Surreal illustration of a young person with symbolic lungs representing valproic acid and eosinophilic pleural effusion.

Valproic Acid and Bipolar Disorder: What You Need to Know About Eosinophilic Pleural Effusion

Kai Mendoza in Health & Wellness December 2025 • 4 min read.

"A rare but serious side effect: Understanding the link between valproic acid, bipolar disorder, and eosinophilic pleural effusion in adolescents."

Valproic acid (VPA) is a common medication prescribed to manage bipolar disorder, especially in young patients. Known for its mood-stabilizing properties, VPA helps to balance the extreme highs and lows associated with this condition. While generally considered safe, it's important to be aware of potential side effects.

One rare but serious adverse reaction is eosinophilic pleural effusion (EPE). EPE occurs when there is an abnormal buildup of fluid in the space between the lungs and the chest wall, characterized by a high concentration of eosinophils, a type of white blood cell. While various factors can cause EPE, certain medications, including VPA, have been linked to its development.

This article explores the connection between VPA and EPE, drawing from a case study of a 15-year-old girl who developed EPE while being treated for bipolar disorder. We'll delve into the symptoms, diagnosis, and management of this condition, providing valuable information for parents, caregivers, and anyone taking or considering VPA.

What is Eosinophilic Pleural Effusion (EPE)?

Surreal illustration of a young person with symbolic lungs representing valproic acid and eosinophilic pleural effusion.

Eosinophilic pleural effusion (EPE) is characterized by an excessive accumulation of fluid in the pleural space, the area between the lungs and the chest wall, with a high concentration of eosinophils, a type of white blood cell that usually fights parasites and plays a role in allergic reactions. Normally, the pleural space contains a small amount of fluid that lubricates the surfaces of the lungs and chest wall, allowing for smooth breathing. In EPE, this fluid increases and becomes filled with eosinophils, leading to various respiratory symptoms.

While the exact mechanisms aren't fully understood, several factors can cause EPE, including infections, autoimmune diseases, and exposure to certain drugs. When EPE is drug-induced, it means the condition developed as a result of taking a particular medication. This is what occurred in the case of the 15-year-old girl being treated with valproic acid for bipolar disorder.

Symptoms of EPE can vary but often include:

Shortness of breath
Chest pain, especially when breathing
Cough
Fever

It's important to note that these symptoms can also be associated with other conditions, making diagnosis challenging. If you or someone you know experiences these symptoms while taking VPA, it's crucial to seek immediate medical attention.

The Takeaway: Staying Informed and Proactive

While eosinophilic pleural effusion is a rare side effect of valproic acid, this case highlights the importance of being aware of potential risks associated with medications, especially in young people. Open communication with your healthcare provider, prompt recognition of symptoms, and immediate medical attention are key to managing such situations effectively. Remember, your health and well-being are the top priorities, and staying informed empowers you to make the best decisions for your care.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1111/appy.12276, Alternate LINK

Title: Valproic Acid-Induced Eosinophilic Pleural Effusion In A Patient With Pediatric Bipolar Disorder

Subject: Psychiatry and Mental health

Journal: Asia-Pacific Psychiatry

Publisher: Wiley

Authors: Armagan Aral, Mirac Baris Usta, Koray Karabekiroglu

Published: 2017-08-30

Everything You Need To Know

What is the role of Valproic Acid in treating pediatric bipolar disorder?

Valproic Acid (VPA) is a common medication prescribed to manage bipolar disorder, particularly in young patients. It is known for its mood-stabilizing properties, helping to balance the extreme highs (mania) and lows (depression) associated with bipolar disorder. It works by affecting certain chemicals in the brain that contribute to mood regulation, thus alleviating the symptoms of the condition. It is essential to manage the condition effectively in young patients to ensure a good quality of life.

What is Eosinophilic Pleural Effusion (EPE), and how is it linked to Valproic Acid?

Eosinophilic Pleural Effusion (EPE) is a rare but serious condition characterized by an excessive accumulation of fluid in the pleural space, the area between the lungs and the chest wall. This fluid is filled with a high concentration of eosinophils, a type of white blood cell. The link to Valproic Acid (VPA) stems from VPA being a medication that has been associated with the development of EPE. While the exact mechanisms aren't fully understood, drug-induced EPE occurs when a medication, like VPA, triggers the condition. The case study mentioned in the text highlights this connection, illustrating how VPA treatment for bipolar disorder in a 15-year-old girl led to EPE.

What are the symptoms of Eosinophilic Pleural Effusion, and how should one respond if these appear while taking Valproic Acid?

The symptoms of Eosinophilic Pleural Effusion (EPE) can include shortness of breath, chest pain (especially when breathing), cough, and fever. These symptoms can also be associated with other conditions, which can make diagnosis challenging. If you or someone you know experiences these symptoms while taking Valproic Acid (VPA), it is crucial to seek immediate medical attention. Prompt recognition of symptoms and immediate medical attention are key to managing such situations effectively, as early intervention can significantly improve outcomes.

Besides Valproic Acid, what other factors can contribute to Eosinophilic Pleural Effusion?

Besides Valproic Acid (VPA), several factors can cause Eosinophilic Pleural Effusion (EPE), including infections and autoimmune diseases. The text emphasizes that drug-induced EPE can also occur as a result of taking particular medications. This is the case with VPA. It is important to note that while VPA is mentioned as a potential cause, other underlying conditions can also trigger EPE, underscoring the importance of thorough medical evaluation and accurate diagnosis.

What are the implications of being aware of the potential side effects of Valproic Acid, like Eosinophilic Pleural Effusion, especially for young people?

Being aware of the potential side effects of Valproic Acid (VPA), such as Eosinophilic Pleural Effusion (EPE), is crucial, especially for young people, due to the seriousness of the condition. It highlights the importance of open communication with healthcare providers, prompt recognition of symptoms, and immediate medical attention. This knowledge empowers individuals and their caregivers to make informed decisions about their health and well-being. By staying informed and proactive, potential risks can be managed effectively, ensuring that the patient receives the best possible care and support while taking VPA for bipolar disorder. The emphasis is on early intervention, which can improve outcomes significantly.