Q. How do I know which preventive medication is appropriate for migraine prevention?
More than 2,000 prescription drugs are currently available in the United States. Based on my experience, 50 to 75 of these medications are commonly used to treat migraine. These drugs can be divided into two basic groups: “acute” medications, which patients consume only when they experience a migraine attack; and “preventive” drugs, which patients ingest every day in an effort to decrease attack frequency, severity and duration.
Virtually every day someone asks me, “Why did my doctor prescribe this drug for me?” What patients really want to know is why their physician picked this particular medication, as opposed to some other drug. Patients are typically most concerned about preventive drugs because these agents are used every day, which increases awareness about the drug including adverse effects, costs, effectiveness and other factors. I encourage all patients to discuss with their doctor the reason(s) why a specific drug is prescribed, because only the physician knows the precise answer.
Nevertheless, physicians take a number of common principles into account when selecting a drug, especially when it comes to preventive medications. It is important for physicians treating headache conditions to start by reviewing the patient’s complete medical history. This information can help illuminate which medications are suitable or inappropriate.
Ideally, physicians can prescribe one drug to treat more than one illness. For example:
- High blood pressure is one of the most common risk factors for heart disease and one of the most common chronic illnesses in the United States. It affects millions of people, including migraineurs. It is appropriate for these patients to be prescribed migraine medications that also help lower blood pressure and improve heart function; such medications include beta-blockers (e.g., propranolol or timolol) or calcium channel blockers (e.g., verapamil).
- If a person suffers with seizures and migraines, then anti-seizure drugs (e.g., topiramate or divalproex) would be excellent choices.
- People with depression and migraine are candidates for numerous anti-depressant drugs (e.g., venlafaxine or fluoxetine).
- A person with insomnia and migraine could benefit from a sedating medication such as the tricyclic antidepressant agents (e.g., amitriptyline).
- Conversely, someone who is sleepy throughout the day and has migraine might benefit from a drug that causes anxiousness (e.g., buproprion).
- Individuals with depression, insomnia and migraine could benefit from a drug that reduces depression and causes sedation (e.g., nortriptyline or amitriptyline).
I have highlighted some of the scenarios frequently encountered when treating migraine, but the list of possible illnesses is lengthy. The basic goal is to maximize the number of diseases treated with each prescribed drug.
It is equally important for physicians to avoid certain medications based on the patient’s condition. For example, the majority of migraine sufferers are women of childbearing age. If a woman is planning to get pregnant or becomes pregnant, then drugs incompatible with pregnancy must not be prescribed. The Food and Drug Administration assigns a pregnancy category rating to all medications (A, B, C, D or X). Ideally, only drugs ranked A or B would be used during pregnancy, with C drugs used only if the benefits outweigh the risks. Drugs ranked D (e.g., topiramate and divalproex) should be avoided during pregnancy except in extreme situations, while drugs ranked X (e.g., dihydroergotamine) are never to be used during pregnancy.
In another scenario, someone who needs high exercise tolerance, such as a marathoner, should avoid agents that lower blood pressure (e.g., beta-blocker or calcium channel blockers). If an individual already has problems with alertness and staying awake, then sedating drugs are not the best choice. Similarly, if someone suffers with anxiety, medications that can cause anxious feelings (e.g. buproprion) are poor choices. Again, numerous situations can exist, and I have only highlighted some frequent problems.
Physicians must also consider duration of action, or how often a drug must be consumed. People are more successful at consistently taking medication once a day than taking a drug that needs to be consumed two, three, or even four times per day. The majority of headache preventive drugs are available as once-a-day (some twice-a-day) formulations. To promote convenience, ask your physician to prescribe once-a-day medications whenever possible.
And of course, cost is an important factor. All medications cost money, although this cost can vary greatly. Your insurance coverage (if any) is important and this information should be shared with the physician. Ideally, the physician will ensure that your insurance agency will pay for the drug before you leave the physician’s office with a prescription for the pharmacy; correcting insurance-coverage problems at the pharmacy counter is often a time-consuming and frustrating process that is best avoided. If you lack the ability to pay for medications, talk to a health care professional such as a physician or pharmacist— many pharmaceutical companies offer patient-assistance programs. Generally speaking, generic medications are equally effective but cheaper than brand name options. Use these if possible. Your health care professional can help direct you toward a medication that is less expensive but will help improve your illness.
Ultimately the question “Why did my doctor prescribe this drug for me?” is still best answered by your physician. But it’s important to understand that a drug may or may not be selected based on how it can benefit (or worsen) your current condition.
Richard Wenzel, PharmD, is a staff pharmacologist at the Diamond Headache Unit, St. Joseph Hospital, in Chicago, Ill.
