What over-the-counter (OTC) supplements have potential antiseizure effects?

OTC Supplements with Antiseizure Effects

Direct Answer

There is no high-quality evidence supporting the use of any over-the-counter supplements for antiseizure effects in clinical practice. While anecdotal accounts suggest some herbal substances may have anticonvulsant properties, randomized double-blind controlled trials are lacking 1.

Evidence Assessment

Lack of Proven Efficacy

• No OTC supplements have undergone rigorous randomized controlled trials demonstrating anticonvulsant efficacy 1
• Anecdotal reports exist but lack the scientific rigor required for clinical recommendations 1
• Standard antiepileptic drugs (AEDs) remain the mainstay of symptomatic epilepsy treatment, with approximately 30 FDA-approved medications available 2

Critical Safety Concerns with OTC Supplements

Many herbal remedies and dietary supplements may actually worsen seizure control rather than improve it:

• Multiple herbal substances and dietary supplements can predispose individuals to seizures or worsen existing seizure control 1
• People with epilepsy frequently use OTC products without informing their physicians—only 44% consistently report AED use to other medical professionals 3
• Drug-drug interactions between supplements and AEDs can lead to reduced seizure control and increased adverse drug reactions 3

Specific Supplement Considerations

Calcium and Vitamin D (for hypocalcemia-related seizures only):

• Daily calcium and vitamin D supplementation are recommended for adults with 22q11.2 deletion syndrome to prevent hypocalcemic seizures 4
• Hypocalcemic seizures generally resolve with appropriate supplementation and monitoring alone 4
• This is a specific medical condition requiring supplementation, not a general antiseizure effect 4

St. John's Wort (contraindicated):

• Strong inducer of CYP3A4 enzyme system, which can significantly reduce levels of many AEDs 4
• May decrease platelet aggregation and increase risk of serotonin syndrome when combined with other serotonergic agents 4
• Should be held for 2 weeks before surgery due to multiple drug interactions 4

Clinical Pitfalls

Common Mistakes to Avoid

• Never assume patients are disclosing supplement use—67% of patients with epilepsy know DDIs can cause adverse reactions, but only 56% understand the risk of reduced seizure control 3
• Actively inquire about all OTC products during every clinical encounter, as patients may not volunteer this information 3, 1
• Be aware that 48% of people with epilepsy take dietary supplements that may interact with their AEDs 3

High-Risk Supplement Categories

• Supplements that lower seizure threshold should be avoided entirely in patients with epilepsy 1
• Products containing stimulants or those affecting neurotransmitter systems pose particular risk 1
• Enzyme-inducing or enzyme-inhibiting supplements can alter AED levels unpredictably 3

Evidence-Based Recommendations

For seizure management, prescribe FDA-approved antiseizure medications rather than OTC supplements:

• Newer AEDs including lamotrigine, oxcarbazepine, levetiracetam, topiramate, zonisamide, and lacosamide have demonstrated efficacy equal to older agents with better tolerability profiles 5
• Approximately 30 antiseizure medications are currently available with proven efficacy 2, 5
• Rational AED selection should be based on seizure type, epilepsy syndrome, pharmacokinetics, side effects, and cost—not unproven supplements 6