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Comparing Viagra/Sildenafil to Cialis/Tadalafil

Posted on by Akash Kapadia, MD in ,

When patients find that they need erectile dysfunction/ED medication, their mind often goes straight to which medication is best. This decision can be challenging with all of the marketing swirling around ED treatment. Ultimately, however, the two most commonly known medications on the market are Sildenafil, the generic version of Viagra, and Tadalafil, the generic version of Cialis. Other than the dosages – 100 mg maximum for sildenafil and 20 mg maximum for Tadalafil, the two drugs have similarities and differences that every patient should know and understand.

For one, both are PDE5 inhibitors, which relax and widen blood vessels to allow for increased blood flow. This is the primary mechanism of their effectiveness, and it’s why they are so good for mild to moderate ED.

The drugs are also generally interchangeable in that both are safe and effective. If one does not seem to work or has problematic side effects, we can always try the other. Similarly, the risks associated with these drugs are quite similar. Flushing is relatively common, headaches can occur, and some patients will experience gastrointestinal upset. Viagra patients may experience a blue tint to their vision, which goes away when the medication is discontinued. Both drugs have a low risk of priapism or the dreaded four-hour erection.

With All These Similarities, It’s Worth Discussing Their Unique Qualities and Differences

First is the duration of action. Sildenafil should be taken about half an hour before sexual activity and lasts for a few hours thereafter. After this point, the drug is unlikely to allow for a sustained erection. On the other hand, Cialis has a longer mechanism of action and allows a patient to achieve an erection for up to 36 hours – this can vary based on an individual’s circumstance. In both cases, the drugs don’t increase desire, just the ability to develop and maintain an erection.

It’s also important to understand the circumstances around your sex life to see which drug is better. Based on the above, it would stand to reason that someone who is in a committed relationship with a stable and predictable sex life may be more inclined to use Viagra. On the other hand, a patient who is dating or out on the town may wish to be more spontaneous and take advantage of the longer duration of action of tadalafil.

This leads to another difference between the two medications. High-fat foods can counteract the function of sildenafil, while tadalafil is not affected by dietary habits. To that end, patients having a typical heavy meal at a date-night dinner may be better suited to tadalafil.

As for patient experience and preference, overall preference leans toward Cialis / tadalafil, likely due to the longer mechanism of action. Some patients also find that the overall incidence of side effects is slightly lower with tadalafil than with sildenafil. However, many other patients may find sildenafil suits them best with slightly more predictable erections.¹

Cialis / tadalafil can also be taken as a low dose daily and is approved and indicated as such to reduce the symptoms of enlarged prostate or BPH. This low-dose regimen may slow the worsening of Lower Urinary Tract Symptoms while also maintaining a baseline for spontaneous sexual activity.

The Bottom Line and Moving Forward

As urologists, our most important job is to figure out what works best with the fewest side effects possible. When patients are no longer able to achieve a suitable erection for their sexual activity, ED medications are a predictable and simple way to get back in the game. Of course, if the cause of ED is vascular, meaning the narrowing of penile arteries due to a buildup of plaque, the condition will likely progress, and in time, these ED medications will no longer work.

At this point, penile injections using a compound known as tri-mix or quad-mix may be what’s needed to maintain a good sex life. These injections are very reliable and offer very strong erections. However, they do come with an increased risk of an emergency known as priapism or an extended (4+ hour) erection absent of desire.

If patients are unhappy with medical therapies, at any point they can consider a penile implant, also known as a penile prosthesis. This is an elegant, subtle solution to giving patients with severe ED a reliable, on-demand erection.

It’s important to know that patients always have an option for regaining their sex life no matter how severe their erectile dysfunction is. The most important next step is to visit a qualified men’s health specialist and urologist like Dr. Kapadia to understand the options and pursue the best ones.

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Reference:

  1. Doggrell SA. Comparison of clinical trials with sildenafil, vardenafil and tadalafil in erectile dysfunction. Expert Opin Pharmacother. 2005 Jan;6(1):75-84. doi: 10.1517/14656566.6.1.75. PMID: 15709885.