Cold vs. Flu: How Are They Different?
The common cold and the flu share many of the same symptoms, but flu symptoms tend to be more severe. Here are the key differences between a cold and the flu.
Relenza
Used for Flu
Used for Flu
Relenza (zanamivir) is an antiviral medication. It can help ease flu symptoms and prevent the flu in certain adults and children. But it doesn't replace the seasonal flu vaccine. Relenza (zanamivir) comes as an inhaler that's inhaled by mouth twice daily for flu treatment or once daily for flu prevention. Because of the rare risk of bronchospasm, people who have asthma or chronic obstructive pulmonary disease (COPD) aren't recommended to use this medication. Common side effects include runny nose and dizziness. Relenza (zanamivir) is brand name only and not available as a generic medication.
What is Relenza (zanamivir)?
What is Relenza (zanamivir) used for?
- Flu treatment (flu types A and B) - age 7 years and older
- Flu prevention (flu types A and B) - age 5 years and older
How Relenza (zanamivir) works
Relenza (zanamivir) is an antiviral medication. Specifically, it's a neuraminidase inhibitor. It stops the release of flu virus from infected cells. This prevents the spread of the flu in the respiratory tract.
Drug facts
| Common Brands | Relenza |
|---|---|
| Drug Class | Antiviral |
| Controlled Substance Classification | Not a controlled medication |
| Generic Status | No lower-cost generic available |
| Availability | Prescription only |
Side effects of Relenza (zanamivir)
The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.
Common Side Effects
- Diarrhea (3%)
- Nausea (3%)
- Sinus infection (3%)
- Ear, nose, and throat infections (2%)
- Dizziness (2%)
- Bronchitis (2%)
- Headache (2%)
- Nose symptoms (2%)
- Cough (2%)
Less Common Side Effects
- Vomiting
Relenza (zanamivir) serious side effects
Contact your healthcare provider immediately if you experience any of the following.
- Bronchospasm: difficulty breathing, coughing, or chest tightness
- Allergic reaction: severe rash or throat swelling
The following Relenza (zanamivir) side effects have also been reported
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
Rare
Convulsions
dizziness and fainting
fast, slow, or irregular heartbeat
flushing or reddening of the skin
increased sensitivity to sunlight
itching, pain, redness, swelling, or watering of the eye or eyelid
joint pain
severe skin rash or hives
shortness of breath or troubled breathing
swelling or puffiness of the face
swollen glands or tightness in the throat
tightness in the chest or wheezing
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Get your GoodRx coupon
$75.48
GoodRx discount
$62.89
Pros and cons of Relenza (zanamivir)
Pros
- Works for influenza types A and B
- Inhaled; good option for people who don't like to take pills
- Can prevent household members from spreading the flu to each other
Cons
- Not recommended for people with asthma or COPD because of risk of bronchospasm
- Need to start early for it to work well (within 2 days of symptoms appearing)
- Won't stop the spread of flu to others, if you're already sick with the flu
Pharmacist tips for Relenza (zanamivir)
- Each blister of Relenza contains 5 mg of zanamivir. Since the typical dose of Relenza (zanamivir) is 10 mg, you need to use two blisters and do two separate inhalations (puffs) for each dose.
- Ask your pharmacist for a demonstration so that you know how to use Relenza (zanamivir). If needed, follow the detailed directions in your medication guide. If you're having a difficult time using this inhaler, talk with your healthcare team about other options.
- If you're prescribed Relenza (zanamivir) for flu treatment, start taking it as soon as possible, ideally within 2 days of when the symptoms first appear. This medication works by stopping the spread of flu virus in your respiratory tract so it's less effective if the virus has already spread.
- If you're taking Relenza (zanamivir) for treatment, try to take the 2 doses a day 12 hours apart at the same time every day. This will help keep the amount of medication in your lungs at the right level.
- Taking Relenza (zanamivir) can help shorten the lenghth of time you're sick with the flu or prevent you from catching the flu. But if you're already sick with the flu, you can still pass it on to other people. If you're sick with flu symptoms, it's best to avoid contacting other people and staying home to rest until you feel better. If you need to be around other people, you're recommended to wear a mask.
