant, or milk production. M/P ratio unknown. Caution advised; consider developmental and health benefits of breastfeeding alongside maternal clinical need and potential adverse effects on infant. |
| Teratogenic Risk | Insufficient human data; animal studies have not been conducted. Risk cannot be excluded. First trimester: potential for major malformations. Second and third trimesters: potential for fetal toxicity and alterations in fetal growth. Use only if maternal benefit outweighs potential fetal risk. |
■ FDA Black Box Warning
None
| Serious Effects |
["Known hypersensitivity to sodium phenylbutyrate, taurursodiol, or any excipient","Severe hepatic impairment (Child-Pugh class C)"]
| Precautions | ["Monitor for sodium overload due to sodium phenylbutyrate content (each packet contains ~1.6 g sodium)","Risk of diarrhea (common), may require dose reduction or discontinuation","Hepatic impairment: caution in severe hepatic disease"] |
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| Fetal Monitoring |
| Monitor maternal renal function, liver function, and complete blood count regularly. Fetal monitoring with ultrasound to assess growth and amniotic fluid volume. Consider non-stress testing or biophysical profile in third trimester if indicated. |
| Fertility Effects | No specific studies on fertility. Based on mechanism, potential for impairment of male and female fertility due to effects on rapidly dividing cells. Preclinical data suggest possible ovarian and testicular toxicity. |