The difference between Polyethylene Glycol Interferon α-2a Injection 135 μg/ 0.5 ml /count and 180 μg/ 0.5 ml /count lies in the fact that the content in the medicine is different. Polyethylene Glycol Interferon α-2a Injection is made by modifying the virus-fighting proteins produced naturally in the human body. It is used in the treatment of hepatitis B and C. The difference between 135 μg/ 0.5 ml/count and 180 μg/ 0.5 ml/count is the amount of the drug. The dosage required for treatment is also different due to the different content. Adverse reactions are headache and muscle pain in most patients, but they are usually mild and treatment is not affected. It is contraindicated in patients with allergies and depression. When using the above medications, patients are advised to follow the doctor’s instructions strictly.