I have erectile dysfunction, but can’t take Viagra — what now?
Consider the case of Mr. Jones, a new patient I was helping in an ambulatory cardiac clinic. Most of my patients are on multiple medications for their heart conditions and other complicated issues, so I often review their medications to make sure everything is all right. This includes screening labs, checking vitals, reviewing past reports, and conducting drug interaction checks related to therapy. If there are any concerns, I’ll meet with the patient and make recommendations to the healthcare team.
At his last visit, Mr. Jones was prescribed Imdur (isosorbide mononitrate) to help with his heart condition. Reading through the notes, it looks like the Imdur worked. He was feeling better, so much better that he wanted to start having sex with his wife again. And here was the problem: Mr. Jone’s doctor had renewed his Cialis prescription. Quickly, I went from a moment of elation to consternation.
So what’s the problem? Well, if you really listen to the advertisements on television for erectile dysfunction (ED) medications, ignoring the blue tinted jazz from Viagra or the bathtubs in the sunset from Cialis, you may have heard the line “Do not take if you take nitrates for chest pain, as it may cause an unsafe drop in blood pressure.” You see Viagra, Cialis, and Levitra belong to the same drug class called Phosphodiesterase 5 Inhibitors (abbreviated as PDE-5 inhibitors), and they all share the same interaction with nitrates. Many patients wonder how bad can a ‘drop in blood pressure’ be. The answer, as we learned after Viagra came out, is this reaction could lead to heart attack in patients and potentially cause death, leading to a black box warning for the whole class of drugs like Viagra.
And Mr. Jones is on a nitrate, specifically Imdur. Fortunately for him, he had not yet used the Cialis. I advised him to avoid the combination, based on his significant cardiac history. But what can patients with ED and taking nitrates do to engage in an active sex life?
There is another drug that came out before Viagra, namely alprostadil, available under two brand names: Caverject and Muse. This drug works by relaxing the penile tissue allowing for easier blood flow leading to an erection. The plus side is it works relatively quickly; the downside is that is not available as a pill.
And there’s the rub. Caverject must be directly injected into the base of the penis to work. Muse is an intraurethral (a fancy way of saying ‘insert via urethra’) version of alprostadil that comes as small pellets that have to be inserted into the urethra by the patient.
For many patients, when I mention there is an another option to Viagra and other PDE-5 Inhibitors, their eyes light up, quickly followed by a nervous look as they find that it requires an injection to their penis or inserting something directly into their urethra. At this point, to not completely turn off the patient, I do try to get some information in to help them make a decision.
While both Caverject and Muse share the same active ingredient, there are some pros and cons each. Caverject tends to work much faster (<10 mins) as it enters the blood stream quicker, and has been found to work better. The draw back though is that it is an injection that needs to be applied to the base of the penis, and can cause irritation to the surrounding tissue. And let’s be honest, most men don’t want to engage in sex with a bruised member. It has a higher risk of causing priapism (basically an erection lasting for more than 4 hours, which incidentally is name after a Greek God called Priapus).
Muse on the other hand can cause a burning sensation to the penis along the urethra (this happens around 20% of the time) and it takes a little longer to work than the injectable formulation. But for men that don’t want a needle in their penis, it is an alternative. I generally recommend starting with Muse prior to moving onto Caverject because of this.
You may be wondering why alprostadil can’t just be applied directly to the penis as a topical agent instead of directly injecting/inserting it. A study conducted in 2006 in 1732 patients using a topical formulation did demonstrate some efficacy (though less than Caverject or Muse). Common side effects were burning sensation (for both men and women) though this was relatively low, with only 2.7% of subjects stopping its use. Currently, drug manufacturer Apricus Biosciences is looking to bring this formulation, named Vitaros, to market in the US (it is available in Europe at this time) but progress with regulatory approval has been slow. When and if this formulation makes it to the US market, it may be preferred by men who cannot take PDE-5 inhibitors.
Some men wonder about testosterone as an alternative for ED. The answer is that, unless testosterone plasma levels are at a low-level, adding more testosterone in a ‘normal’ individual won’t accomplish much, as clinical trials have shown. The other issue is that men with a cardiac history, adding testosterone to their therapy could prove highly risk to their health. If a patient does have low testosterone levels, it is possible to use testosterone supplements which come different formulation such as a topical ointment.
Bringing this all together, talking to Mr. Jones and those like him about these options takes some time and often requires some trial and error to find what works. At this time, I usually recommend most men to start with Muse and see if they have success with it, and if not they can move on to Caverject (they’re both relatively expensive at about $75 a dose). Some men are fine starting with Caverject right away and find it non-bothersome, but I would say it comes down to personal preference on what side effects are manageable for the patient. I do hope to see some advancements in other medications aside from PDE-5 inhibitors and expansion on the use of topical Alprostadil in the near future, which I feel more men would prefer.
