What are the side effects of Oseltamivir?

Generally, oseltamivir is available in capsule and granule formulations. Side effects of oseltamivir include gastrointestinal discomfort, headache and dizziness, allergic reactions, abnormal liver function, and fatigue. It is recommended to take this medication according to medical advice. Detailed explanations are as follows:

1. Gastrointestinal Discomfort

The pharmaceutical components of oseltamivir may directly irritate the gastrointestinal mucosa and interfere with gastrointestinal neural reflexes, causing gastrointestinal smooth muscle spasms, thereby inducing nausea and vomiting. At the same time, the drug affects the normal secretion of digestive fluids and peristaltic rhythm in the gastrointestinal tract, leading to abnormal digestion and transmission of food, causing abdominal pain and diarrhea, which disrupts normal digestion and eating.

2. Headache and Dizziness

Oseltamivir and its metabolites may affect the central nervous system by passing through the blood-brain barrier. They can interfere with the normal regulatory mechanisms of cerebral blood vessels and alter the vasodilation and vasoconstriction states of cerebral vessels, leading to insufficient cerebral blood supply or abnormal hemodynamics, thus causing headache and dizziness, making the head feel heavy.

3. Allergic Reaction

An individual's immune system may recognize oseltamivir as a foreign antigen and initiate an immune response. The immune system produces specific antibodies, and upon re-exposure to oseltamivir, antigen-antibody complexes form, activating a series of immune reactions and releasing inflammatory mediators such as histamine. Histamine causes skin vasodilation and increased permeability, resulting in rashes, skin itching, and red papular eruptions.

4. Abnormal Liver Function

The drug and its metabolites may directly damage hepatocytes, interfering with normal metabolic pathways within liver cells, such as affecting redox reactions and detoxification processes in the liver. When liver cells are damaged, enzymes such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST) inside the cells are released into the bloodstream, leading to elevated liver function indicators and affecting the liver's metabolic and detoxification functions.

5. Fatigue and Weakness

The drug may interfere with mitochondrial function. Mitochondria are important sites for cellular energy production; when their function is impaired, cellular energy generation decreases. During the body's response to the drug and viral infection, the immune system is activated, consuming significant amounts of energy. Under the combined effects, patients often feel significant fatigue and weakness, experience energy depletion, reduced exercise tolerance, and impaired daily physical activities and work capacity.

In daily life, it is essential to strictly follow medical instructions when taking medication. If discomfort occurs during medication, promptly contact a physician to adjust the treatment plan as necessary.