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Relenza vs Xofluza
Introduction
For patients dealing with the influenza virus, certain antiviral drugs can help in controlling and managing flu symptoms. Relenza and Xofluza are two such medications often prescribed for treating the flu. Each impacts different stages of the viral replication process but both aim to shorten the duration of illness and potentially reduce complications.
Relenza (zanamivir) works by inhibiting neuraminidase, an enzyme found on the surface of influenza viruses that enables them to escape from infected cells and spread throughout your body. It is typically administered through inhalation.
Xofluza (baloxavir marboxil), on the other hand, has a slightly different mechanism - it blocks an enzyme within the virus called cap-dependent endonuclease which is necessary for viral replication early in its lifecycle. This halts further growth of any existing infection while also preventing new infections from occurring. Unlike Relenza, Xofluza comes in tablet form.
What is Relenza?
Zanamivir (the generic name for Relenza) was one of the first neuraminidase inhibitors developed to combat influenza, marking a significant advancement over earlier antiviral medications. It received FDA approval in 1999. Zanamivir works by blocking an enzyme on the surface of the virus called neuraminidase, thereby preventing the virus from spreading within your body. This drug is used for both prevention and treatment of flu.
Baloxavir marboxil (referred to as Xofluza), approved by the FDA in 2018, represents another step forward in treating flu infections. Unlike zanamivir that inhibits viral spread after it has begun multiplying, baloxavir acts at an earlier stage by directly inhibiting flu replication via selective inhibition of viral cap-dependent endonuclease activity.
Both drugs have their side effects with zanamivir sometimes causing bronchospasm or worsening lung function, especially in people who already have chronic respiratory diseases like asthma or COPD while baloxavir can cause diarrhoea and bronchitis related symptoms.
What conditions is Relenza approved to treat?
Relenza is approved for treatment of different influenza variants:
- Influenza A and B, in adults and children aged 7 years and older who have been symptomatic for no more than two days
- Prevention of influenza A and B in adults and adolescents aged 5 years and older
Similarly, Xofluza is also authorized to treat:
- Uncomplicated influenza in patients aged 12 years or more who have been symptomatic for no more than two days.
- Post-exposure prophylaxis of influenza A or B virus infection following contact with an individual who has the flu. This applies to people 12 years of age or older.
How does Relenza help with these illnesses?
Relenza functions to control influenza by inhibiting the activity of neuraminidase, an enzyme found on the surface of influenza viruses. This enzyme helps new viral particles to depart from infected cells and continue spreading throughout the body. By inhibiting neuraminidase, Relenza prevents new virus particles from leaving host cells, thus containing the spread of infection within localized areas. Neuraminidase is a protein that plays an essential role in viral replication and release, enabling the virus to propagate throughout your system; its inhibition can limit flu symptoms and shorten recovery time.
On the other hand, Xofluza works differently but also aims for controlling influenza. It operates by blocking an enzyme called cap-dependent endonuclease which is necessary for viral replication inside host cells. Unlike Relenza which acts on virus after it has multiplied and attempts to spread further into your system, Xofluza stops multiple cycles of flu virus replication within infected cells at early stages itself hence preventing widespread propagation before it actually begins.
What is Xofluza?
Xofluza, also known as baloxavir marboxil, is a unique antiviral medication that inhibits cap-dependent endonuclease activity of the flu virus and halts its replication. It was first approved by the FDA in 2018. Unlike Relenza which requires an inhaler for administration and can be inconvenient or challenging to use for some individuals, Xofluza is taken orally with a single dose making it easier to administer especially for those who have difficulty using inhalers or are otherwise unable to do so.
Furthermore, Xofluza's mechanism of action means that it has been found effective against both influenza A and B viruses including strains resistant to other types of antiviral drugs like Relenza. This makes it particularly beneficial in treating various forms of the flu where other medications may not work as effectively. The primary side effects reported with Xofluza are diarrhea and bronchitis symptoms; however, its overall side-effect profile appears favorable compared to many other flu treatments.
What conditions is Xofluza approved to treat?
Xofluza is approved by the FDA for the treatment of:
- Influenza type A and B (commonly known as "the flu") in patients aged 12 years and older who have shown symptoms for no more than 48 hours.
- Post-exposure prevention of influenza A and B in people aged 12 years and above following contact with an individual who has the flu.
How does Xofluza help with these illnesses?
Xofluza is an antiviral medication that works by inhibiting the replication of the influenza virus within the body, thereby helping to reduce and alleviate flu symptoms more swiftly. Like norepinephrine in our bodies facilitates various processes such as wakefulness and focus, a key enzyme known as polymerase acidic protein (PA) helps facilitate vital functions for influenza viruses. Xofluza acts by blocking this enzyme, thus disrupting viral multiplication. Its mechanism differs from Relenza, which inhibits another enzyme called neuraminidase on the surface of influenza viruses. Although both medications are designed to combat flu, Xofluza has been favored due to its simpler dosing regimen - it requires only one oral dose compared to multiple doses or inhalations required with Relenza treatment.
