Oseltamivir has become a hot search keyword, are you going to start stockpiling drugs again? Read the flu "miracle medicine" in one article

True Points:

1. Oseltamivir (Tamiflu) is currently the preferred choice for influenza treatment. In addition, although oseltamivir also has the effect of preventing influenza, it is not recommended to use oseltamivir to prevent influenza except in a few special cases.

2. After the onset of influenza, early administration of oseltamivir antiviral therapy, especially antiviral therapy within 48 hours, has the greatest clinical benefit. For adults and children with moderate to severe disease or progressive disease, oseltamivir remains beneficial after 48 hours.

3. Pregnant women and lactating women can use oseltamivir. According to the standards of the US FDA, it is safe for babies older than 14 days to use oseltamivir under normal dosage.

4. The recommended course of oral oseltamivir is 5 days, and the therapeutic dose for adults is 75mg/time, twice a day for 5 days (the text has a detailed oseltamivir dosage table for adults and children).

5. But remember: oseltamivir has an effective ≠ needs to be used, and in 2017, the World Health Organization adjusted oseltamivir from a "core drug" in the list of essential drugs to a "complementary drug", which shows that oseltamivir is not what we think of as a "perfect miracle drug". During the influenza epidemic, whether we need to use oseltamivir depends more on their symptoms, and whether they are exposed to high-risk people, and we must not use it blindly. If oseltamivir is not justified, the most effective way to prevent influenza is vaccination, as well as necessary hand hygiene and avoidance of human contact.

Verifier: Zhao Yu | Master of Pharmacology

Recently, primary and secondary school students in Beijing, Shanghai and other places have developed fever symptoms, some schools have been closed due to influenza A, oseltamivir has received widespread attention, and some pharmacies have even run out of stock. Is oseltamivir considered a "miracle drug" for influenza? What are the requirements for taking oseltamivir? Does oseltamivir prevent the flu?

First, ostovir is the first choice for current anti-influenza therapy

1. Does oseltamivir have any therapeutic effect?

Useful. Clinical trials and observational data suggest that early antiviral therapy shortens the duration of fever and illness symptoms, and reduces the risk of complications of some influenza (e.g., otitis media in young children, pneumonia, and respiratory failure). In hospitalized children, the clinical benefit is greatest when given early antiviral therapy, especially within 48 hours of influenza onset.

2. When is oseltamivir used?

Whether international or domestic, the attitude towards oseltamivir antiviral therapy is: preferred!

The earlier antiviral therapy is used during the progression of the disease, the greater the clinical benefit. So there are symptoms:

(1) Do not wait for laboratory test results can be used.

(2) A negative rapid diagnostic test result does not exclude influenza, and even if laboratory confirmation is to be made, antiviral therapy should not be delayed.

(3) Treatment should be started immediately, regardless of whether the patient has received seasonal influenza vaccination.

3. Is it useful for more than 48 hours?

Useful. For adults and children with moderate to severe disease or worsening symptoms, oseltamivir remains beneficial after 48 hours.

However, for patients who are not severe and have no other high-risk factors, if their symptoms are mild, the fever is not high, and there is no difficulty breathing, they can actually do not need to go to the hospital, and they do not necessarily have to undergo antiviral therapy. Isolation at home and a good rest is the best way to deal with it.

4. Who is oseltamivir suitable for?

Each institution has a slightly different statement, but what is almost certain is that oseltamivir is safe for the treatment of individuals older than 1 year.

Second, oseltamivir is used for influenza prevention has prerequisites

1. Does oseltamivir have a preventive effect?

Yes. Oseltamivir has been shown to have a preventive effect, with oseltamivir reducing the risk of influenza by 70 to 90 percent [1].

Nevertheless, it is important to know that oseltamivir reduces but does not eliminate the risk of influenza, and that susceptibility to influenza may be restored once antiviral drugs are stopped. It is not comparable to vaccines, and blind use of oseltamivir will also increase the incidence of drug resistance in the population.

2. Which is the strongest preventive effect of oseltamivir and influenza vaccine?

Vaccination remains the mainstay of prevention of influenza, and oseltamivir is a useful complement to influenza vaccine. Of course, influenza vaccination does not exclude the possibility of influenza virus infection in patients with clinical symptoms consistent with influenza.

3. Who needs oseltamivir for prevention?

The US CDC does not recommend widespread or routine use of antivirals for chemoprophylaxis unless it is part of a variety of interventions to control influenza outbreaks. Chemoprophylaxis for influenza may be considered in certain circumstances, such as:

Within two weeks after receiving the influenza vaccine, people at high risk of influenza complications with a history of exposure to influenza patients. High-risk groups include: children under 2 years of age; Adults over 65 years of age and the elderly; patients with chronic lung diseases (including asthma), cardiovascular diseases (except for hypertension itself), diseases of the kidneys, liver, blood (including sickle cell disease) and metabolic disorders (including diabetes mellitus); immunosuppression, including immunosuppression caused by drugs or HIV infection; pregnant or postpartum (within 2 weeks after delivery); people who are extremely obese (i.e. have a BMI equal to or greater than 40); Patients in nursing homes and other long-term nursing facilities due to chronic diseases;

Those who have contraindications to influenza vaccination and cannot receive influenza vaccine, and people at high risk of influenza complications with a history of exposure to influenza patients;

People at high risk of influenza complications with a history of exposure to influenza who have severe immunodeficiency or other people who may not respond to influenza vaccines, such as patients who are receiving immunosuppressive therapy.

