RUFINAMIDE
Clinical safety rating
cautionComprehensive clinical and safety monograph for RUFINAMIDE (RUFINAMIDE).
Modulates sodium channels, prolonging the inactive state, thereby stabilizing neuronal membranes and inhibiting repetitive firing. Also enhances the activity of gamma-aminobutyric acid (GABA) at GABA-A receptors.
| Metabolism | Primarily hydrolyzed by carboxylesterases (CES1 and CES2) to inactive metabolite. Minor CYP450 metabolism (CYP2C19, CYP3A4, CYP1A2). |
| Excretion | Renal: 85% as unchanged drug; fecal: 15% as unchanged drug and metabolites. |
| Half-life | Terminal elimination half-life is 6–10 hours in adults, requiring twice-daily dosing for stable trough concentrations. |
| Protein binding | 34% bound to albumin; low binding reduces displacement interactions. |
| Volume of Distribution | 0.5–0.8 L/kg, indicating distribution into total body water without extensive tissue accumulation. |
| Bioavailability | Oral: ~85% (highly bioavailable); food delays absorption but does not reduce extent. |
| Onset of Action | Oral: Clinical effect observed within 1–2 weeks at steady state; no immediate effect. |
| Duration of Action | Duration of action is approximately 12 hours, consistent with twice-daily dosing; trough levels maintained with regular administration. |
| Molecular Weight | 238.2 |
Adults: 200-400 mg orally twice daily, with titration from 200 mg twice daily increasing by 200 mg/day every 2 weeks to a maximum of 3200 mg/day divided twice daily.
| Dosage form | SUSPENSION |
| Renal impairment | No specific dose adjustment guidelines; use with caution in severe renal impairment (CrCl <30 mL/min). |
| Liver impairment | Child-Pugh A: No adjustment. Child-Pugh B: Reduce dose by 25%. Child-Pugh C: Reduce dose by 50%. |
| Pediatric use | Children ≥4 years: 10 mg/kg/day orally divided twice daily, titrating by 10 mg/kg/day every 2 weeks to a maximum of 45 mg/kg/day or 3200 mg/day, whichever is less. |
| Geriatric use | No specific dose adjustment, but start at lower end of dosing range due to potential reduced clearance and increased sensitivity. |
| 1st trimester | Rufinamide is pregnancy category C. Limited human data; animal studies have shown developmental toxicity. Use only if benefit outweighs risk. Consider folate supplementation and monitor for neural tube defects. |
| 2nd trimester | Continue risk-benefit assessment. No specific trimester-specific data; potential for continued fetal exposure. Monitor fetal growth and development. |
| 3rd trimester | Neonatal withdrawal or sedation possible. Observe neonate for symptoms. Drug may interfere with vitamin K metabolism; consider vitamin K supplementation in mother before delivery. |
Clinical note
Comprehensive clinical and safety monograph for RUFINAMIDE (RUFINAMIDE).
| Placental transfer | Rufinamide crosses the placenta (animal studies indicate transfer; human data limited but expected due to low molecular weight). |
| Breastfeeding | Limited data; rufinamide is excreted into breast milk in low amounts. Relative infant dose estimated to be 2-3% of maternal weight-adjusted dose. Monitor infant for sedation, poor feeding, or weight loss. Use with caution. |
| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | Rufinamide is a triazole derivative antiepileptic drug. Data from animal studies indicate developmental toxicity including embryofetal mortality, growth retardation, and structural anomalies at clinically relevant exposures. In humans, there are no adequate well-controlled studies; however, based on animal data and mechanism of action, rufinamide is classified as Pregnancy Category C. Use during pregnancy only if potential benefit justifies potential risk to fetus. First trimester exposure is associated with increased risk of major congenital malformations, particularly neural tube defects and orofacial clefts. Late pregnancy exposure may cause neonatal hemorrhage due to vitamin K deficiency and persistent pulmonary hypertension. Third trimester use may lead to withdrawal symptoms in neonates. |
| Fetal Monitoring | Monitor maternal serum rufinamide levels every trimester and postpartum to adjust dose for pharmacokinetic changes. Perform fetal ultrasound at 18-20 weeks to assess for structural anomalies. Obtain vitamin K levels in mother in third trimester and administer oral vitamin K 10 mg/day from 36 weeks to prevent neonatal hemorrhage. Monitor neonates for signs of withdrawal (e.g., irritability, feeding difficulties) and coagulation status post-delivery. |
| Fertility Effects | In animal studies, rufinamide had no adverse effects on male or female fertility at doses up to 60 mg/kg/day (approximately 3 times maximum recommended human dose on mg/m² basis). Human data are insufficient to assess fertility effects. Establish pregnancy risk prior to initiating therapy in women of childbearing potential. |
■ FDA Black Box Warning
None
| Serious Effects |
Known hypersensitivity to rufinamide or any excipientsFamilial short QT syndrome
| Precautions | Suicidal behavior and ideation, Withdrawal-precipitated seizures if discontinued abruptly, Status epilepticus, Dizziness, somnolence, and ataxia, QT interval shortening (clinical significance unknown), Multiorgan hypersensitivity reactions, Hematologic abnormalities (e.g., leukopenia, eosinophilia) |
| Food/Dietary | Avoid grapefruit and grapefruit juice as they may inhibit CYP2E1 and increase rufinamide levels. Rufinamide should be taken with food to improve absorption. No other specific dietary restrictions are known, but maintenance of consistent meal patterns is advised. |
| Clinical Pearls | Rufinamide is a triazole derivative used as adjunctive therapy for seizures associated with Lennox-Gastaut syndrome. It prolongs the inactive state of voltage-gated sodium channels. Dose titration is essential to minimize adverse effects; start at 10 mg/kg/day divided twice daily and increase by 10 mg/kg/day every other day up to 45 mg/kg/day (max 3200 mg/day). Monitor for QT interval prolongation; avoid use with drugs that shorten QT. Rufinamide can decrease the efficacy of oral contraceptives; advise alternative contraception. It may cause dizziness, somnolence, and coordination abnormalities; caution patients about driving. Stevens-Johnson syndrome has been reported; discontinue if rash develops. |
| Patient Advice | Take rufinamide exactly as prescribed; do not stop suddenly as this may increase seizure frequency. · Do not change dose without consulting your doctor; dose adjustments should be gradual. · Avoid grapefruit and grapefruit juice as they may affect the drug's metabolism. · Rufinamide may interact with oral contraceptives; use additional non-hormonal birth control. · Common side effects include headache, dizziness, fatigue, and nausea; report any skin rash or signs of allergic reaction immediately. · Avoid driving or operating heavy machinery until you know how rufinamide affects you. · Store tablets at room temperature away from moisture and heat. |
Loading safety data…