How effective are both Relenza and Xofluza?
Both zanamivir (Relenza) and baloxavir marboxil (Xofluza) are antiviral drugs that have been approved by the FDA for treating influenza. They were initially approved at different times, with Relenza receiving approval in 1999 and Xofluza in 2018. These medications act on different viral proteins; therefore they may be prescribed under different circumstances.
The effectiveness of these two drugs has been evaluated in multiple clinical trials. Zanamivir, when administered within 48 hours of symptom onset, can significantly reduce the duration of influenza symptoms compared to placebo treatment. Similarly, a study published in 2018 showed that baloxavir marboxil also reduced the duration of flu symptoms when given within the same time frame.
Zanamivir is an inhibitor of neuraminidase - an enzyme produced by the flu virus which allows it to spread from infected cells to healthy ones. Baloxavir marboxil works differently; as a polymerase acidic endonuclease inhibitor, it prevents the replication of flu viruses inside host cells.
While both medications share common side effects such as diarrhea and bronchitis, one notable difference between them is their administration routes: zanamivir is taken through inhalation while baloxavir marboxil is orally administered.
A systematic review conducted in 2006 provided evidence supporting zanamivir's efficacy against influenza A and B viruses along with its safety profile during seasonal epidemics. On another note, a double-blind trial carried out in Japan suggested that single-dose therapy using baloxavire was superior over oseltamivire (another standard antiflu drug), especially among those treated within 24 hours after fever onset due to its potent novel mechanism.
Baloxavire may be considered preferential mainly for patients unable or unwilling to use inhaling devices required for zanamvir’s administration or if there's any history indicating difficulty tolerating neuraminidase inhibitors like oseltamvir or peramiver due to side effects such as nausea/vomiting or psychiatric disturbances respectively.
At what dose is Relenza typically prescribed?
Inhaled dosages of Relenza for the treatment of influenza are 10 mg (two inhalations) twice daily for five days. Children aged seven years and older can also use this dosage. However, Xofluza is administered orally as a single dose dependent on body weight: patients weighing less than 80 kg receive one 40 mg dose while those weighing at least 80 kg receive one 80 mg dose. In children aged between twelve to seventeen, Xofluza can be given if they weigh at least 40 kg. It's important to notify your doctor if there is no improvement in symptoms after using either medication.
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At what dose is Xofluza typically prescribed?
Xofluza treatment is typically initiated as a single oral dose, dependent on the patient's weight. For patients weighing less than 80 kg, a dose of 40 mg is recommended; for those weighing at least 80 kg, an increased dosage of 80 mg is advised. This can be administered with or without food and should be taken as soon as possible after symptom onset, ideally within 48 hours for maximum efficacy. Unlike other antivirals that require multiple doses over several days, Xofluza involves just one convenient and timely dose to combat influenza. If symptoms persist after taking Xofluza, it may be necessary to consult your healthcare provider again.
What are the most common side effects for Relenza?
Common side effects of Relenza may include:
- Bronchitis
- Cough
- Nasal irritation
- Ear, nose, and throat infections
- Sinusitis (inflammation of the sinus cavities in the head)
- Headache
On the other hand, Xofluza can cause:
- Diarrhea
- Bronchitis
- Nausea -High blood pressure -Sinusitis (inflammation of the sinus cavities in the head)
It's important to understand that both drugs are used for similar purposes - to prevent or treat influenza. The choice between them should be made based on your individual health circumstances and ideally under medical supervision.
Are there any potential serious side effects for Relenza?
In rare cases, severe side effects can occur when taking Relenza or Xofluza. These may include:
- Signs of a serious allergic reaction such as difficulty breathing, swelling in your face or throat, hives, and severe skin reactions including fever, sore throat, burning eyes, skin pain with a red or purple rash that spreads and causes blistering and peeling.
- Respiratory complications like bronchospasm characterized by wheezing or trouble breathing particularly if you have an underlying respiratory disease like asthma or COPD.
- Behavioral changes possibly leading to self-harm: some patients (especially children and teenagers) may experience unusually erratic behavior which might lead to confusion, hallucinations; anxiety; agitation; aggression; insomnia etc.
- Cardiovascular issues signified by fast heartbeats/pulse rate fluctuation/heart fluttering/chest discomfort
- Neurological symptoms like seizures accompanied by loss of consciousness for a short period.
