Testing valproic acid levels is essential in treating bipolar disorder to ensure the medication is at a therapeutic range.

Valproic acid is a medication used to treat various medical conditions, including epilepsy, migraine, and bipolar disorder.

In bipolar disorder, valproic acid plays an important role in stabilizing mood and reducing the frequency and severity of manic and depressive episodes.

Evidence suggests that valproic acid (VPA) may work for bipolar disorder by affecting various brain functions:

  • Stabilizing brain activity: VPA may calm brain cells by blocking certain channels that allow sodium ions to enter. This helps prevent abnormal electrical signals that can lead to mood episodes.
  • Boosting calming neurotransmitters: VPA boosts a neurotransmitter called GABA, which helps produce a calming effect. Normally, there are enzymes that break down GABA, but VPA stops them from working. This means there’s more GABA to soothe an overactive brain, which is common in bipolar disorder.
  • Creating more GABA: VPA may stimulate the production of GABA by converting the brain’s primary excitatory neurotransmitter, glutamate, into GABA.
  • Influencing genes: VPA affects how certain genes work by blocking enzymes called HDACs (histone deacetylases). This can impact genes related to mood, thinking, and protecting brain cells.
  • Adjusting calcium channels: VPA may affect various calcium channels in neurons, which play roles in neurotransmission, neuroprotection, and more.

Overall, VPA’s actions aim to stabilize mood episodes, reduce overexcitability in the brain, and promote more balanced neurotransmitter activity, making it helpful in managing bipolar disorder.

Factors such as your metabolism, age, weight, and overall health can influence how your body processes and absorbs valproic acid. As a result, two people taking the same dosage of valproic acid may have different levels in their bodies.

Testing VPA levels shows:

  • Therapeutic monitoring: Observing valproic acid levels helps healthcare professionals ensure the drug is within the therapeutic range, which means it’s at a concentration that effectively treats bipolar disorder.
  • Dosage adjustment: If valproic acid levels are too low, it may suggest that the current dosage isn’t sufficient to manage your condition.
  • Avoiding toxicity: If valproic acid levels are too high, it can lead to toxicity and potentially harmful side effects.

For bipolar disorder, the target level of valproic acid in the blood is generally within the range of 50–125 micrograms per milliliter (mcg/mL). This range helps to stabilize mood and manage manic episodes effectively.

In particular, a 2022 study found that maintaining serum VPA levels between 50–74 mcg/mL may be more effective in preventing acute mood episodes during maintenance therapy in people with bipolar disorder compared with lower levels (less than 50 mcg/mL).

What is the target valproic acid level for mania?

For mania associated with bipolar disorder, the target valproic acid levels are typically 50–125 mcg/mL. It usually takes around 14 days to reach this level.

The initial dosage for the treatment of mania typically ranges from 250–500 milligrams (mg), taken three times a day. Adjustments are made as needed to achieve the desired clinical effect.

If you’re using the extended-release form, you’ll usually begin with a lower dose of 25 mg per kilogram (mg/kg) once a day. If needed, the dose can be increased to a maximum of 60 mg/kg per day to get the desired effect.

All medications come with potential side effects, which you may or may not experience.

Some potential side effects of valproic acid for bipolar disorder may include:

  • gastrointestinal symptoms like nausea, vomiting, diarrhea, and abdominal pain
  • drowsiness
  • shakiness or tremors
  • hair loss
  • blood disorders, such as a decrease in platelets or white blood cells
  • an increase in ammonia levels in the blood (hyperammonemia)
  • changes in mood, behavior, or cognitive function
  • birth defects if taken during pregnancy
  • metabolic effects such as increased appetite and potential weight gain
  • liver damage
  • pancreatitis (this is rare)

Some research suggests that VPA use in females is associated with an increased risk of hormone abnormalities, polycystic ovarian syndrome (PCOS), and obesity. You may want to discuss the pros and cons with your doctor if you’re concerned about these side effects.

If you develop hyperammonemia, you may also experience confusion or lethargy. Also, doctors will typically monitor your liver enzymes while on this drug to prevent liver damage.

Valproic acid (VPA) is a medication designed to help manage mood stability in people with bipolar disorder. To make sure it’s effective without causing harm, it’s important to maintain specific VPA levels.

If your levels are too low, it will not effectively manage your bipolar disorder symptoms. If levels are too high, it can lead to unwanted side effects or even toxicity. This is why regular monitoring and adjustments are essential for achieving the best results.

Follow your healthcare team’s guidance and get routine blood tests to keep your valproic acid levels within the optimal range.