Corticosteroids (such as prednisone or dexamethasone) are referred to as "transitional" medicines for the treatment of cluster headaches because they are sometimes used to break a cycle of cluster headaches. They are paired with medicines that stop (abortive) or prevent (prophylactic) additional headaches during a headache cycle. Often, within 2 to 4 days after starting treatment with corticosteroids, you will become headache-free. By the time the corticosteroids are stopped—their use is often tapered within 6 to 8 weeks of starting and then discontinued—the medicines used to prevent cluster headaches, such as verapamil, have taken effect.

Corticosteroids are not used over a long period of time because they can cause serious side effects, including:

• Weight gain.
• High blood pressure.
• High blood sugar levels.
• Cataracts.
• Osteoporosis.
• Stomach ulcers.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)