Matthew S. Robbins, MD, FAAN, responds:
Aspirin and other over-the-counter painkillers are ineffective against cluster headache, so named because attacks usually occur in clusters that can last for weeks or months. Fortunately, neurologists have several options for both treating and preventing cluster headache, an excruciatingly painful but less common headache disorder than migraine.
Pattern of Attack
Cluster headache attacks involve the trigeminal autonomic reflex, in which pain on one side activates the parasympathetic nerves of the face, triggering involuntary symptoms such as tearing, runny nose, red eye, flushing, a droopy eyelid, and a sense of fullness in the ear. People experiencing an attack may appear agitated and restless and may pace or rock back and forth in a chair.
Risk Factors
Several factors may increase the risk of cluster headache, including gender (men are three times more likely to experience cluster headache than women) and age (most people develop these headaches between the ages of 20 and 50). Other associations include smoking (people with cluster headache are more likely to be smokers), alcohol consumption (which can trigger an attack in those at risk), and family history (those who have a close relative who experiences cluster headache may have an increased risk).
Treatments
OXYGEN. To shorten attacks, doctors may prescribe 100 percent oxygen.
TRIPTANS. These selective serotonin receptor agonists block pain signals and the release of other natural chemicals that cause pain. Sumatriptan (Imitrex) can be injected or administered as a nasal spray. The triptan zolmitriptan (Zomig) can also be used as a nasal spray. Triptans are not recommended for people with a heart condition or a history of stroke or transient ischemic attack.
VAGUS NERVE STIMULATOR. Last year the US Food and Drug Administration approved a handheld, patient-operated device called gammaCore that's placed on the vagus nerve near the neck to stimulate certain neurons, which may lead to a reduction in pain. In two clinical trials, the device appeared to be safe and to work for episodic cluster headache.
Prevention
STEROID INJECTION. Doctors may inject a steroid, sometimes with a numbing agent, into the occipital nerve at the back of the head to relieve pain while waiting for longer-term therapies to take effect.
CALCIUM CHANNEL BLOCKERS. Verapamil, a calcium channel blocker used to lower blood pressure, seems to be effective in reducing the frequency of attacks. Side effects can include constipation, nausea, low blood pressure, and low pulse.
CORTICOSTEROIDS. These anti-inflammatories may work quite well but are usually used short-term because of possible serious side effects including diabetes, high blood pressure, cataracts, and bone disease.
LITHIUM. Rarely a first choice because of side effects such as tremor, diarrhea, and thyroid and kidney toxicity, lithium may be prescribed if other drugs don't work or can't be used. If you take lithium, you'll need to have regular blood tests to monitor sodium levels, thyroid hormones, and kidney function.
Research
Clinical trials are underway to test the use of monoclonal antibodies (synthetic molecules that can attach to specific proteins in the body to block their function) to prevent cluster headache. Researchers think sumatriptan may be effective because it decreases levels of calcitonin gene-related peptide (CGRP), which is released during attacks and causes pain. The hope is that the antibodies could attach to the CGRP molecule or its receptors in the trigeminal nerve and small blood vessels and prevent the peptide from leading to pain.