Opexa medicine, or bilastine as an active ingredient, is an antihistamine medication used to treat the symptoms of allergic rhinitis (hay fever) and urticaria (hives). It works by blocking the action of histamine, a substance released by the body during an allergic reaction that causes inflammation and other symptoms such as sneezing, runny nose, itching, and skin rash.

Bilastine is a second-generation antihistamine that is designed to be non-sedating, meaning it is less likely to cause drowsiness compared to other antihistamines. It is available in tablet form and is usually taken once daily, with or without food. The recommended dosage and duration of treatment may vary depending on the severity of symptoms and the patient's age and medical history.

Opexa 20 mg pills has been shown to be effective in treating the symptoms of allergic rhinitis and urticaria in adults and children over 12 years old. Common side effects of bilastine may include headache, dizziness, dry mouth, nausea, and fatigue. In rare cases, more serious side effects such as allergic reactions or liver problems may occur. It is important to consult a healthcare professional if any side effects occur or if symptoms do not improve after treatment.