How many days of taking oseltamivir are needed to reduce fever caused by influenza B?

After taking oseltamivir, patients with type B influenza typically experience fever reduction within 2–3 days. Most patients will gradually see their body temperature decrease and return to normal. The medication should be taken according to the prescribed course under a doctor's guidance. If high fever persists beyond five days of treatment or symptoms such as difficulty breathing occur, prompt medical attention is recommended.

Oseltamivir works by inhibiting the neuraminidase activity of the type B influenza virus, preventing viral replication and spread in the body, thereby alleviating symptoms and shortening the duration of illness. Starting the medication within 48 hours of symptom onset allows for faster antiviral effects, quicker normalization of body temperature, and reduced duration of high fever.

The time required for fever resolution may vary depending on the patient's age, physical condition, and severity of illness. Younger individuals with good physical health and milder symptoms may defervesce within 1–2 days of treatment. Older patients, those with weakened immunity, or individuals with more severe symptoms may take longer to reduce fever, although it generally does not exceed five days. It is important to complete the full course of treatment as directed by a physician.

During oseltamivir treatment, patients should maintain adequate fluid intake to promote metabolism and sweating, which aids in fever reduction. A light and easily digestible diet is recommended, avoiding spicy or irritating foods. Sufficient rest should be ensured, and overexertion should be avoided to support recovery.