Caverta, like its brand Viagra contains Sildenafil citrate as the active ingredient. It gets absorbed in the body quickly after consumption and enters the bloodstream where it blocks the actions of the key enzyme phosphodiesterase type 5, also called as PDE-5. Due to this there is an instant upsurge in the concentration of nitric oxide (NO) and the enzyme guanylyl cyclase. The enzyme guanylyl cyclase then increase the biosynthesis of cyclic GMP which is a potent vasodilator and widens the blood vessels in the body as well as in the penile region. The enzyme cGMP also has another function of relaxing the penile smooth muscles. Hence, together, both these actions lead to enhancement in the blood circulation to the penis and blood to be retained for prolonged period of time so as to achieve a long lasting and firm erection. Action of Caverta lasts for almost 4-5 hours after consumption and hence, this is helpful in indulging into long-lasting sexual activity.