Valproic Acid

Valproic Acid

Alternate Test Name

Depakote
Depakene
Valproic Acid

VPA

Epic Mnemonic
Sunquest Mnemonic

LAB24
VALP

Category

Chemistry

Methodology

Enzyme immunoassay

Test Performance Schedule

Sunday - Saturday

Result Availability

Within 24 hours – STAT upon request

Container

Preferred: Gold top (SST) tube, Red top (serum) tube, Green top (lithium heparin) tube or Mint top (PST) tube
Alt: Lavender top (EDTA) tube

Volume

Pref. Vol.: 1.0 mL serum or plasma
Min. Vol.: 0.5 mL serum or plasma

Collection Instructions

• Collection Timing: Specimens for valproic acid analysis should be drawn just prior to dose, preferably in the fasting state.

• Routine venipuncture

• Immediately after collection, gently invert tube 5-10 times

• Clot 30 minutes

• Promptly centrifuge 10 minutes

• If no gel barrier is present immediately transfer serum or plasma to a plastic tube and refrigerate

• Properly centrifuged gel barrier tube does not require transfer of serum or plasma to separate tube

Transportation Instructions

Refrigerated

Stability

• Room Temperature: 2 days
• Refrigerated: 5 days

Causes for Rejection

Remarks

CPT Codes

80164

Effective/Revised

03/29/2017

Valproic acid (Depakene) is a relatively new anticonvulsant medication which is used chiefly for the treatment of primary and secondary generalized seizures, but is also effective against absence seizures. It is particularly effective in myoclonus, and is the drug of choice in photosensitive epilepsy.Although VPA is used in conjunction with other anti-epileptic medications, more recent studies have shown benefits of converting treatment to monotherapy with VPA. Also, a growing body of evidence suggests that VPA is useful in treatment of affective disorders; in particular, lithium-insensitive bipolar disorders.

VPA has the fewest adverse effects of all the widely-used anti-epileptic agents. The most common side effects are gastrointestinal disturbances such as nausea and vomiting. Some incidences of tremor, coma or stupor have been noted; these often occur in conjunction with co-administration of other

anti-epileptic drugs. Rare occurrences of hepatic failure, Reye-like syndrome, pancreatitis or thrombocytopenia are thought to be individualized reactions unrelated to drug levels.

Pharmacokinetics of VPA are highly variable, depending on the form of the drug and route of administration, as well as individual variations in volume of distribution, metabolism and clearance. Moreover, co-administration of other anti-epileptic drugs can significantly affect VPA metabolism. Therefore, monitoring VPA concentrations during therapy is essential in order to provide the physician with an indicator for adjusting dosage.