Medicines for Flu

Content provided by the Faculty of the Harvard Medical School

Medicines for Flu

There's a chill in the air, and schoolchildren are beginning to come home with the first colds of the year. Any time now, we will be into the thick of flu season. It is inevitable that some of us will suffer through the flu this year. Nonetheless, planning will help you.

What Can You Do About the Flu?

You can greatly lower your chances of getting the flu if you get a flu shot.

Several drugs are also available to help prevent and treat the flu. It is nice to have them as options, but these medicines aren't perfect solutions for the flu. After reviewing who needs a flu shot, I will tell you the not-so-simple story of flu medicines. They are not very commonly used.

Who Needs a Flu Shot?

The flu shot (influenza vaccine) is our best protection against the flu. Most people who get the flu shot avoid the flu entirely, and those who get the shot and then get flu have milder symptoms than they would have otherwise.

October is usually the earliest that flu shots become available each year. Until October 24, the U.S. Centers for Disease Control and Prevention recommends that only patients in high-risk groups receive flu shots. After this date, vaccination will be available to others. Get your shot as soon as you can, so it can protect you through the whole flu season. Most flu occurs in December, January and February.

In order to get the best protection, you need to get a new flu shot every year. Flu viruses shift their form over time, so every new flu season is unique. Each year, experts produce a new batch of influenza vaccine after sleuthing and careful prediction. This way, the protein mixture that is used in the vaccine can prepare us for the very strains of flu that are likely to be active during our flu season.

It is especially important for you to get vaccinated if:

• You are age 50 or older

• Your are 6 months to 23 months old

• You have diabetes, heart or lung disease, or impaired neurological function

• You have a brain injury or nerve problem that puts you at risk to aspirate (inhale saliva) when you have an illness with cough

• You have any medical illness that will require you to repeatedly visit a clinic or hospital during the flu season

• You work in a clinic or hospital

• You have an illness that suppresses your immune system, such as HIV

• You take medicine that suppresses your immune system, such as prednisone

• You are pregnant or you expect you may become pregnant before flu season ends. The flu shot is now recommended even for women who are in the first trimester of pregnancy, although this was not always the case.

• You are a child requiring daily aspirin treatment (it is helpful to prevent viral infections to avoid a complication known as Reye's syndrome)

• You live in a nursing home or facility shared by frail or elderly people

• You care for someone who is frail, or someone who is too young to receive the flu shot (an infant less than 6 months old)

Flu Vaccine in a Nose Spray

The flu vaccine is also available as a nasal spray, named FluMist. The nose spray form is just as effective as the shot for flu prevention.

While the shot contains proteins (not whole virus particles), the nose spray contains a live virus that is similar to real flu. This weakened virus strain, called an "attenuated" virus, has been specially cultivated by flu experts. It is too weak to cause symptoms, but it exposes your immune system to the same surface proteins that you would encounter if you were exposed to the real flu. This triggers your immune system to prepare itself so it can fight the flu.

A few specific groups of people can become ill even with this weakened virus, so they can't receive the nasal flu vaccine. You shouldn't get the nose spray if you are:

• Younger than 5

• 50 or older

• Pregnant

• A person with a weak immune system

• In frequent contact with a person who has a weak immune system

A person with asthma

Pills for Prevention Not Practical

If you do not get the flu shot and you are exposed to someone with cough, fever and muscle aches that suggest influenza, you may become interested in medicines that can prevent the flu.

Three medicines have been approved by the U.S. Food and Drug Administration for use after exposure to the flu, to prevent flu infection. They are oseltamivir (Tamiflu), amantadine (Symmetrel) and rimantadine (Flumadine). These three medicines are able to kill influenza virus particles. Oseltamivir is the most popular of the flu protection medicines; it has the fewest side effects, and it works against more varieties of influenza than do the other drugs.

If you take one of the medicines for a large portion of the flu season, it can help to keep you from getting the flu. However, flu season is a long season. If you want a pill to prevent flu for you, then you will have to take it for many days. This can get expensive and inconvenient.

Take oseltamivir (Tamiflu) as an example. The study that demonstrated a protective benefit from oseltamivir had people taking daily medication for a full six weeks.

Without oseltamivir, about one out of every 21 adults would have developed the flu in this study. Six weeks of oseltamivir whittled this statistic down to one person out of every 77 or so. Certainly, some individuals benefited from having the oseltamivir. However, many more people took the medicine and never really needed it. Scientists counted and concluded that at least 25 treated people or roughly 1,200 separate doses of oseltamivir (costing more than $8,000) were needed in order to successfully prevent a single case of flu.

For six weeks of treatment, the cost of this drug for an individual is approximately $300. Most people don't think the drug is worth the money. Certainly, if you can receive a flu shot, vaccination is a better way to get protection.

Some people try using oseltamivir for 10 days, if a person in their household gets sick with the flu. This shorter course of treatment costs about $75. This can help to protect you, but it can only protect you for those 10 days. If flu continues to be passed around within your community (in buses, in your grocery, or other places you may go), then you are still at risk. Just like a bicycle helmet, antiviral drugs can protect you only at the times you are using them.

Prevention drugs can be useful for people who spend most of their time in a closed community, such as a nursing home. Some experts recommend preventive treatment during a flu outbreak even if most or all of the individuals in a nursing home have received the flu vaccine, to give these older individuals the maximum protection. In order for prevention to work best, everyone in the facility needs to take oseltamivir or another prevention medicine at the same time, and they need to start treatment right after flu hits the center. This way, the flu outbreak in the facility does not last very long, and a reasonably short course of antiviral medicine can be used to protect the residents.

Medicines for Flu Treatment

If you receive the flu shot, you probably will have a very mild flu or no flu this year. If you don't get the flu shot, you might benefit from treatment with an antiviral medicine if you do get flu symptoms.

Oseltamivir, amantadine, rimantadine and one other antiviral drug, zanamivir (Relenza), can be useful for treatment of the flu.

Usual flu infection causes symptoms of fever, aches, cough, headache and nasal symptoms that last for about five days. If your symptoms are truly coming from flu, an antiviral medicine can reduce the length of symptoms to four days or so, so it can be a little bit helpful. However, these drugs work only if you take your first dose within 48 hours after the start of your symptoms. Also, they don't have an obvious benefit if your symptoms are mild, without a high fever on the first day of symptoms.

The cost of treatment is about $75 for oseltamivir and somewhat less for other medicines.

Any of these medicines can cause side effects. Oseltamivir causes nausea and vomiting in one out of every six people who take the medicine. Zanamivir (an inhaled medicine) can cause cough or wheeze, nose or throat irritation and should not be used by a person with lung disease. Amantadine and rimantadine can both cause insomnia, nervousness, lightheadedness and, in some cases, hallucinations. None of these drugs can be used during pregnancy.

Back to Basics

Most people do not use antiviral medicines to treat the flu. For almost anyone with flu, acetaminophen (Tylenol) is helpful. It can improve fever and chills, reduce aches, and help headaches.

Last updated:	September 05, 2008