Ergotamine belongs to a family of lysergic acid derivatives that are produced from ergot alkaloids. These chemicals are useful for the treatment of severe migraine and cluster headaches. The mechanism of action of ergot alkaloids is vasoconstriction and they work by decreasing the flow of blood in the brain. Caffeine is commonly used in combination with the ergot alkaloids to increase adsorption. Side effects can be very serious and include anxiety, vision problems, chest pains, increased blood pressure, and pain in the arms and legs.