Special attention is paid by the so-called erection stimulants. This is a group of drugs that allow you to:

improve potency and strengthen erection;
increase sexual desire;
improve the quality of seminal fluid;
increase the duration of sexual intercourse.

There are a lot of similar pharmaceutical products, these are both licensed medicines and various biologically active additives. However, conditionally in medicine they are divided into 2 groups based on the composition: based on synthetic derivatives and natural, natural components.
The most popular and effective drugs are those that include type 5 phosphodiesterase inhibitors: sildenafil, vardenafil, tadalafil. These substances contribute to the expansion of the cavernous bodies of the penis and increase blood flow to the small pelvis, which as a result allows you to fill the penis with blood more and block its outflow. The most famous medication of this group is the notorious Viagra, by analogy of which hundreds of analogues and generics have been created.
All of them have been successfully used by doctors to combat erectile dysfunction, however, they have their own characteristics and a number of side effects, contraindications. So, no similar drug will act without prior sexual stimulation, i.e. if the man is not aroused, the pill will not have the desired effect and chemical processes will not start. There is a plus to this – the patient is insured against spontaneous erection. It is also forbidden to use PDE-5 inhibitors for people with certain cardiovascular diseases, pathologies in the structure of the organs of the reproductive system.
According to the type of action, stimulants of erection are also divided into 2 types:

 long-term use drugs having a cumulative effect, manifested after some time from the start of administration and lasting after the end of treatment;
drugs that have an almost instant effect (within 15-60 minutes after ingestion), disappearing after a few hours.