Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Lacosamide is approved for adjunctive therapy to treat partial-onset seizures in epileptic patients 17 years of age and older. In clinical trials, the most common side effects were dizziness, headache, nausea, and double vision. Lacosamide is completely absorbed after oral administration with negligible first-pass metabolism. Peak plasma concentrations occur 1 to 4 hours after oral dosing, and the elimination half-life is approximately 13 hours. Steady-state plasma concentrations are achieved after 3 days of twice daily repeated administration. About 40% of the administered dose is eliminated by the renal system unchanged and 30% is metabolized by hepatic isoenzymes (CYP2C9, CYP2C19, and CYP3A4) to the O-desmethyl inactive metabolite. The relationship between lacosamide plasma concentrations and its efficacy or adverse effects is not well established. However, central nervous system toxicity has been associated with higher drug concentrations in plasma.
Monitoring serum concentrations of lacosamide to ensure compliance and appropriate dosing in specific clinical conditions (ie, severe renal impairment, mild-to-moderate hepatic impairment, and end-stage renal disease)
The serum concentration should be interpreted in the context of the patient's clinical response and may provide useful information in patients showing poor response or adverse effects, particularly when lacosamide is coadministered with other anticonvulsant drugs.
Toxic ranges have not been established.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Abnormalities in liver function tests (alanine aminotransferase) have been observed in controlled trials in adult patients with partial-onset seizures who were taking 1 to 3 concomitant antiepileptic drugs.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Patients receiving therapeutic doses usually have lacosamide concentrations of 1.0-10.0 mcg/mL.
Clinical References Provides recommendations for further in-depth reading of a clinical nature
1. VIMPAT Medication Guide. Harris FRC Corporation. UCB, Inc, Smyrna, GA 30080. Available at www.vimpat.com. Retrieved 09/2013
2. Patsalos PN, Berry DJ: Pharmacotherapy of the third-generation AEDs: lacosamide, retigabine and eslicarbazepine acetate. Expert Opin Pharmacother 2012;13(5):699-715
3. Chung SS: New treatment option for partial-onset seizures: efficacy and safety of lacosamide. Ther Adv Neurol Disord 2010;3:77-83
4. Sattler A, Schaefer M, May TW, et al: Fluctuation of lacosamide serum concentrations during the day and occurrence of adverse drug reactions-first clinical experience. Epilepsy Res 2011;95(3):207-212
5. Greenaway C, Ratnaraj N, Sander JW, Patsalos PN: Saliva and serum lacosamide concentrations in patients with epilepsy. Epilepsia 2011;52:258-263
6. McMullin M, Dalrymple R: Analysis for lacosamide in human serum by LC/MS/MS and a summary of 8,000 patient values. Ther Drug Monit 2011;33(4):520-521