VALMID
Clinical safety rating: caution
Comprehensive clinical and safety monograph for VALMID (VALMID).
Valproate increases gamma-aminobutyric acid (GABA) concentrations in the brain either by inhibiting GABA transaminase or by increasing glutamic acid decarboxylase activity, thereby enhancing inhibitory neurotransmission.
| Metabolism | Extensively metabolized in the liver primarily via glucuronidation (approx. 50%) and beta-oxidation (approx. 40%), with minor contributions from CYP2C9, CYP2A6, and CYP2B6 isoenzymes. |
| Excretion | Renal excretion accounts for >90% of elimination, primarily as unchanged drug via glomerular filtration and tubular secretion. Biliary/fecal excretion is minimal (<5%). |
| Half-life | Terminal elimination half-life is 2-4 hours in adults with normal renal function; prolonged to 10-20 hours in severe renal impairment (CrCl <30 mL/min), necessitating dose adjustment. |
| Protein binding | Approximately 92% bound to albumin; minimal binding to alpha-1-acid glycoprotein. |
| Volume of Distribution | Vd = 0.5-0.8 L/kg, indicating distribution primarily into extracellular fluid; higher Vd in obesity. |
| Bioavailability | Oral bioavailability is 85-95% due to extensive absorption; food decreases rate but not extent of absorption. Intravenous bioavailability is 100%. |
| Onset of Action | Oral: 30-60 minutes; Intravenous: 5-15 minutes. |
| Duration of Action | 4-6 hours for oral; 3-5 hours for intravenous. Duration is dose-dependent; at higher doses, effects may persist up to 8 hours. |
250 mg orally three times daily.
| Dosage form | CAPSULE |
| Renal impairment | CrCl 50–80 mL/min: no adjustment; CrCl 30–49 mL/min: 250 mg twice daily; CrCl 15–29 mL/min: 250 mg once daily; CrCl <15 mL/min or hemodialysis: 250 mg every other day. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: contraindicated. |
| Pediatric use | 20 mg/kg/day orally divided every 8 hours; maximum 750 mg/day. |
| Geriatric use | Initiate at 125 mg twice daily; titrate cautiously based on renal function. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for VALMID (VALMID).
| Breastfeeding | Excretion into breast milk unknown; risk of infant sedation or withdrawal due to long half-life. M/P ratio not established. Avoid breastfeeding or use with caution. |
| Teratogenic Risk | Valmid (ethinamate) is a sedative-hypnotic with limited data in pregnancy. First trimester: potential for teratogenicity based on animal studies; avoid. Second/third trimester: may cause neonatal withdrawal or sedation; use only if clearly needed. |
| Fetal Monitoring |
■ FDA Black Box Warning
Hepatotoxicity, including fatal hepatic failure, especially in children under 2 years of age and those with congenital metabolic disorders, severe seizure disorders, or organic brain disease. Fatal pancreatitis has occurred in children and adults. Valproate is contraindicated in patients with known mitochondrial disorders caused by POLG mutations.
| Common Effects | Application site reactions burning irritation itching and redness |
| Serious Effects |
Hypersensitivity to valproate; active liver disease or significant hepatic dysfunction; known mitochondrial disorder caused by POLG mutations; urea cycle disorders.
| Precautions | Hepatotoxicity risk is highest in children under 2; pancreatitis can occur at any time; teratogenicity including neural tube defects; thrombocytopenia; hyperammonemia; hypothermia; multi-organ hypersensitivity reactions; monitoring of liver function, platelet counts, and ammonia levels recommended. |
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| Monitor maternal sedation, respiratory depression, and neonatal withdrawal signs (irritability, tremors) if used near term. |
| Fertility Effects | Animal studies suggest possible impairment of fertility at high doses; human data insufficient. |