PlainMeds provides educational information only. This is not medical advice. Always consult your doctor or pharmacist.

lamotrigine vs valproate

Side-by-side comparison of lamotrigine and valproate. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.

minor Known Drug Interaction

Valproate ↑ lamotrigine ? valproate Increased lamotrigine concentrations slightly more than 2-fold. There are conflicting study results regarding effect of lamotrigine on valproate concentrations: 1) a mean 25% decrease in valproate concentrations in healthy volunteers, 2) no change in valproate concentrations in controlled clinical trials in patients with epilepsy.

Recommendation: Your doctor will likely need to lower your lamotrigine dose to avoid side effects.

Drug Class
lamotrigine Anticonvulsant
valproate Anticonvulsant / Mood Stabilizer
Type
lamotrigine Prescription
valproate Prescription
Summary
lamotrigine

Lamotrigine is a medicine that can treat seizures and bipolar disorder. It works by reducing irregular electrical activity in the brain.

valproate

Valproate sodium injection is used when you cannot take valproate pills. It helps control seizures.

What It Treats
lamotrigine

Lamotrigine can treat epilepsy in adults and children 2 years and older. It can help with partial-onset seizures, primary generalized tonic-clonic seizures, and generalized seizures of Lennox-Gastaut syndrome. It can also be used to delay mood episodes in adults with bipolar I disorder.

valproate

This medicine treats certain types of seizures. It can be used alone or with other medicines to treat complex partial seizures. It also treats simple and complex absence seizures, and multiple seizure types that include absence seizures.

How It Works
lamotrigine

Lamotrigine affects how nerves in the brain send signals to each other. It is thought to work by decreasing the release of certain chemicals. This helps to stabilize electrical activity and prevent seizures or mood swings.

valproate

Valproate affects the levels of certain chemicals in your brain. These chemicals help to control seizures. This medicine helps to reduce the frequency of seizures.

Common Side Effects
lamotrigine
  • Dizziness
  • Headache
  • Double vision
  • Uncoordinated movements
  • Nausea
valproate
  • Headache
  • Dizziness
  • Nausea
  • Pain at the injection site
FAERS Reports
lamotrigine
  • Skin rash 8,408
  • Seizure 6,527
  • Feeling sick to your stomach 6,151
  • Tiredness 5,914
  • Feeling lightheaded 5,771
valproate
  • The medicine is interacting with another medicine 1,187
  • The baby was exposed to the medicine during pregnancy 1,043
  • Sleepiness 951
  • Seizures 813
  • Harmful effects from different substances 757
Serious Warnings
lamotrigine

Lamotrigine can cause a serious skin rash that may require you to go to the hospital. This rash can be life-threatening. The risk is higher in children. Stop taking lamotrigine and see a doctor right away if you get a rash, fever, or swollen lymph nodes.

valproate

Valproate can cause life-threatening liver problems, especially in the first 6 months of treatment. Children under 2 and people with mitochondrial disorders have a higher risk. Valproate can also harm an unborn baby, causing birth defects and lower IQ. It can also cause pancreatitis, which can be fatal.

Pregnancy
lamotrigine

Tell your doctor if you are pregnant or plan to become pregnant. Lamotrigine may cause harm to an unborn baby. There is a pregnancy registry for women who take lamotrigine during pregnancy. You can enroll by calling 1-888-233-2334.

valproate

Valproate can cause serious birth defects if taken during pregnancy. Do not take this medicine if you are pregnant or plan to become pregnant unless other medicines don't work for you. There is a pregnancy registry for women who take valproate during pregnancy; call 1-888-233-2334 to enroll.

Also Compare, Nearby Drugs

How to Read This lamotrigine vs valproate Comparison

lamotrigine is classified in the Anticonvulsant drug class, while valproate sits within the Anticonvulsant / Mood Stabilizer class. Drugs from different classes work through distinct mechanisms, so a head-to-head comparison illustrates trade-offs rather than equivalence. Both drugs are prescription-only, so a licensed provider must authorize use.

Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, lamotrigine has 32,771 submissions while valproate has 4,751. Those figures reflect cumulative reporting volume, not per-patient risk, so older, widely dispensed drugs typically look worse on count alone. These two drugs have a known minor interaction flagged in FDA labeling, attributed to valproate slows down the process your body uses to get rid of lamotrigine, which causes the amount of lamotrigine in your blood to more than double.. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.

A table cannot substitute for clinical judgment. Effectiveness, tolerability, drug-drug interactions with your other medications, kidney and liver function, pregnancy status, insurance formulary, and price all feed into a decision that only a licensed prescriber can make responsibly. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This page is for educational purposes only, is not medical advice, and should not be used to self-switch between lamotrigine and valproate - always consult your physician or pharmacist first.

Important: This comparison is for informational purposes only. Drug effects vary between individuals. Always consult your doctor or pharmacist for personalized medical advice.