Certain combinations of medications are more prone to damaging kidneys. The infamous triple whammy, a combination of a diuretic, ACE inhibitor, and an NSAID painkiller is one of them. The article elaborates on the risk of this combination.
ACE Inhibitors: An Overview
One of the first-line medications for the treatment of hypertension of any cause is a medication from the class of medications known as Angiotensin-Converting Enzyme Inhibitors (ACEI). A close cousin of this class, with similar biological effects, is the family known as Angiotensin Receptor Blockers (ARB). These medications are highly effective in reducing hypertension and function through several mechanisms. One of the effects caused by these medications is a dilation of the arterioles (small arteries) exiting the kidney. This has the potential of reducing the pressure gradient of blood flow through the kidney which, in turn, can reduce blood flow through the kidney and impair renal function. In healthy kidneys, this effect is not noticed. When one kidney is not receiving enough blood and is therefore secreting hormones that increase blood pressure, these medications might even be an effective treatment for excessive hypertension.
When the patient is volume depleted
When a patient is dehydrated, he is effectively volume depleted. This means that the pressure gradient from the arterioles entering the kidney to the arterioles exiting the kidney is reduced. For this reason, patients with severe volume depletion can exhibit a decrease in renal function as blood flow to the kidneys is reduced. Damage to the kidneys due to decreased blood flow can be exacerbated if the patient is being treated with the aforementioned ACE Inhibitor or ARB. These patients are more prone to decreasing renal function significantly when they are volume depleted. Diuretic medications such as disothiazide, diuretics or furosemide have the potential of dehydrating a person when treatment is initiated. When on chronic treatment, patients are not usually dehydrated but their volume homeostasis is set to a lower point – this could be conceptually visualized as a sort of low key chronic dehydration.
Nonsteroidal pain killers
There is a very large family of pain killers, known as nonsteroidal anti-inflammatory drugs (or NSAIDs). These medications are generally available over the counter without the need for a special prescription. The family includes many of the medications used for fever and pain alleviation. These potent medications have many potential side effects. One of their mechanisms of action is by reducing certain inflammatory particles known as prostaglandins. Unfortunately, these very same prostaglandins function to ensure that the blood vessels supplying the kidney remain open. This means that these medications have the potential of reducing blood flow to the kidney. Indeed, patients with kidney disease should probably avoid this class of medications altogether.
The Triple Whammy
When the three medications listed above are taken together we get a situation called by some physicians a “triple whammy”. The NSAID pain killers reduce blood flow to the kidney, the ACE inhibitors reduce the pressure gradient of the kidney and the diuretics reduce the total blood volume. As a consequence, the kidneys can enter an acute renal failure which in extreme conditions can result in irreversible renal damage. It must be stressed that this combination can be achieved quite innocently. The person could be taking a combination of a diuretic and ACE inhibitor for hypertension and hypertensive heart disease as both would be indicated as part of proper medical treatment. All that would be necessary would be for a person to buy some over the counter pain killers for his rheumatism or fever and he could be presented to the emergency room with acute renal failure a week later.
Conclusion: Consult the pharmacist
Since renal failure and kidney injury are potentially serious problems, this is a clear-cut example of the key importance of the pharmacist in helping people to get the medications they need while avoiding those which could be potentially harmful to them. Anyone who takes any medication on a chronic basis should be sure to consult his treating physician or his local pharmacist before taking any other medication, even over the counter ones and even for brief periods.