MECHANISM OF ACTION
Valproate decreases the clearance of rufinamide.(1,2)
DISCUSSION
Valproate increases rufinamide by 16% to 70%. The largest
effects were seen in children at high doses/concentration of valproate.(2)
The largest increases were seen in patients weighing less than 30 kg.(1)
CLINICAL EFFECTS
Concurrent use of valproate may result in elevated levels
of and toxicity from rufinamide.(1,2)
SEVERITY LEVEL
3-Moderate Interaction: Assess the risk to the patient and
take action as needed.
PATIENT MANAGEMENT
The UK manufacturer of rufinamide recommends that in
patients weighing less than 30 kg who are receiving valproate receive an
initial dose of 200 mg rufinamide daily. The dose may be increased by 200
mg daily after a minimum of 2 days to a maximum dose of 400 mg daily based
on clinical response and tolerability.(1)
PREDISPOSING FACTORS
Greater increases in rufinamide concentrations have
been observed in patients body weights less than 30 kg(1) and with higher
dosages of valproate.(2)
REFERENCES