Zanamivir: Uses, Benefits, Side Effects and More

Introduction to Zanamivir

Zanamivir is an antiviral medicine used to treat and prevent influenza. It works against both influenza A and B viruses. Sold under the brand name Relenza, zanamivir belongs to a group of drugs known as neuraminidase inhibitors. These medicines stop the flu virus from spreading inside the body. They do this by blocking the viral enzyme neuraminidase. This enzyme helps new virus particles escape from infected cells. When it’s blocked, the virus can’t spread as easily. Zanamivir is given as an inhaled powder. It goes straight into the lungs, where the virus grows. This targeted action helps it work quickly and may reduce side effects in the rest of the body.

How Zanamivir is Used

Zanamivir is approved to both treat and prevent the flu. For treatment, it works best if started within 48 hours of flu symptoms appearing. Taking it early can shorten how long the illness lasts. It may also reduce symptoms like fever, cough, sore throat, and body aches. In most cases, it cuts the illness short by one or two days.

Doctors prescribe zanamivir for people aged 7 years and older to treat flu. It can also be used to prevent flu in people 5 years and older. This includes people who are at high risk of flu complications, like older adults, those with long-term health problems, or people with weak immune systems. It’s also useful in places where flu spreads quickly, such as nursing homes, schools, and hospitals.

Zanamivir also works well for prevention. It can be given after someone is exposed to the flu, such as when a family member is sick. It can also be used during flu outbreaks when vaccines are not enough or when someone can’t get the flu shot. While flu vaccines remain the first line of defense, zanamivir adds another layer of protection for high-risk groups.

Benefits of Zanamivir

There are several advantages to using zanamivir. Because it is inhaled, the drug acts directly in the lungs. This can reduce how much of it enters the bloodstream. As a result, there may be fewer side effects compared to pills or injections. This also makes zanamivir a better choice for people who can’t take oral medicine or who have kidney or liver issues.

Another benefit is that zanamivir treats both types of seasonal flu—type A and type B. It can help reduce the spread of flu in families or crowded places. For people with low immune responses, like the elderly or those with cancer, zanamivir can help protect against flu when vaccines don’t work well enough.

In summary, zanamivir offers:

• A way to reduce the length and severity of flu illness

• A method for preventing flu after close contact

• An option for people who can’t take oral antivirals

• A treatment that works directly in the lungs

Dosage and How to Take It

Zanamivir is taken using a special device called a Diskhaler. This device delivers a dry powder form of the drug. Each dose is two inhalations of 5 mg, totaling 10 mg per dose. For flu treatment, it is taken twice a day for five days. For prevention, the dose is 10 mg once daily, usually for 10 days after exposure, or longer if there’s an ongoing outbreak.

Using the Diskhaler properly is important. The powder must reach deep into the lungs to work well. People using the device should be shown how to use it correctly. This can be hard for young children or older adults. In some cases, help from a caregiver or nurse may be needed.

People with a stuffy nose or blocked airways may not get the full dose. It is best to use the medicine when breathing is clear. Those using other inhalers, like bronchodilators, should use them before zanamivir to open up the lungs.

Common and Rare Side Effects

Zanamivir is safe for most people and causes only mild side effects. These effects usually go away after a short time. Common issues include:

• Headache

• Throat irritation

• Cough

• Nose congestion or a runny nose

Some people might have nausea or mild stomach upset. Dizziness or sinus pain is also possible. Most of these side effects are related to the drug being inhaled into the lungs.

However, there are some rare but serious side effects. In people with asthma or other breathing problems, zanamivir can cause bronchospasm. This means the airways tighten, making it hard to breathe. Because of this, it is not advised for people with uncontrolled asthma or severe chronic lung disease unless clearly needed.

Serious allergic reactions are very rare. These may include rash, swelling, or trouble breathing. In some children, there have been reports of confusion or strange behavior, but it is unclear whether zanamivir or the flu itself caused these problems. Caregivers should keep a close watch on children using this medicine.

Important Warnings and Safety Advice

Zanamivir is not for everyone. People with lung conditions like asthma or COPD should be careful. If they need to use it, they should also have a fast-acting inhaler on hand in case of breathing problems.

The powder in zanamivir contains lactose. People with severe lactose allergies should avoid it. Though reactions are rare, it’s best to check with a doctor first.

The Diskhaler should never be shared between people. Sharing could spread the flu virus from person to person. Zanamivir is not a cure for colds or other viral infections. It also does not replace the flu vaccine. Everyone who can get vaccinated should still do so.

People who can’t use the inhaler properly may not benefit from zanamivir. This includes very young children, the very ill, or anyone on a breathing machine. In these cases, other flu treatments may be a better choice.

Pregnancy, Breastfeeding, and Children

Flu during pregnancy can be serious, especially later in pregnancy. Zanamivir can be used in pregnant women when the benefits outweigh the risks. It is not known to harm unborn babies in animal studies, but human data is limited.

Breastfeeding mothers should talk to their doctor. Small amounts of the drug may pass into breast milk, but the risk to infants is thought to be low.

For children, zanamivir is approved for treatment starting at age 7 and for prevention from age 5. Children must be able to use the inhaler properly. If not, another treatment may be better.

Drug Resistance and Interactions

Resistance to zanamivir is rare but can happen. Flu viruses can change, especially in people with weak immune systems who have longer infections. To lower this risk, patients should take the full course as prescribed.

Zanamivir has very few drug interactions. This is because it is not absorbed much into the bloodstream. It does not affect the liver or kidneys and doesn’t interfere with most other medicines. However, if someone is using other inhaled drugs, they should time them properly. A bronchodilator should always be used before zanamivir.

How Well Does It Work?

Studies show that zanamivir helps reduce flu symptoms when started early. People who take it usually feel better faster and miss fewer days of work or school. They also have fewer flu-related complications like ear infections or bronchitis.

As a preventive drug, zanamivir lowers the chance of getting sick after exposure. In nursing homes and households, it helps stop flu outbreaks. When flu shots aren’t enough—such as in years with poor vaccine matches—zanamivir gives extra protection.

Zanamivir is not a cure for the flu, but it helps people get better faster and lowers the chances of passing the virus to others.

Storage, Access, and Use

Zanamivir should be kept at room temperature and in a dry place. The Diskhaler should be stored in its case until it is used. Wash hands before and after using the device.

The medicine is available by prescription only. Health insurance plans often cover it, especially during flu season. It should always be used under a doctor’s guidance. Patients should not share the device or use expired medication.