- Let your healthcare team know if you've recently received FluMist (the nasal spray flu vaccine). This is a live vaccine. You can't take Relenza (zanamivir) if it has been less than 2 weeks since you received FluMist.
- Relenza (zanamivir) doesn't replace the flu vaccine. The vaccine is still the first-choice option to prevent the flu. But Relenza (zanamivir) might be an option if you're not able to get the flu vaccine.
Risks and warnings for Relenza (zanamivir)
Relenza (zanamivir) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Bronchospasm (tightening of the airways)
- Risk factors: People with lung conditions like asthma or COPD
Avoid using Relenza (zanamivir) if you have asthma, COPD, or other airway conditions. Though rare, people who used this medication have reported bronchospasms. This condition can be life-threatening, especially for people who already have airway problems. If you do have an airway condition and choose to take Relenza (zanamivir) after discussing the risks and benefits with your healthcare team, you care team will monitor your breathing closely and ask you to keep a rescue inhaler with you at all times. Stop this medication immediately and get medical help if you experience difficulty breathing, coughing, shortness of breath, wheezing, or chest tightness.
Allergic reactions
- Risk factors: Prior severe allergic reaction to Relenza (zanamivir)
It's rare, but some people have allergic reactions after taking Relenza (zanamivir). Symptoms can include a blistering rash, throat swelling, difficulty breathing, or shock. Go to the emergency room right away if this happens.
Unusual thoughts or behavior
Risk factors: Flu infection
There have been reports of people having seizures, hallucinations, and delirium, after starting Relenza (zanamivir) and other similar medications. Sometimes, these neurologic symptoms have led to harm. It's difficult to know if these symptoms are a side effect of the medication because the flu itself might also cause similar effects. If you notice signs of unusual thinking or behavior, or experience seizures, let your healthcare professional (HCP) know right away. They'll consider the risks and benefits of continuing Relenza (zanamivir).
Proper use of Diskhaler
It's important that Relenza (zanamivir) is inhaled properly through the Diskhaler that it comes with. The inhalation powder that comes in the blister pack should never be mixed and used as a solution. It shouldn't be given by a nebulizer or inhaled in any other way than instructed by a healthcare professional.
Relenza (zanamivir) dosage
The average cost for 1 inhaler of 5mg of Relenza (zanamivir) is $62.89 with a free GoodRx coupon. This is 16.68% off the average retail price of $75.48. 
Inhaler
Inhaler| Dosage | Quantity | Price as low as | Price per unit |
|---|---|---|---|
| 5mg | 1 inhaler | $62.89 | $62.89 |
Typical dosage for Relenza (zanamivir)
Each inhalation of Relenza gives 5 mg of zanamivir. You'll need to inhale Relenza twice for a 10-mg dose.
- Flu treatment (adults and children ages 7 or older): It's important to start this medication no later than 2 days after you start having symptoms. The typical dose is 10 mg inhaled by mouth twice daily for 5 days.
- Flu prevention (adults and children ages 5 or older): Start this medication as soon as possible when others around you start having symptoms. The typical dose is 10 mg inhaled by mouth once a day. Your care team might instruct you to take this medication for 10 days if others in your household have the flu, or for 28 days if there's a flu outbreak in your community.
Interactions between Relenza (zanamivir) and other drugs
Relenza (zanamivir) may interact with certain medications or supplements. Always let your doctor and pharmacist know about any other medications or supplements (including prescribed and over-the-counter medications, vitamins, and dietary or herbal supplements) that you are currently taking. The list below does not include all possible drug interactions with Relenza (zanamivir). Please note that only the generic name of each medication is listed below.
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.
How much does Relenza (zanamivir) cost?
To access savings, use a GoodRx coupon and pay just a fraction of the retail price.
Relenza (brand)
$62.89
Relenza (zanamivir) contraindications
Contraindications are specific health conditions or situations in which a person should not take a medication due to safety concerns. If you have any of the following conditions or if any of the following apply to you, let your healthcare provider know because Relenza (zanamivir) will not be safe for you to take.
- Allergy to milk proteins
What are alternatives to Relenza (zanamivir)?
There are a number of medications that your doctor can prescribe in place of Relenza (zanamivir). Compare a few possible alternatives below.
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