Nursing care
Valproic Acid: what to check before you give it
Written and reviewed by Dana Whitfield, RN, MSN · 4 min read · Updated September 2026
Short answer
Valproic acid nursing care is built around two non-negotiable risks: hepatotoxicity and teratogenicity. Baseline liver enzymes are drawn before the first dose, and a pregnancy test is required before starting therapy in anyone who could conceive, regardless of the indication being treated.
Why this drug and not another
Valproic acid, and its prodrug divalproex, is reached for across a wider range of indications than most anticonvulsants: generalised and absence seizures, bipolar mania, and migraine prophylaxis. That breadth is exactly why it turns up on units where a nurse might not expect an anticonvulsant, including psychiatric and general medical wards.
The trade-off for that versatility is a narrower safety margin on two specific risks. Valproic acid is hepatotoxic and teratogenic, and neither risk is theoretical or rare enough to treat as fine print. Before it starts in anyone who could become pregnant, a pregnancy test is required, and baseline liver enzymes are drawn regardless of indication.
Administration and timing
Give with food to reduce GI upset, which is common and usually mild. Extended-release and delayed-release formulations are not interchangeable with immediate-release, and tablets or capsules are not crushed or chewed, since altering the formulation changes absorption and can push serum levels outside the therapeutic range.
Divalproex sprinkle capsules can be opened and the contents sprinkled on soft food for patients who cannot swallow tablets, but this should be confirmed against the specific product ordered rather than assumed. Doses are typically given on a fixed schedule, and consistency in timing matters more with valproic acid than with drugs that have a wider therapeutic window.
Monitoring parameters
Liver function tests are drawn at baseline, before the first dose, and monitored periodically throughout therapy, particularly in the first six months when hepatotoxicity risk is highest. A pregnancy test is required before starting in anyone of childbearing potential, and this is not optional or indication-dependent; it applies whether the drug is being started for seizures, bipolar disorder, or migraine.
Serum ammonia may be checked if the patient develops altered mental status, since valproic acid can cause hyperammonemic encephalopathy even with normal liver enzymes. Platelet counts and coagulation studies are monitored as well, given the drug's association with thrombocytopenia, and this becomes particularly relevant before any planned surgical procedure.
Adverse effects to report
Report signs of liver injury immediately: jaundice, right upper quadrant pain, unexplained nausea or vomiting, dark urine, or lethargy, especially in the first six months of therapy when hepatotoxicity risk peaks and in children under two, who carry the highest risk of all.
Altered mental status, confusion, or lethargy without a clear cause can indicate hyperammonemic encephalopathy and warrants an ammonia level and provider notification even if liver enzymes look normal. Easy bruising or unusual bleeding suggests thrombocytopenia and should be reported, along with any signs of pancreatitis such as severe abdominal pain, which is rare but serious.
Contraindications and cautions
Valproic acid is contraindicated in known hepatic disease or significant hepatic dysfunction, and in patients with known urea cycle disorders, given the hyperammonemia risk. It is contraindicated for migraine prophylaxis in pregnancy specifically, and used in pregnancy for seizures or bipolar disorder only when no safer alternative controls the condition and the risk has been discussed.
Its teratogenic risk includes neural tube defects and, with chronic in-utero exposure, effects on cognitive development, which is why pregnancy status is established before the first dose rather than after conception is confirmed. Use with caution in patients with a bleeding disorder or those on other hepatotoxic medications, where the combined risk is higher than either drug alone.
Teaching points the exam tests
Expect NCLEX items that pair a female patient of childbearing age with a new valproic acid order and ask what the nurse should verify before administration; the answer is pregnancy status. Expect a second pattern where a patient on valproic acid reports vague symptoms like fatigue or nausea, and the correct action is to check liver function rather than reassure and reassess later.
Teach patients to recognise and report jaundice, unusual bruising, and any confusion or unusual drowsiness without delay. Counsel anyone who could become pregnant on reliable contraception and the need to discuss pregnancy planning with the prescriber before conception, not after. Reinforce that the drug is not stopped abruptly without medical guidance, given the seizure or mood destabilisation risk that can follow.
The next step on this is the same as on everything else here: answer questions and read the rationales. Our neurological practice questions are the closest set to what this page covers.
Common questions
Why is a pregnancy test required before starting valproic acid?
Valproic acid is teratogenic, with a well-established risk of neural tube defects and other developmental effects from in-utero exposure. Pregnancy status is confirmed before the first dose in anyone who could conceive, regardless of why the drug is being started, so the risk is known before, not after, exposure occurs.
What baseline labs are needed before starting valproic acid?
Baseline liver function tests are required before the first dose, since hepatotoxicity is a known and sometimes serious risk with this drug. A pregnancy test is also required in anyone of childbearing potential before therapy begins.
What does hyperammonemic encephalopathy look like with valproic acid?
It presents as altered mental status, confusion, or lethargy, and it can occur even when liver enzymes are within normal limits. A serum ammonia level should be checked and the prescriber notified if these signs appear in a patient on valproic acid.
Is divalproex the same as valproic acid for nursing purposes?
Divalproex is a prodrug that converts to valproic acid in the body, and it carries the same hepatotoxicity and teratogenicity risks, so the same baseline labs and pregnancy testing apply. Formulations differ in release profile, so the specific product ordered should be confirmed before administration.