Aspirin is a pain reliever, as well as an anti-inflammatory and a fever reducer.

Butalbital is in a class of drugs called barbiturates that slow down your central nervous system (brain and nerve impulses) and cause relaxation.

Caffeine is believed to constrict dilated blood vessels (veins and arteries) that may contribute to tension headaches.

Fortabs is used to relieve complex tension headaches, although precisely how it works is unknown.

Fortabs may also be used for purposes other than those listed in this medication guide.

Most important: Use caution when driving, operating machinery, or performing other hazardous activities. Butalbital may cause drowsiness or dizziness. If you experience drowsiness or dizziness, avoid these activities.

Avoid alcohol. Alcohol taken during therapy with Fortabs can increase the risk of stomach bleeding and can increase drowsiness and dizziness.

Never take more Fortabs than is prescribed for you. If your pain is not being adequately treated, talk to your doctor.

Avoid other over-the-counter and prescription products that contain aspirin. Too much aspirin could be dangerous. Talk to your doctor or pharmacist before taking any over-the-counter preparations.