Viagra and Cialis are both drugs used to treat erectile dysfunction (ED) in men.
Guía de Salud Masculina
1. Mechanism of action
1. similarity
- Both belong to phosphodiesterase 5 (PDE5) inhibitors. The physiological mechanism of penile erection involves the release of nitric oxide (NO) in the corpus cavernosum of the penis during sexual stimulation. NO activates guanylate cyclase, resulting in increased levels of cyclic guanosine phosphate (cGMP), which makes the smooth muscle in the corpus cavernosum relax, and blood flows in to cause erection. PDE5 inhibitors can inhibit the degradation of cGMP, thereby enhancing erectile function.
2. differences
onset time
- Viagra is usually taken about 30 minutes to an hour before sexual activity and takes effect relatively quickly.
- Cialis has a relatively long-lasting effect. When taken as needed, it can be taken about 30 minutes before sexual activity. It can also be taken in a small dose once a day. Generally, a stable blood concentration can be achieved after taking it continuously for several days, achieving the effect of sexual activity at any time.
duration of action
- The duration of action of Viagra is approximately 4 - 5 hours.
- Cialis can last for up to 36 hours and is called "weekend pills", which means that for a long time after taking the drug, patients are likely to gain and maintain an erection while sexually stimulated.
2. Precautions for use
1. applicable population
- It is suitable for most patients with erectile dysfunction caused by psychological or organic reasons, but it requires a doctor's evaluation before use to exclude some contraindications, such as severe cardiovascular diseases (especially those taking nitrates, because combination may cause severe hypotension), hypotension, serious impairment of liver and kidney function, etc.
2. adverse reactions
common reactions
- Both can cause adverse reactions such as headaches, facial flushing, indigestion, and nasal congestion. These symptoms are usually mild to moderate and generally temporary.
special reaction
- Cialis may have a slightly higher incidence of muscle pain than Viagra.
These drugs must be used under the guidance of a doctor and cannot be purchased and abused by yourself to ensure safety and effectiveness.