Erectile Dysfunction Drugs

These days, the first line of treatment of ED is oral medication. There are three oral medications available on the market, all of which are PDE-5 inhibitors. The patient shortly before sexual activity administers these. Patients can also bring some change to their lifestyle (such as losing weight) to improve erectile quality.

Doctors and patients face a unique dilemma these days. All three oral medications (Viagra, Cialis and Levitra) with different molecular structures and pharmacokinetic properties variable have similar success rates. Apart from this, all three medications are rapidly absorbed from the gastrointestinal tract. Viagra and Levitra reach peak plasma concentrations within one hour and Cialis reaches the same by 2 hours.

Treatment Characteristics:

Food, in particular fatty foods, appears to inhibit both Viagra and Levitra but not Cialis when compared with the fasted state.

When taken with food, peak plasma concentrations of Viagra are reduced by 30% and the maximum concentration is delayed by one hour. Food also delays the maximum plasma concentration of Levitra by one hour, with a 20% reduction compared with the fasted state. The pharmacokinetics of each of the drugs is not affected by alcohol consumption although there is a causal link between alcohol consumption and erectile dysfunction. In any case, patients should avoid alcohol during ED treatment.

Viagra and Levitra both have a terminal half life of approximately 4 hours and for Cialis it is approximately 17.5 hours. None of the drugs have an immediate onset.

Most studies have demonstrated that the drugs have an onset action of between 30 and 60 minutes but the rate of onset varies between individuals. The PDE-5 inhibitors showed marked differences in their duration of effect. Viagra and Levitra showed 4-5 hours duration of effect while Cialis, consistent with its longer half life, showed up to 36 hours of duration of effect and thereby providing patients with a broad window of responsiveness.

Comparative Studies between Cialis, Viagra, Levitra:

Although comparative studies have been conducted to examine the relative effectiveness of each of the drugs, most of the studies eliminated patients who did not respond to Viagra. This can seriously undermine the value of the data produced.

One study by the University of North Carolina concentrated solely on patients for whom Viagra was not successful. This demonstrated in a 12-week study that Levitra was successful for 61.8% of patients for whom Viagra was not successful.

A double blind crossover study has also been conducted to test patient preference between Viagra and Cialis, however no such study has been conducted with Levitra. The study covered 219 patients who were randomized to determine the order in which they received Cialis or Viagra. After 12 weeks the patients were crossed over to the other treatment and of those who wished to participate in the extension period study, 70% decided to buy Cialis.

A recent open label multi-centre European study confirmed this with 71% wishing to continue with Cialis compared with 29% wishing to continue to buy Viagra. Taken together, these studies seem to demonstrate that the pharmacological differences between the PDE-5 inhibitors can affect patient preference.

The fact that a patient has not responded to one of the PDE-5 inhibitors does not necessarily mean that he will not respond to one of the alternative treatments from the same family of medicines.

Patients should not be deemed true treatment failures until they have failed to respond to the maximum dosage on at least 8 occasions. In a study, 55% of 137 men who had previously not responded to Viagra became successful after re-education and counseling.

Closing Lines:

In any case patients are advised to consult their doctors before taking any kind of erectile dysfunction medication or preparing to buy Cialis, Viagra or Levitra.