Male enhancement, dietary supplements and the risk of heart arrhythmias

I don’t know if I chose this subject because it would allow me the opportunity to write about ‘male enhancement’ as I approach the recommended age of my first colonoscopy; or if it is it because the authors of an article implicating Enzyte  as a source of potential cardiac arrhythmias are from my adopted hometown of Chicago; or perhaps it is the Tox Nerd in me that is fascinated by drugs that prolong the QT interval (try saying that 10 times fast).  Either way, while a blog on a supplement for male enhancement will probably induce eye-rolling –especially from my wife — it’s imperative that we are aware of the effects of the drugs and supplements we put into our bodies.

A few weeks ago, “Effect of Enzyte on QT and QTc Intervals” was published in the Archives of Internal Medicine and showed that in healthy volunteers, there was a ~10% increase in the length QT interval. 

Why is this important? 

The heart is a large muscle that beats in regular intervals and each beat is determined by electrical impulses.  The QT interval is the time it takes the heart to ‘repolarize’ and become ready to accept another electrical signal to beat again.  As the QT interval becomes longer (i.e. the longer it takes to repolarize the heart) that lag time makes it possible for a potentially fatal abnormal heart rhythm to occur.  This is due to incoming electrical commands for the heart to beat before it is electrically ready to do so (called “afterpolarizations”). 

In the healthy volunteers, the increase in QT interval was probably not enough to cause arrhythmias to occur; however in people with already increased QT intervals from age, disease or other drugs, it could be potentially dangerous.  Some medical conditions that can increase the QT interval are:

• Poor nutrition
• Congenital long QT syndrome
• Elderly age
• Diabetes
• Cardiac disease
• Electrolyte imbalances (low potassium, calcium or magnesium levels in the blood)

A short, non-inclusive list of drugs that can also cause a prolonged QT interval and may have an additive or synergistic effect includes:

• Anesthetics like halothane and isoflurane (if you are having surgery, be sure to tell your anesthesiologist all the drugs and supplements you are taking prior to surgery).
• Antidepressants including tricyclic antidepressants (TCA) and Selective Serotonin Reuptake Inhibitors (SSRI) such as Paxil, Zoloft, Prozac and Serotonin-Norepinephrine Reuptake Inhibitors (SNRI) such as Effexor.
• Antibiotics like clarithromycin, erythromycin; antifungal medications like fluconazole or ketoconazole;  fluoroquinolones such as levofloxacin, gatifloxacin, and moxifloxacin.
• Anti migraine agents such as sumatriptan, naratriptan and others.

This is only a short list of drugs that may interact with Enzyte or other drugs and supplemental over-the-counter (OTC) products that may prolong the QT interval.  There may be a whole other class of drugs not yet discovered that may affect how the ingredients in Enzyte are metabolized, thus making it last in the body much longer before it is excreted. This can also increase the QT interval. 

In the same edition of the Archives of Internal Medicine, there was commentary that stated avoiding this supplement until more information seems ‘justified and prudent’.  Fortunately for me, I have not needed to purchase this product (more eye-rolling from my wife 😉 ), but if I had, I would not be taking any more of it until more was known on the side effects of this supplement.

Until next Tuesday,

 Mike