Viagra is the trade name and generic name of sildenafil citrate tablets, which is a drug used to treat erectile dysfunction. The effect of the drug can be maintained for about 4 hours after taking it, but it is uncertain how many times you can have sex, and it is recommended that you have sex once after taking it. Theoretically, half an hour after taking Sildenafil citrate tablets, the penis will become erect under sexual stimulation, and the effect of the drug lasts for about 4 hours. It is possible to have sex several times during the validity period of the drug. However, each person’s physical condition is different, and the time it takes to become erect again after ejaculation is different, and all these factors will affect the number of times you can have sex during the drug’s validity period. It should be noted that taking sildenafil may cause adverse reactions such as fainting, tachycardia and palpitations. Too frequent sexual intercourse is likely to lead to physical exhaustion, weakness and other discomforts. Therefore, it is recommended to have sex once after taking the drug is more prudent.