From the Research
Azo compounds can potentially cause tachycardia as a side effect, though this is not common, and patients with pre-existing heart conditions or those taking other medications that affect heart rate should use them with caution. Medications containing azo compounds, such as phenazopyridine (Pyridium, AZO Standard, UTI Relief) used for urinary pain relief, may occasionally lead to increased heart rate in some individuals. These compounds work by providing local analgesia to the urinary tract but can be absorbed systemically, potentially affecting the cardiovascular system. The mechanism behind this side effect likely involves the compound's mild sympathomimetic properties or potential interaction with the autonomic nervous system.
According to a study published in 2020 1, phenazopyridine was found to be well-tolerated in patients with acute uncomplicated cystitis, with no serious adverse events reported. However, the study did not specifically investigate the effect of azo compounds on heart rate. Another study published in 2013 2 found that phenazopyridine can induce the expression of a soxS'::lacZ gene fusion, which may be related to its potential effects on the cardiovascular system.
It is essential to note that elevated heart rate is a significant risk factor for cardiovascular disease, as reported in a study published in 2004 3. The study found that an elevated heart rate is associated with a greater risk of developing hypertension and atherosclerosis, and that it is a potent predictor of cardiovascular morbidity and mortality. Another study published in 2008 4 explored the pathophysiologic mechanisms involved in the pro-atherosclerotic effect of elevated heart rate, apart from its association with sympathetic tone.
If tachycardia occurs while taking an azo compound medication, patients should discontinue use and consult their healthcare provider promptly. Most people tolerate these medications well when used as directed and for short durations, but monitoring for cardiovascular side effects is prudent, especially in vulnerable populations. A review published in 2016 5 highlighted the potential health risks associated with azo dyes, including their potential to cause allergies and other human maladies.
In summary, while azo compounds may potentially cause tachycardia, the available evidence does not provide a clear answer to this question. However, based on the potential risks associated with elevated heart rate, it is recommended that patients with pre-existing heart conditions or those taking other medications that affect heart rate should use azo compounds with caution.