Viagra generally refers to sildenafil, generally as long as you follow the doctor’s instructions to pay attention to the dosage, one or two sildenafil a week is not harmful, but if overdose may lead to headache, dizziness, dizziness, blurred vision, flushing and other symptoms. Sildenafil is a drug for erectile dysfunction, which belongs to the class of PDE5 inhibitors, and the drug is not prescribed to be taken several times a week, and its maximum frequency of dosing does not exceed 24 hours. And the frequency of 1~2 times a week is not too high. Therefore, as long as the dosage is in accordance with the doctor’s instructions, generally does not cause any harm. However, as the drug can cause headache, dizziness, dizziness, blurred vision, flushing and other adverse reactions. Therefore, if the drug is used 1 to 2 times a week, but each time the dosage is more than the doctor’s prescribed amount, it may lead to a higher incidence of these adverse reactions. The drug should be used under the supervision of a doctor, and should not be purchased and taken blindly to avoid the effects on the body. It should also be noted that sildenafil is not allowed to be used in combination with nitrate drugs, and it is contraindicated for women, people who are allergic to the product, children, and people who are not suitable for sexual intercourse in recent cardiovascular conditions.