Which are common severe adverse effects of Valproic acid?

• A. Hyperammonemia
• B. Thrombocytopenia
• C. Hepatotoxicity
• D. Thrombocytopenia and hepatotoxicity

Answer: (D)

Valproic acid has two particularly important and potentially life‑threatening adverse effects: hepatotoxicity and thrombocytopenia. Hepatotoxicity can be severe and even fatal, especially in young children, those with preexisting liver disease, or when used with other hepatotoxic drugs. It may present with fatigue, nausea, vomiting, abdominal pain, jaundice, and markedly elevated liver enzymes, often developing within the first several months of therapy, so baseline and periodic liver function tests are essential and therapy should be stopped if liver injury signs appear.

Thrombocytopenia is another major concern, leading to an increased risk of bleeding due to reduced platelet counts or platelet dysfunction. Regular blood counting is advised, particularly at higher doses or when combined with other drugs that affect clotting. If platelet counts drop or bleeding occurs, dose adjustment or discontinuation is warranted.

Hyperammonemia can occur with valproate, especially in the setting of hepatic dysfunction, but it is not as consistently observed as a severe adverse effect as hepatotoxicity and thrombocytopenia. Therefore, the combination of thrombocytopenia and hepatotoxicity best represents the common severe adverse effects of valproic acid.