If more than 48 hours have passed since the first exposure to influenza, oseltamivir for antiviral chemoprophylaxis is generally not recommended, and there is no need to worry about those who have not been exposed to influenza.

3. How to take oseltamivir correctly?

1. What is the dosage and time to use?

The recommended course of oral oseltamivir is 5 days. For patients who remain severely ill after 5 days of treatment, an extension of the daily dose (oral oseltamivir) may be considered.

For effective chemoprevention, antiviral drugs must be taken daily for the period of possible exposure to a patient with influenza and for 7 days after the last known exposure. For people who undergo antiviral chemoprophylaxis after receiving an inactivated influenza vaccine, the recommended time is before immunization develops after vaccination (depending on age and vaccination history, antibody production after vaccination takes about two weeks for adults and longer for children).

The above recommended dosing regimen is not indicated for preterm infants, who may have slower clearance of oseltamivir due to immature renal function; The use of the recommended doses for term infants may result in high drug concentrations in preterm infants younger than 1 year of age.

2. How to avoid gastrointestinal reactions?

Common adverse effects of oral oseltamivir include gastrointestinal symptoms such as nausea and vomiting, which can be alleviated by taking it with food.

3. How to feed children medicine smoothly?

At present, oseltamivir in China is only available in granules and capsules. When giving oseltamivir to younger children, especially infants younger than 1 year of age, try to choose oseltamivir granules. If granules are not available, oseltamivir capsules can be opened and the drug inside can be mixed with a sweet liquid (e.g., chocolate syrup, corn syrup, etc.).

Since the drug content in capsules is larger than that in granules, it is necessary to formulate 75mg of oseltamivir in capsules into an oral suspension under the guidance of a doctor or pharmacist, and then take the corresponding volume of medicine to give to the baby as needed.

4. Can oseltamivir be taken with other drugs?

During the flu, fever, sore throat, cough and other symptoms are often accompanied by it, in addition to oseltamivir, you may also need to take antipyretics (ibuprofen, acetaminophen), antihistamines (cetirizine), cough medicine (dextromethorphan). These drugs do not interact with oseltamivir and can be taken together.

4. How do special people use oseltamivir?

1. Can pregnant women use it?

OK. The way of use is the same as that of ordinary adults, many studies have shown that neuraminidase inhibitors are safer for pregnant women, and influenza viruses may have greater effects on pregnant women and fetuses during influenza than oseltamivir itself, so it is recommended to use oseltamivir early treatment for influenza during pregnancy.

2. Can children use it?

OK. According to the standards of the US FDA, it is safe for babies older than 14 days to use oseltamivir under normal dosage. However, it should be noted that routine prophylactic oseltamivir is not recommended for infants younger than 3 months of age, except in special circumstances.

3. Can it be used during lactation?

OK. The amount of oseltamivir secreted in milk is very low, even if it is ingested by children, the dosage of oseltamivir for children's flu is very safe, so it can be taken during lactation.

4. Can patients with renal dysfunction and dialysis be used?

OK. For patients with creatinine clearance between 10 ~ 60 mL/min, patients with end-stage renal disease receiving hemodialysis or continuous peritoneal dialysis and receiving oseltamivir therapy or chemoprophylaxis influenza, attention should be paid to adjusting the dose of oseltamivir.

Finally, regarding oseltamivir, we can think that it has preventive and therapeutic effects. ≠In 2017, the World Health Organization adjusted oseltamivir from a "core drug" in the list of essential drugs to a "complementary drug", which shows that oseltamivir is not what we think is a "perfect miracle drug".

During the influenza epidemic, whether we need to use oseltamivir depends more on their symptoms, and whether they are exposed to high-risk people, and we must not use it blindly. If oseltamivir is not justified, the most effective way to prevent influenza is vaccination, as well as necessary hand hygiene and avoidance of human contact. It doesn't matter if you didn't understand it before, it's still time to make up for it now.

This article was edited by Marthaywang

Copyright statement: This article is an exclusive manuscript of Tencent, and media reproduction is prohibited without authorization. Individuals are welcome to forward to Moments.

Resources:

1、Welliver R, Monto AS, Carewicz O，et al. Effectiveness of oseltamivir in preventing influenza in household contacts: a randomized controlled trial. JAMA. 2001 Feb 14;285(6):748-54.

2、Whitley RJ. The role of oseltamivir in the treatment and prevention of influenza in children. Expert Opin Drug Metab Toxicol. 2007 Oct;3(5):755-67.

3、https://www.cdc.gov/flu/professionals/antivirals/summary-clinicians.htm

4、Uptodate:Antiviral drug resistance among seasonal influenza viruses