On the global scale, there are a huge number of drugs designed to increase potency, which are widely used by men suffering from erectile dysfunction.
Depending on the underlying nature of the potency problem, various methods of medicinal treatment may be available based on unique drug properties.

Drugs for the treatment of erectile dysfunction can be divided into the following groups:

  • Inhibitors of phosphodiesterase-5 (PDE5)
  • Hormonal preparations
  • Alternative preparations


Medicines belonging to this group block a specific enzyme in the body (i.e., phosphodiesterase type 5), thereby improving blood flow within the penis. Within this group of drugs, there are three pharmacotherapies that can be readily identified. These are Viagra, Levitra, and Cialis. Each medication has both pluses and minuses.


Levitra appeared on the market at a similar time as Cialis in 2003 [1]. This pharmacotherapy demonstrates undeniable advantages over other drugs for the treatment of erectile dysfunction. For example, it is suggested that Levitra has a powerful effect allowing for a quality erection in those men who have benefitted from Viagra or Cialis. Secondly, there are practically no side effects of Levitra. Thirdly, the duration of Levitra is estimated to last up to 12 hours.
Levitra is dispensed in the following doses: 5, 10, or 20 mg tablets. The maximum safe dosage per day is 20 mg. The active ingredient of Levitra is vardenafil hydrochloride trihydrate (vardenafil).

The average price of Levitra from the German company Bayer is $15-16 per 20 mg tablet. Prices for generic Levitra are $2-4 per tablet.


Viagra is the landmark drug in this group of pharmaceuticals. The first sales of this medication began in 1998. However, Viagra has still maintained a leading position in this market.

What is the mechanism of action of Viagra?

An erection that occurs during sexual arousal occurs due to substances that enhance blood circulation within the penis. Due to the blocking of the aforementioned enzyme, perfusion of blood vessels increases leading to an erection.
The active substance contained in Viagra is sildenafil citrate, which is a synthetic substance. The preparation of Viagra in itself is synthetic. This pharmacotherapy should be used 40-60 minutes prior to sexual intercourse. Activation of sildenafil begins roughly 30 min following ingestion with the length of activity lasting about 4 hours.

Among the most common side effects of Viagra noted in the informational pamphlet are nausea, redness of the face, heartburn or headache.

Viagra is typically dispensed in dosages of 25, 50 or 100 mg. For some online pharmacies higher dosages are sold. The maximum dosage recommended according to the instructions is 100 mg. Therefore, it is unsafe to take higher dosages. Specific Viagra dosages should be determined by a doctor based on the severity of erectile dysfunction. Depending on therapeutic progress, the dosage may vary over time.

Prices for brand-name Viagra (i.e., Pfizer) range from $30-35 per 100 mg tablet. Prices for generic Viagra (a copy of the drug) are within the range of $3-4.


The drug called Cialis came to market much later than Viagra (i.e., 2003). However, this drug has quickly taken a commanding place in the market. Consumers have appreciated Cialis because of the duration of effect is much greater than Viagra, reaching upwards of 36 hours. Therefore, Cialis can be taken with considerable time in advance of sexual intercourse, which is convenient.

Cialis also has side effects including nasal congestion, headaches, and dyspepsia.
Cialis is produced in doses of 2.5, 5, or 20 mg. This is because the active substance of Cialis is tadalafil, not sildenafil citrate as in Viagra. The maximum daily dosage should not exceed 20 mg.

Prices for Cialis from the American company Lilly range from $10-12 per 20 mg tablet, which may depend on the dosage and number of tablets in a given package.

Prices for generic Cialis are $2-3 per tablet.