Oseltamivir phosphate, commonly known by its brand name Tamiflu, is an antiviral medication that has been widely used to treat and prevent influenza A and B (flu). It belongs to a class of drugs called neuraminidase inhibitors, which work by blocking the spread of the flu virus in the body. The medication is available in capsule or oral suspension form and is prescribed for individuals aged 2 weeks and older.
The active ingredient in Tamiflu, oseltamivir, is a prodrug that is converted into its active form, oseltamivir carboxylate, in the body. This active metabolite then targets the neuraminidase enzyme on the surface of the influenza virus. By inhibiting this enzyme, oseltamivir prevents the release of new viral particles from infected cells, thereby reducing the severity and duration of the flu.
Oseltamivir phosphate is effective against both seasonal influenza and avian influenza (bird flu) viruses. Its primary uses include:
- Treatment of Influenza: Oseltamivir phosphate is used to treat flu symptoms in individuals who have had flu symptoms for no more than 48 hours. It can help alleviate symptoms such as fever, chills, cough, sore throat, and body aches, and can reduce the duration of these symptoms.
- Prevention of Influenza: The medication can also be used to prevent the flu in individuals who have been exposed to someone with the flu or in situations where exposure is likely, such as during a flu outbreak.
To be most effective, oseltamivir phosphate should be started within 48 hours of the onset of flu symptoms for treatment or within 48 hours of exposure to the flu virus for prevention. The standard treatment course is 5 days for adults and children, although the duration may vary depending on the individual’s condition and response to the medication.
Dosage and Administration: - The dosage of oseltamivir phosphate is based on the patient’s age, weight, and kidney function. - For adults and adolescents 13 years and older, the recommended dosage for treatment is 75 mg twice daily for 5 days. - For children, the dosage is determined by their weight, ranging from 30 mg to 75 mg twice daily. - For prevention, the dosage for adults and adolescents 13 years and older is 75 mg once daily for at least 10 days, and for children, it is similarly based on their weight.
Side Effects: While generally well-tolerated, oseltamivir phosphate can cause side effects, including nausea, vomiting, diarrhea, bronchitis, abdominal pain, and headache. Rare but serious side effects can include allergic reactions and neuropsychiatric events such as delirium and hallucinations, especially in children and adolescents.
Resistance and Limitations: Over the years, there have been concerns about the development of resistance to oseltamivir phosphate among certain strains of the influenza virus. Monitoring for resistance is an ongoing process, and healthcare professionals must stay updated on the effectiveness of oseltamivir against current circulating strains of the flu virus.
In conclusion, oseltamivir phosphate is a valuable medication in the management and prevention of influenza, offering a therapeutic option to reduce the severity and spread of the flu virus. However, its use should be guided by healthcare professionals, considering factors such as the patient’s health status, potential side effects, and the prevalence of resistant viral strains.
What is the primary mechanism of action of oseltamivir phosphate?
+Oseltamivir phosphate works by inhibiting the neuraminidase enzyme on the surface of the influenza virus, preventing the release of new viral particles from infected cells.
What are the common side effects of oseltamivir phosphate?
+Common side effects include nausea, vomiting, diarrhea, bronchitis, abdominal pain, and headache. Serious side effects can include allergic reactions and neuropsychiatric events.
How soon should oseltamivir phosphate be started for the treatment of influenza?
+Oseltamivir phosphate should be started within 48 hours of the onset of flu symptoms to be most effective.
Steps for Taking Oseltamivir Phosphate
- Read the patient information leaflet provided by your pharmacist before you start taking oseltamivir phosphate and each time you get a refill.
- Take oseltamivir phosphate exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
- If you are taking the capsule form, swallow it whole with water. If you are taking the oral suspension, shake the bottle well for about 5 seconds before each use.
- Start taking oseltamivir phosphate as soon as possible within 48 hours of flu symptom onset for treatment or exposure for prevention.
- Complete the full course of treatment or prevention as directed, even if you start feeling better.
