A box costs more than 400 yuan, and one dose lasts for 5 days? The new "magic flu drug" Mabaloxavir is popular, and doctors warn

The proportion of influenza A has just dropped, and the proportion of influenza B has risen sharply. According to the National Center for Disease Control and Prevention's influenza weekly report for the 52nd week of 2023, influenza B accounts for 35.5% of the influenza monitoring data in the north and south. Since January 2024, there have been reports of a sharp increase in the number of patients infected with influenza B in outpatient clinics in many places.

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The sales of drugs corresponding to the flu wave are also worthy of attention. In particular, the new anti-influenza drug Mabaloxavir has a medical insurance price of about 222 yuan, but due to the hot sales at the retail end, the selling price on some platforms has even reached 400 yuan, and there are cases where the drug is not available in local pharmacies. Is this drug really a "special flu drug"? What are the precautions for taking flu drugs? Today's popular science article will talk to you about this topic.

Mabaloxavir

Is it really a “magic drug” against influenza?

Let me first state the conclusion:

Mabaloxavir has many advantages and is effective against both influenza A and influenza B, but it is an exaggeration to call it a "miracle drug".

Mabaloxavir is an anti-influenza drug launched in China in 2021. In particular, it has recently been approved as a suspension formulation for the treatment of influenza in children aged 5 to 12 years. Compared with the anti-influenza oseltamivir, in addition to the different mechanism of action, the main advantage of mabaloxavir lies in the long-acting effect of the drug. This is a drug that can be taken once after being infected with influenza and can take effect within 5 days. It can be said to be excellent in improving the convenience and compliance of medication.

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In terms of drug action mechanism, Mabaloxavir belongs to the class of viral RNA polymerase inhibitors. It is a prodrug that inhibits influenza virus replication by inhibiting the activity of influenza virus polymerase endonuclease. This drug is effective against both influenza A and influenza B viruses.

Compared with oseltamivir, although the two have different targets, their ultimate effect is to inhibit the viral replication process rather than to kill or eliminate the influenza virus. Therefore, in terms of anti-influenza, timely use of mabaloxavir in the early stages of infection can indeed relieve symptoms and shorten the course of the disease. However, if it is called a "miracle drug", it is an exaggeration. Ultimately, it is our body's immune system that truly eliminates the influenza virus in the body.

In addition, when using mabaloxavir, some contraindications and precautions should also be noted. For example, when taking the medicine, it is necessary to avoid taking it with beverages containing high-valent cations such as calcium and iron. At the same time, it is also necessary to avoid taking it with drugs containing high-valent cations.

Is there a big difference between influenza A and influenza B?

The recent increase in influenza B infection rates has also attracted the attention of many friends. Are there big differences between influenza A and influenza B? According to the influenza monitoring data this winter, the influenza A H3N2 strain was the main prevalent strain in the early stage, while the influenza B Victoria strain has increased significantly recently.

There are some differences between the two strains in terms of virus morphology, but there are no significant differences in symptoms after infection. No matter which strain you are infected with, you may experience respiratory symptoms such as high fever, body aches, fatigue, sore throat, cough, shortness of breath, etc. It is difficult to tell whether it is influenza A or influenza B infection from the symptoms, and the severity of the symptoms after infection is mainly related to individual differences.

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In terms of drug treatment, whether it is influenza A or influenza B, the antiviral drugs we are familiar with, oseltamivir and mabaloxavir, can effectively inhibit viral replication and play a certain role in alleviating the disease. However, in terms of combating influenza B, clinical data show that compared with oseltamivir, mabaloxavir has certain advantages in relieving symptoms and shortening the course of the disease, and the time for viral detoxification to stop is shortened by 48 hours.

Flu medication

Please note these 3 points

Faced with the still high tide of influenza, whether it is influenza A or influenza B, once infected, in many cases, medication is still inevitable to relieve symptoms or reduce the risk of developing severe infection. Taking advantage of this topic today, I will introduce three key points about medication after influenza infection.

1. Antiviral drugs, use as early as possible

As mentioned above, although antiviral drugs such as oseltamivir and mabaloxavir cannot kill viruses, they can effectively relieve symptoms and shorten the course of influenza A and B infections. However, when using these drugs, we must adhere to the principle of "as early as possible". If they are used within 48 hours after the onset of symptoms of viral infection, the drugs will be effective in the early stages of the virus's replication and reproduction after it begins to invade the body's cells, and will have a better antiviral effect. If the initial stage of infection has passed, the effectiveness of the drugs will be greatly reduced if they are used later.

There is a contradiction here. Many times, the symptoms of respiratory pathogen infection are similar, including mycoplasma, influenza virus, respiratory syncytial virus, new coronavirus, etc., which may cause related symptoms of respiratory infection. However, whether it is an influenza virus infection cannot usually be directly judged by symptoms, and timely testing is required to distinguish it clearly.

Therefore, especially for the elderly and the weak who are at high risk of severe illness, they should seek medical attention in time when relevant symptoms appear. If it is found to be influenza infection, it is still necessary to give antiviral drugs in time to reduce the risk of severe infection.

2. Do not take medications that relieve symptoms

In addition to antiviral drugs, when symptoms such as fever and cough occur, it is often necessary to take related drugs to relieve them. Antipyretics such as acetaminophen and ibuprofen, expectorants such as acetylcysteine ​​granules and ambroxol, and cough suppressants such as dextromethorphan are all commonly used drugs.

However, it should be noted that many compound cold medicines and cough medicines contain the various drug ingredients mentioned above. When using single medicines to relieve related symptoms, you must pay attention to whether the combined compound medicines contain similar ingredients. If there is a risk of drug overdose due to repeated use, it will really not be worth it.

3. To prevent influenza, do not use antiviral drugs indiscriminately

Many people always want to prevent influenza through drugs, whether it is oseltamivir or mabaloxavir. Although from the mechanism of action, taking drugs may reduce the chance of infection, this effect is only effective during the medication period. After stopping the medication, the preventive effect of the drug will disappear, and the preventive effect itself is extremely limited. Research data shows that in terms of preventing mutual infection between family members (close contact), the prevention efficiency of mabaloxavir is 24.1%, while the prevention efficiency of oseltamivir is 17.9%.

Therefore, it is impossible to expect to completely prevent influenza through drugs. For people at high risk of severe illness and those with clear risk of close contact, they can take antiviral drugs for a period of time to prevent influenza infection. However, for people with normal immunity, it is completely unnecessary to take antiviral drugs to prevent influenza.

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If you want to prevent influenza, you might as well develop good hygiene habits, keep indoor air circulating, wash your hands frequently, wear masks in crowded places, and get vaccinated. These are important ways to effectively reduce the risk of influenza virus infection. Especially when the flu season is approaching, everyone must get the flu vaccine in time, especially families with elderly and young children. All family members who meet the vaccination conditions are best to get the flu vaccine.

This article is a work of Science Popularization China-Starry Sky Project

Produced by: Science Popularization Department of China Association for Science and Technology

Producer: China Science and Technology Press Co., Ltd., Beijing Zhongke Xinghe Culture Media Co., Ltd.

Author: Li Jin, deputy director and pharmacist, deputy leader of the Youth Studies Group of the Medical Committee of the China Science Writers Association

Review丨Liu Guiyang, Chief Pharmacist, Fourth Medical Center, PLA General Hospital