You may be treated for encephalitis in a hospital's intensive care unit. During your stay, your vital signs (blood pressure, heart rate, breathing, and level of body fluids) will be closely monitored. Treatment will depend on your symptoms and the particular cause of encephalitis, if the cause can be determined.

Encephalitis caused by the herpes simplex virus or the chickenpox (varicella-zoster) virus is treated with the antiviral medication acyclovir, which is given in a vein (intravenous, or IV).¹ It is important to start acyclovir treatment as soon as encephalitis is suspected, even if the exact cause of the illness is not known. This is because early treatment makes it more likely that you will get better.

Call your doctor immediately if you think you have symptoms of encephalitis, such as a sudden and severe headache, fever, and confusion, especially if you also have a stiff neck, nausea, vomiting, and drowsiness. Treatment works best when given early in the illness.

Some health professionals also are using the herpes zoster (shingles) medication valacyclovir for herpes simplex encephalitis, even though this medication has not officially been approved for the treatment of encephalitis (unlabeled use).

Encephalitis caused by arboviruses, which are carried by mosquitoes and ticks, will not respond to acyclovir or other medications. Instead of trying to kill the virus, doctors treat the symptoms so that you are comfortable and the body can heal itself.

• High fever may be reduced with acetaminophen (Tylenol) or nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, aspirin, or naproxen. However, a mild fever may actually promote healing and is usually not treated. Aspirin should not be given to anyone younger than 20 because of the risk of Reye's syndrome.
• Seizures may be controlled with anticonvulsant medications such as phenytoin (Dilantin) or phenobarbital.
• A machine to help you breathe (ventilator) and other supportive measures may be needed if you go into a coma.