1, cannot be used on the same day with nitrates, otherwise blood pressure drops sharply and there is a risk of sudden death. 2.It is contraindicated for hypotension, refractory arrhythmia, refractory hypertension, stroke in the last 6 months, and taking alpha-blockers. 3. If you have any of the following diseases or conditions, be sure to inform your doctor before deciding whether you can use the medication. These include mainly heart problems, stroke, high or low blood pressure, retinitis pigmentosa, kidney or liver disease, blood disorders (e.g. sickle cell anemia, leukemia), allergy to components of Viagra-like drugs, peptic ulcer or other bleeding conditions. 4, it should also be noted that it must be taken on an empty stomach or 2 hours after a meal, eating high-fat, greasy food will significantly delay the onset of action time and efficacy. 5, before and after taking the drug can not drink alcohol, and should not take a hot bath. 6, 1 hour after taking the drug, in the presence of sexual stimulation effect, the effect time up to 24 hours or more. 7, it is recommended that the young and strong people first 1/2 capsule, if the effect is good, the second 1/3 or 1/4 capsule. A large glass of warm water to take.