Corticosteroids and antiseizure medicines (anticonvulsants)

Corticosteroids and antiseizure medicines (anticonvulsants) are commonly used for people with brain and spinal cord tumours. They do not treat the tumour but help lessen the symptoms caused by the tumours and their treatment.


Corticosteroids, such as dexamethasone (Decadron, Dexasone), are used to lessen increased intracranial pressure and control swelling in the brain (cerebral edema) or around the spinal cord (spinal edema). Swelling is caused by the growing tumour pressing on areas of the brain or spinal cord. Normal tissue may also swell as a reaction to surgery or radiation.

Corticosteroids can also help treat symptoms, such as headaches or other pain and nausea or vomiting. The drug is given at the lowest effective dose for each person and is gradually lessened until treatment is finished. No corticosteroids are given after treatment is done.

Side effects of corticosteroids include:

  • increased risk of infection
  • digestive problems such as nausea and heartburn
  • increased blood sugar levels
  • increased appetite and weight gain
  • mood changes, restlessness, excitement or nervousness

Antiseizure medicines (anticonvulsants)

Antiseizure medicines (anticonvulsants) are used to prevent seizures. Seizures are common in people with a brain tumour and may occur before diagnosis and during the course of the disease. Antiseizure drugs such as phenytoin (Dilantin) are given to people with brain tumours who have already had a seizure. Usually, antiseizure drugs are not given to prevent seizures in people who have not had them.

The level of the antiseizure drug in the blood is checked with regular blood tests. To be safe and effective, the drug level must stay within a certain range.

Side effects of antiseizure drugs include:

  • dizziness
  • drowsiness
  • skin rash or itching
  • swollen, painful and bleeding gums
  • nausea or vomiting

Tell your healthcare team if you have these side effects or others you think might be from medications. The sooner you tell them of any problems, the sooner they can suggest ways to help you deal with them.

Expert review and references

  • American Cancer Society. Treating Brain and Spinal Cord Tumors in Adults. 2020:
  • Fields MM, ARmstrong T. Central nervous system cancers. Yarbro CH, Wujcik D, Gobel B (eds.). Cancer Nursing: Principles and Practice. 8th ed. Burlington, MA: Jone & Bartlett Learning; 2018: Ch. 49.
  • National Comprehensive Cancer Network . NCCN Clinical Practice Guidelines in Oncology: Central Nervous System Cancers Version 1.2023. 2023.
  • PDQ® Adult Treatment Editorial Board. Adult Central Nervous System Tumors Treatment (PDQ®) – Health Professional Version. Bethesda, MD: National Cancer Institute; 2023:
  • Youngblood MW, Magill ST, Stupp R, Tsien C. Neoplasms of the central nervous system. DeVita VT Jr, Lawrence TS, Rosenberg S. eds. DeVita Hellman and Rosenberg's Cancer: Principles and Practice of Oncology. 12th ed. Philadelphia, PA: Wolters Kluwer; 2023: Kindle version, [chapter 64],

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