If any of these signs are observed after consumption of either drug it is recommended that the medication be discontinued immediately and medical attention sought promptly. Please note this list does not cover all possible side effects.
What are the most common side effects for Xofluza?
The potential side effects of Xofluza, an antiviral medication used for treating the flu, include:
- Diarrhea and stomach pain
- Nausea or vomiting
- Headache
- Bronchitis symptoms: cough, sore throat, stuffy nose
- Dizziness or feeling tired While these are common mild reactions to Xofluza, severe allergic reactions can occur. Symptoms may include rash; fever; burning eyes; skin pain followed by red or purple skin rash that spreads (especially in the face or upper body) causing blistering and peeling. It is essential to seek medical attention immediately if you experience any severe symptoms.
Are there any potential serious side effects for Xofluza?
Xofluza, like any medication, can cause side effects in some people. These could potentially include:
- Signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue or throat
- Sudden dizziness or a light-headed feeling (like you might pass out)
- Common cold symptoms such as stuffy nose, sneezing, sore throat
- Diarrhea or stomach pain
- Abnormal behavior changes
- Hallucinations with severe confusion
If you experience these side effects after taking Xofluza it is imperative to seek immediate medical attention. Also remember that it's crucial to take this medication at the first sign of flu symptoms and within 48 hours from when they started.
Contraindications for Relenza and Xofluza?
Both Relenza and Xofluza, along with most other antiviral medications, may cause some side effects. If you notice serious symptoms like bronchitis or allergic reactions such as a rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, or trouble breathing after administering these drugs, please seek immediate medical attention.
Neither Relenza nor Xofluza can be taken if you are taking certain live vaccines (such as measles, mumps rubella MMR). Always inform your physician about all the medications you take; live vaccines should not be given for at least 48 hours before starting treatment with either drug to prevent interactions. Beyond that period it's also important to wait until two weeks after completing a course of Relenza or Xofluza before receiving any further live vaccinations. This is crucial to ensure proper immune response and vaccine effectiveness.
How much do Relenza and Xofluza cost?
For the brand name versions of these drugs:
- The price for one treatment course (20 mg) of Xofluza averages around $150, which is a single-dose antiviral medication taken within 48 hours of flu symptom onset.
- The price for a full course treatment with Relenza (two inhalations twice daily for five days) averages about $67, working out to approximately $13.40/day.
Thus, if you're considering the total cost per treatment course, then brand-name Relenza appears less expensive than Xofluza. However, it's important to note that this doesn't take into account convenience and adherence issues related to the more complex dosing regimen of Relenza compared to Xofluza’s single dose. Cost should not be your only consideration in determining which drug is right for you.
Currently, there are no generic versions available for either Relenza or Xofluza in the United States; therefore costs will remain relatively high until such alternatives become available.
Popularity of Relenza and Xofluza
Zanamivir, in generic form as well as brand names such as Relenza, is a neuraminidase inhibitor used to treat influenza A and B viruses. It was estimated to have been prescribed to about 1.5 million people in the US during the flu season of 2019-2020. Zanamivir accounted for just over 10% of antiviral prescriptions for influenza in the US. However, it's worth noting that its usage has slightly decreased since 2013 due to the introduction of newer drugs.
Baloxavir marboxil, including brand versions like Xofluza, is a selective inhibitor of influenza cap-dependent endonuclease and was prescribed to approximately 2 million people during the same period. In terms of overall flu antiviral prescriptions within America, baloxavir marboxil makes up roughly 15%. The prevalence of baloxavir marboxil has been increasing significantly ever since its approval by FDA in late 2018 due to its novel mechanism and single-dose regimen which offers convenience over multiple dose regimens like zanamivir.
Conclusion
Both Relenza (zanamivir) and Xofluza (baloxavir marboxil) are antiviral medications used to treat the flu. They have both demonstrated effectiveness in shortening the duration of flu symptoms, based on numerous clinical trials and studies. Their usage may intersect but it is subject to careful consideration by a doctor since they work differently against influenza viruses. Specifically, Relenza works by inhibiting neuraminidase, an enzyme that allows newly formed viruses to leave infected cells; while Xofluza inhibits endonuclease, an enzyme needed for viral replication.
Relenza is typically administered via inhalation using a Diskhaler device twice daily for five days, whereas Xofluza requires only one oral dose regardless of patient weight or age which offers convenience advantage.
Both drugs are available under their generic names as well as brand names though cost can vary depending on insurance coverage and locality.
The side effect profiles between the two drugs differ slightly: common side effects of Relenza include bronchitis, sinusitis, coughing, headache; while those of Xofluza include diarrhea, bronchitis and nausea. For both medications patients should contact health care providers if serious allergic reactions occur or symptoms didn't improve after taking them.