What are the common adverse effects of Vimpat (lacosamide)?

Vimpat (Lacosamide) Adverse Effects

The most common adverse effects of Vimpat (lacosamide) are dizziness, headache, nausea, diplopia (double vision), and drowsiness, with the critical safety concern being dose-related PR interval prolongation requiring cardiovascular monitoring. 1

Most Frequent Neurological Side Effects

• Dizziness is the most prominent neurological adverse effect, occurring at 3.53 times the rate of placebo (99% CI 2.20 to 5.68) 2
• Diplopia (double vision) occurs at 5.29 times the placebo rate (99% CI 1.97 to 14.23), representing one of the most statistically significant adverse effects 2
• Abnormal coordination and ataxia show the strongest association with lacosamide, occurring at 6.12 times the placebo rate (99% CI 1.35 to 27.77) 2
• Headache occurs frequently, though the increased risk compared to placebo (RR 1.34,99% CI 0.83 to 2.18) does not reach statistical significance 2
• Somnolence and drowsiness are reported but similarly do not reach statistical significance (RR 1.44,99% CI 0.67 to 3.09) 2

Gastrointestinal Adverse Effects

• Nausea occurs at 2.37 times the placebo rate (99% CI 1.23 to 4.58) 2
• Vomiting is significantly increased at 3.49 times the placebo rate (99% CI 1.43 to 8.54) 2
• Abdominal pain has been documented in clinical trials 1

Cardiovascular Effects - Critical Safety Concern

• Small dose-related increases in PR interval prolongation have been observed and require electrocardiographic monitoring 1, 3
• Complete atrioventricular block with extreme bradycardia requiring pacemaker placement has been reported, particularly when combined with other sodium channel blockers like carbamazepine or eslicarbazepine 4
• Supraventricular tachyarrhythmias, repolarization changes, and rare cases of cardiac arrest or sudden death have been documented 4
• Obtain baseline electrocardiogram before initiating lacosamide and perform regular monitoring during the first weeks of treatment 4
• Contraindicated in patients with history of atrioventricular block, ischemic heart disease, or heart failure 4

Less Common but Serious Adverse Effects

• Skin rashes and hematotoxicity have been reported 5
• Psychological symptoms and suicide risk require monitoring 5
• Memory impairment, weight gain, and excessive laughing (rare) have been documented 6
• Fatigue shows a trend toward increased occurrence (RR 2.11,99% CI 0.92 to 4.85) though not statistically significant 2

Driving and Safety Impairment

• Lacosamide may impair driving ability due to central nervous system effects, particularly during treatment initiation or dose changes 1, 3
• Patients must be explicitly counseled about potential driving impairment; failure to provide this warning represents a critical clinical pitfall that could lead to accidents 1
• The incidence of arousal-related adverse events with lacosamide is lower than carbamazepine, and epidemiological studies show no increased traffic accident risk compared to other antiepileptic drugs 1

Tolerability Profile and Withdrawal Rates

• Treatment withdrawal for any reason occurs at 1.88 times the placebo rate (95% CI 1.40 to 2.52), indicating that adverse effects lead to discontinuation in a meaningful proportion of patients 2
• The majority of adverse events are mild to moderate in severity 7
• Both oral and intravenous formulations demonstrate equivalent tolerability profiles 7
• Intravenous administration adds local adverse events including injection site discomfort, pain, irritation, and erythema 7

Critical Clinical Pitfall to Avoid

• Abrupt discontinuation of lacosamide may precipitate withdrawal seizures, which poses greater risk than continuing the medication even in special populations 1, 8
• When combining lacosamide with other sodium channel blockers (carbamazepine, eslicarbazepine, oxcarbazepine), exercise extreme caution due to additive cardiac conduction effects 4