Took sildenafil the first few times there is a reaction, no reaction in the later period, there are many factors affecting the effect, may be related to the habit of taking the drug, the state of the body and other reasons, in addition, there may be a certain degree of resistance to the drug, take the dose is not enough. Sildenafil after taking the drug is not obvious effect affects, there are many factors, if the sexual stimulation is not enough, it will be very obvious to affect the effectiveness of the drug. If the diet is more fat, it will affect the absorption of the drug. If the recent psychological pressure is relatively large, the couple’s relationship is not harmonious, or the body is more tired, then the effect of taking the drug is also not obvious. If the patient has developed drug resistance to the drug, then it is possible to take the dose is not enough, the effect can not be achieved, you can increase the dose accordingly. If the dietary habits, as well as psychological state and physical state adjustment, if there is still no significant improvement, you can increase the dose of the drug, if sildenafil is still no obvious effect, we should go to the hospital to check to exclude organic lesions, and then choose the appropriate treatment program.