What is the recommended dosing of brivaracetam for adults, adolescents, and children, including adjustments for rifampin co‑therapy and intravenous administration?

Brivaracetam Dosing

For adults and adolescents ≥16 years, initiate brivaracetam at 50 mg twice daily (100 mg/day total), which can be adjusted based on clinical response to 25-100 mg twice daily (50-200 mg/day total), with no titration required. 1

Adult and Adolescent Dosing (≥16 years)

• Starting dose: 50 mg twice daily (100 mg/day)
• Dose range: 25-100 mg twice daily (50-200 mg/day maximum)
• Key advantage: No titration required—start at target dose 1
• Route flexibility: Oral and IV formulations are bioequivalent with 1:1 conversion 1

Pediatric Dosing (1 month to <16 years)

Use weight-based dosing at 2.0 mg/kg twice daily, with a maximum of 100 mg twice daily for patients >50 kg. 2

This weight-based regimen achieves plasma concentrations in pediatric patients similar to effective adult exposures:

• Patients weighing 11 kg: estimated clearance 1.09 L/h
• Patients weighing 20 kg: estimated clearance 1.81 L/h
• Patients weighing 50 kg: estimated clearance 3.11 L/h
• Adult patients (70 kg): estimated clearance 3.58 L/h 1

Rifampin Co-therapy Adjustment

When co-administered with rifampin, increase the brivaracetam dose by approximately 100% (double the dose) to compensate for the 45% reduction in plasma concentrations caused by CYP2C19 induction. 1

• Rifampin induces CYP2C19, significantly lowering brivaracetam levels
• Dose adjustment should be considered when starting or stopping rifampin 3
• Similar caution applies to St. John's wort (another strong enzyme inducer) 3

Intravenous Administration

IV brivaracetam can be administered as either a 15-minute infusion or as a bolus injection (≤2 minutes), with both methods demonstrating equivalent safety and pharmacokinetics. 4

• IV-to-oral conversion: 1:1 ratio (no dose adjustment needed) 1
• Maximum daily dose: Same as oral (200 mg/day for adults; up to 5 mg/kg/day for pediatrics, not exceeding 200 mg/day) 4
• Both administration methods (15-min infusion vs. bolus) achieved similar plasma concentrations in pediatric patients 4

Special Population Adjustments

Hepatic Impairment

Reduce the starting dose by 50% in all stages of hepatic impairment (Child-Pugh A, B, or C), with a maximum dose of 75 mg twice daily. 1

• Hepatic cirrhosis increases brivaracetam exposure by 50-59% across all Child-Pugh grades 1

Renal Impairment

• No dose adjustment required for renal impairment 1
• Brivaracetam AUC increases only 21% in severe renal impairment
• Inactive metabolites accumulate but are not clinically significant 1

Elderly Patients (≥65 years)

• No dose adjustment required 1
• Plasma clearance slightly lower (0.76 mL/min/kg) compared to young adults (0.83 mL/min/kg) 1

Drug Interaction Considerations

No dose adjustment needed for concomitant enzyme-inducing antiepileptic drugs (carbamazepine, phenytoin, phenobarbital), despite moderate reductions in brivaracetam plasma concentrations. 1, 3

• Carbamazepine: 26% decrease in brivaracetam levels (no adjustment needed) 1
• Phenytoin: 21% decrease in brivaracetam levels (no adjustment needed) 1
• Phenobarbital: 19% decrease in brivaracetam levels (no adjustment needed) 1

Important caveat: Brivaracetam increases carbamazepine-epoxide (active metabolite) by up to 198% at 100 mg twice daily due to epoxide hydrolase inhibition—monitor for carbamazepine toxicity 1

Discontinuation Protocol

Taper brivaracetam over 1-4 weeks depending on dose:

• 25 mg twice daily: 1-week taper
• 50 mg twice daily: 2-week taper
• 100 mg twice daily: 4-week taper 1