Currently, there are four drugs approved by the Food and Drug Administration that can be used to treat erectile dysfunction: Viagra, Levitra, Cialis, and Staxyn. These drugs, known as PDE-5 inhibitors, will enhance performance but will not increase libido. A PDE-5 inhibitor is a chemical that boosts the enzyme that relaxes the smooth muscle cells inside the penis. When combined with sexual excitement, the drug enables the arteries in the penis to widen and the spaces in the erectile chambers to fill with blood. As the veins in the penis expand, they trap blood in the penis for a prolonged period of time.
Multiple clinical trials show that this chain of events creates an excellent erection nearly 80 percent of the time. These drugs seem to be remarkably effective in patients who have a biological reason for their impotence. However, they do not seem to have much impact on men who are getting adequate erections, that is, men who use them as performance-enhancing drugs.
Although all four medications are in the same class of drugs and have the same mechanism of action, they each have slightly different chemical structures and therefore act in slightly different ways.
The first “kid” on the block was Viagra. The usual dose is 50-100 mg. Viagra should be taken one hour prior to sexual activity. One must be sexually stimulated in order for the drug to be effective. So if a man takes the drug and merely looks at the ceiling, nothing will happen! In most cases, Viagra will create an erection firm enough for penetration, and the erection will usually last until orgasm is reached. There is a window of opportunity of up to six hours. Viagra is poorly absorbed on a full stomach, particularly after a fatty meal (and we are talking about a big steak here), so it is best taken before a meal or on a relatively empty stomach.
Levitra is very similar in chemical structure and action to Viagra. The usual dose of Levitra is 10-20 mg. It, too, must be taken about one hour before sexual stimulation. Levitra can be absorbed into the bloodstream, even on a full stomach, and many patients like this feature.
Cialis, which has a standard dose of 10-20 mg, has a much longer chemical half-life and can be effective up to 18 hours after first ingesting the pill. That is not to say that the erection will last 18 hours, but if one is stimulated within the 18-hour window of opportunity, Cialis will usually work very well. Cialis seems to be preferred by the somewhat younger patient with a more active sex life and has been described as the drug for the “weekend warrior.” Cialis also comes in a daily dosage, which is 5 mg. There is no theoretical downside to taking the daily dose if one’s sexual activity warrants it, and many physicians feel there is a beneficial value because it increases coronary artery circulation.
The newest drug on the block is Staxyn. This drug is similar in structure to Levitra. The standard dosage is 10 mg. What makes Staxyn unique is that the tablet is placed on the tongue and is rapidly absorbed orally into the bloodstream. Staxyn has a more rapid onset and a window of opportunity of six or more hours.
It is important that men and women understand that these pills are not aphrodisiacs. They are not sexual cure-alls. They will not work in the absence of desire. Remember that 99 percent of almost all aspects of sexuality (attraction, desire, arousal, and orgasm) reside between the ears. When the brain is stimulated by sexual fantasies or by touch, it sends a signal that releases nitrous oxide (commonly known as laughing gas and historically used by dentists for anesthesia) in the penis. The release of nitrous oxide causes the smooth muscles within the penis to relax, allows blood to flow freely into the spongy tissue of the penis, and produces a firm erection. By blocking the breakdown of nitrous oxide, these drugs create a longer period of smooth muscle relaxation in the penis. This mechanism allows the penis to stay erect for a longer period of time.
Remember, these drugs are not desire drugs—they are capacity drugs. They do not create desire; rather, these medications give a man the capacity to exercise his sexual potential.
Love making, and sex in general, is much more than an erect penis simply interacting with someone else’s body for the sole purpose of releasing sexual tension. The sexual experience must go far beyond its physical characteristics. It must involve intimacy, sensuality, and an emotional connection based on respect and caring. Couples with problems in their interpersonal relationships should not turn to these drugs as a quick-fix solution. These drugs are designed to help individuals revive and maintain the sexual aspects of a healthy, intimate relationship. They should not be used as a substitute for resolving conflicts. Communication and discussion are more valuable than any medicine.
Dudley S. Danoff, MD, FACS