Medications used for prevention

The Food and Drug Administration has approved four drugs for prevention of migraine:

• Propanolol (Inderal)
• Timolol (Blacadrene)
• Divalproex sodium (Depakote)
• Topiramate (Topamax)

Propanolol and timolol are beta-blocker drugs. Divalproex and topiramate are anti-seizure drugs. Many other drugs are also being used or investigated for preventing migraines.

Beta-Blockers

Beta-blockers are usually prescribed to reduce high blood pressure. Some beta-blockers, however, are also useful in reducing the frequency of migraine attacks and their severity when they occur. Propranolol (Inderal) and timolol (Blocadren) have been approved specifically for prevention of migraine. Metoprolol (Toprol), atenolol (Tenormin), and nadolol (Corgard) are also being studied for migraine prevention.

Side Effects. Side effects may include:

• Fatigue and lethargy are common.
• Some people experience vivid dreams and nightmares, depression, and memory loss.
• Dizziness and lightheadedness may occur upon standing.
• Exercise capacity may be reduced.
• Other side effects may include cold extremities, asthma, decreased heart function, gastrointestinal problems, and sexual dysfunction.

If side effects occur, the patient should call a doctor, but it is extremely important not to stop the drug abruptly. Some evidence suggests that people with migraines who have had a stroke should avoid beta-blockers.

Anti-Seizure Drugs

Anti-seizure drugs, also called anti-epileptic drugs or anticonvulsants, affect the neurotransmitter gamma aminobutyric acid (GABA), which helps prevent nerve cells from over-firing. GABA may also have a role in migraines. These drugs are commonly used for epilepsy and bipolar disease. Anti-seizure drugs are more expensive than other drugs. They also have significant side effects. Divalproex sodium (Depakote) and topiramate (Topamax) are the only anti-seizure drugs that are approved for migraine prevention. However, if patients do not respond to either of these drugs, doctors may try other types of anti-seizure medications.

Divalproex Sodium (Depakote). Divalproex sodium (Depakote) was first approved in 1996 for migraine prevention. A once-a-day formulation of divalproex (Depakote ER) was approved in 2000. Doctors sometimes prescribe a similar drug, valproate (Depakene). Pregnant patients should not use these drugs, as they may cause birth defects.

Topiramate (Topamax). In 2004, the Food and Drug Administration approved topiramate for prevention of migraines in adults. Studies from 2006 indicated that the drug works well when used on a long-term basis. Patients in these studies experienced significantly fewer migraines for up to 14 months. Topiramate’s most common side effect is a tingling sensation in the arms and legs. Weight loss is also a side effect. In clinical trials, patients lost an average of 3.8% of their body weight.

Other Anti-Seizure Drugs Under Investigation. Researchers are studying other types of anti-seizure drugs for migraine prevention. These include levetiracetam (Keppra), gabapentin (Neurontin), pregabalin (Lyrica), zonisamide (Zonegran), tiagabine (Gabitril), and the investigational drug lacosamide (LCM).

Side Effects. Anti-seizure medication's side effects vary by drug but may include:

• Nausea and vomiting
• Diarrhea
• Cramps
• Hair loss
• Dizziness
• Sleepiness
• Blurred vision
• Weight gain
• Valproate and divalproex can cause serious side effects of inflammation of the pancreas (pancreatitis) and damage to the liver

Tricyclic and Other Antidepressants

Amitriptyline (Elavil, Endep), a tricyclic antidepressant drug, has been used for many years as a first-line treatment for migraine prevention. It may work best for patients who also have depression or insomnia. Tricyclics can have significant side effects, including disturbances in heart rhythms, and can be fatal in overdose. Although other tricyclic antidepressants may have fewer side effects than amitritpyline, they do not appear to be particularly effective for migraine prevention.

Researchers have investigated newer types of antidepressants, including serotonin-reuptake inhibitors(SSRIs), such as fluoxetine (Prozac). However, studies to date do not indicate that SSRIs are helpful for migraine prevention.

Other Investigational Treatments for Preventing Migraines

Muscle Relaxants. Botulinum toxin A (Botox) injection, a common wrinkle treatment, causes small muscles to relax. This approach is now being used with some success for treating disorders that involve over-excited muscle activity, including myofascial pain syndrome and migraine. One study reported complete migraine relief in more than half of patients being tested and improvement of more than 50% in another 35% of patients. Relief lasted 3 - 4 months with no adverse effects. A study presented at the 2005 meeting of the American Headache Society reported that patients who regularly received Botox injections every 3 months reduced both the frequency of migraine attacks and their reliance on pain medications

Angiotensin Converting Enzyme Inhibitors. Commonly used for treating high blood pressure, angiotensin converting enzyme (ACE) inhibitors block the production of the protein angiotensin, which constricts blood vessels and may be involved in migraine. Studies using the ACE inhibitor lisinopril (Prinivil, Zestril) are reporting significant reduction in migraine attacks.

Angiotensin-Receptor Blockers. Angiotensin-receptor blockers (ARBs) have actions similar to ACE inhibitors, but may have fewer side effects. In one study, patients who took the ARB candesartan (Atacand) had significantly fewer headaches compared to patients who received placebo.

Neurostimulation Devices. Researchers are investigating a transcranial magnetic stimulation (TMS) device to help stop migraines before they occur. The hair dryer-size device is held to the back of the head and delivers quick magnetic pulses. The device is used when a patient experiences the first signs of a migraine. Other types of nerve stimulation devices are also under investigation.

Inhalation Devices. These devices use heat to vaporize a drug so that it can be inhaled into the lungs. Clinical trials are currently testing this device with procholorperazine (Compazine), a tranquilizer drug that is used to treat nausea and vomiting.

Nasal Devices. New types of nasal sprays and powders are being researched. Some of them use capsaicin, the chemical found in cayenne peppers, to help relieve pain.

Skin Patches. The Actyve transdermal patch uses a small battery-powered system to deliver a triptan drug through the skin.

Drugs. New drugs in development include tonabersat (gap junction blocker), trexima (combination triptan and non-steroidal anti-inflammatory drug), and GW274150 (nitric oxide synthase inhibitor).