Oseltamivir, are you using it correctly?

After entering the peak season of influenza, people around me are constantly "infected", with fever, cough, and fatigue. Among the "army of drugs" to deal with influenza, oseltamivir phosphate has attracted much attention and even become a "magic drug" in people's mouths. But do you really understand it? When should it be used, what dosage should be used, and what precautions should be taken?

Don’t worry, let us learn about the rational use of oseltamivir phosphate to protect the health of ourselves and our families.

1. Mechanism of action of oseltamivir: // How does oseltamivir phosphate work?

Oseltamivir phosphate is a selective neuraminidase inhibitor that can bind to the neuraminidase on the surface of influenza viruses, inhibiting the enzyme's ability to cut off sialic acid on the surface of infected cells, thereby preventing the release of newly generated influenza virus particles from infected cells and inhibiting the replication and spread of influenza viruses.

2. Indications [1]: //When is oseltamivir phosphate used?

(1) For the treatment of influenza A and B in adults and children aged 1 year and above; patients should use it within 48 hours of the first onset of symptoms.

(2) For the prevention of influenza A and B in adults and adolescents aged 13 years and above.

3. Dosage form: //What dosage forms of oseltamivir phosphate are available and for which groups of people is it suitable?

The dosage forms of oseltamivir phosphate mainly include capsules, granules and dry suspensions:

Ø Capsules are suitable for adults or older teenagers;

Ø Granules are suitable for children or infants, and the dosage can be adjusted according to the child's weight and age;

Ø Dry suspensions are also suitable for children or infants. When using, they must be prepared into solutions according to the method recommended in the instructions. It is recommended to be used immediately after preparation and not to be stored for a long time.

4. Dosage and Administration [2, 3]: // How much oseltamivir should I take?

(1) Oseltamivir phosphate capsules (granules) can be taken with or without food . However, for some patients, taking the drug with food can improve drug tolerance.

(2) When used for the treatment of influenza, patients should use it within 48 hours of the first onset of symptoms (ideally within 36 hours); the course of treatment is 5 days, which can be extended appropriately for severe patients.

(3) For the prevention of influenza after close contact with influenza patients, the recommended oral dose is 75 mg once a day for at least 10 days, and the medication should be started within 2 days after close contact. The recommended dose for the prevention of influenza during the influenza season is 75 mg once a day. When using, be sure to follow the doctor's instructions.

5. Use in special populations: // How should special populations use oseltamivir?

(1) For elderly patients and patients with mild to moderate hepatic impairment: no dosage adjustment is required.

(2) For patients with renal insufficiency: Consult a professional doctor before use and reduce the dosage according to changes in creatinine clearance and condition.

(3) For pregnant and breastfeeding women: Oseltamivir is classified as Class C for pregnancy and may be harmful, and is classified as Class L2 for breastfeeding and is relatively safe. The drug should be used with caution. Before use, the pros and cons should be weighed and the doctor's instructions should be followed.

6.What are the common adverse reactions of oseltamivir and how to deal with them?

Common adverse reactions to oseltamivir include nausea, vomiting, and headache, which generally disappear after stopping the medication. If stomach discomfort occurs after taking the medication, oseltamivir can be taken with food. If vomiting occurs after taking oseltamivir, it is necessary to determine whether to take another dose based on the time of vomiting.

7. Precautions for use: //What are the precautions for using oseltamivir?

(1) Oseltamivir only has an inhibitory effect on influenza viruses and can only be used to prevent or treat influenza. It is ineffective against colds caused by other viruses such as coronaviruses and adenoviruses, and against bacterial infections complicated by influenza. Therefore, before taking the drug, you should first identify whether it is influenza to avoid drug abuse.

(2) Oseltamivir cannot replace influenza vaccine, which remains the best choice for preventing influenza.

(3) Oseltamivir needs to be used for a full course of treatment. Even if the condition improves after taking the medicine, it is not recommended to stop taking the medicine on your own.

(4) If you miss a dose of oseltamivir, please make up for it as soon as possible. However, if the next dose is less than 2 hours away, you do not need to make up for it. Just take the next dose as normal. Do not stack two doses!

(5) Oseltamivir does not have antipyretic or antitussive effects. When influenza symptoms appear, symptomatic antipyretics, expectorants, and antitussives are required.

(6) If you are intolerant to fructose, please avoid using the dry suspension.

In addition to oseltamivir, what other drugs can be used to treat influenza?

Note: The above drugs are all prescription drugs and must be used under the guidance of a physician.

Pharmacist reminder:

Oseltamivir is not a "magic weapon". Please follow your doctor's advice when taking it correctly.

The scope of application should be clearly identified so that you can protect yourself when influenza strikes.

References:

[1] Oseltamivir Phosphate Capsules (Tamiflu) Drug Instructions

[2] Expert consensus group on antiviral treatment of influenza in adults. Expert consensus group on antiviral treatment of influenza in adults. Chinese Journal of Infectious Diseases, 2022, 40(11):641-655.

[3] Pediatric Infection Group of the Infectious Diseases Branch of the Chinese Medical Association, Infection Group of the Pediatric Committee of the Capacity Building and Continuing Education of the National Health Commission, Methodology Committee of the Chinese Clinical Practice Guidelines Alliance. Practical Guidelines for the Prevention of Influenza Vaccines and the Use of Antiviral Drugs in Children (2024 Edition). Chinese Medical Journal, 2024, 104(40):3705-3725.

[4] Mabaloxavir Tablets (Sufuda) Drug Instructions

[5] Zanamivir Inhalation Powder (Elavird) Instructions

[6] Peramivir Sodium Chloride Injection (Liwei) Instructions