By Sandra Williams, MD and Keith Norris, MD

During a survey in 2003, an estimated 19.5 million Americans, or 8.2 percent of the population aged 12 or older, reported use of an illicit drug in the preceding month.1 Cocaine is one of the most frequently abused drugs, with 1 in 8 people estimated as having used cocaine between the ages of 18-28. It has recently been reported cocaine use is associated with permanent damage to the kidneys.

Although how this happens is still not certain, in a recent review, Jaffe and Kimmel stated, “The evidence to support kidney disease due to cocaine use is (more) convincing.”2 It is known cocaine can increase blood pressure. Very high blood pressure levels can lead to a heart attack or stroke and in some cases may cause temporary kidney failure. It used to be thought cocaine only caused sudden and temporary increases in blood pressure.

However, new studies have found cocaine can cause kidney and blood pressure problems that can be long lasting. Permanent kidney damage is called chronic kidney disease (CKD). Permanent elevation of blood pressure is called hypertension. Hypertension can also cause CKD.

A Brief History of Cocaine: From a food and medicine supplement to a leading cause of emergency room visits.
Cocaine comes from the coca plant which naturally grows in the Andes Mountains (Figure1). Coca is widely cultivated in Bolivia, Peru and Ecuador. But the lead producer is Colombia. Colombia is the source of 80 percent of the world’s cocaine. Until 1906 cocaine was used for medical treatments such as sleep problems and toothaches (Figure 2, on page 5). From 1885 to 1906 it was even used in the popular drink, Coca Cola®. In 1906 the Pure Food and Drug Act was passed and since then cocaine has no longer been used in foods and medicines. It has now become one of the most frequently abused substances. In 2005, there was an estimated 450,000 cocaine related emergency room visits.3 For substance abuse emergency room visits, cocaine was second only to alcohol. In 2003, the United States cocaine market was probably greater than $35 billion. That was more than the cost of care for all the patients in the United States with kidney failure.

How cocaine may cause CKD:
How cocaine causes kidney damage is not well known. Cocaine is known to cause damage to the body by causing spasms of blood vessels. This can lead to extremely high blood pressure levels. It can also lower blood flow to the heart, brain or kidneys. These are some of the main ways cocaine was thought to cause damage to the body’s vital organs. It now appears cocaine can damage the body more than blood pressure increases and spasms of arteries. It seems cocaine can also cause early hardening of the arteries. This can result in damage to many organs including the kidneys. Early hardening of the arteries in the heart and brain could explain why young people using cocaine get heart attacks or strokes. Early hardening of the arteries in the kidneys may also explain why many young people who use cocaine end up needing treatment for kidney failure.4 Special tests (angiogram) which look directly at the arteries of the heart show some young people who use cocaine have signs of artery spasms. In other young cocaine users these tests show the arteries of the heart are blocked due to hardening. It is now believed that CKD in people who use cocaine may be a result of both of these processes occurring in the arteries of the kidneys.

How cocaine may cause hypertension:
In addition to causing permanent kidney damage, cocaine can also cause permanent increases in blood pressure. This is known as hypertension. There are at least two different ways in which cocaine may cause hypertension. First, it is important to know the kidneys are fed blood by both large-sized and small-sized blood vessels or arteries.

When the large arteries become damaged or blocked by cocaine use, the kidneys are not able to receive enough blood. Whenever the kidneys’ blood supply is low, it releases substances, called hormones, to help fix this problem. These hormones increase the amount of blood going to the kidneys by raising the blood pressure. While this increase in blood pressure is helpful in getting more blood to the kidneys, it damages the rest of the body. People with blockage to the large arteries in the kidneys from cocaine use can therefore end up with hypertension. This condition is also called renal artery stenosis. It is an important cause of hypertension.

Cocaine can also cause hypertension if it causes damage to the small arteries that feed the kidneys. When these vessels become damaged, the kidneys try to increase the blood pressure. The blood pressure becomes high and remains high. It can be difficult to tell the difference between this form of high blood pressure caused by cocaine use and other forms of high blood pressure.

The abuse of many drugs
Many people who use cocaine also use other harmful substances. For example, many cocaine users also use alcohol, heroin or methamphetamines. Excess use of alcohol causes a wide range of problems. These include blood chemistry problems and dehydration. These abnormalities can further lead to low blood pressure and poor blood flow to the kidneys. If bad enough this can damage the kidneys. Methamphetamines and heroin can also cause kidney problems. When these substances are used along with cocaine the resulting kidney damage is worsened.

Conclusion:
Cocaine use should be avoided in general. Abuse of cocaine increases one’s chance of getting kidney disease and high blood pressure. Those who already have high blood pressure or kidney disease from other causes, will worsen their health problems by using cocaine. In addition this harmful drug may further damage the heart, brain or kidneys.

References:
1. Substance Abuse and Mental Health Services Administration. 2001 National Household Survey on Drug Abuse: Trends in Initiation of Substance Abuse. Rockville, MD: Substance Abuse and Mental Health Services Administration, 2003. Available at: http://www.oas.samhsa.gov/nhsda/2k3nsduh/2k3Overview.htm Date of Access: December 6, 2007.

2. Jared A. Jaffe and Paul L. Kimmel. Chronic Nephropathies of Cocaine and Heroin Abuse: A Critical Review. Clin. J. Am. Soc. Nephrol., Jul 2006; 1: 655 - 667.

3. Drug Abuse Warning Network, 2005: National Estimates of Drug-Related Emergency Department Visits. http://dawninfo.samhsa.gov/files/DAWN-ED-2005-Web.pdf Date of Access:
December 6, 2007.

4. Norris KC, Thornhill-Joynes M, Robinson C, Strickland T, Alperson BL, Witana SC, and Ward HJ. Cocaine use, hypertension and end-stage renal disease. Am J Kidney Dis 2001;38(3):523-528.

Dr. Sandra Williams is an endocrinologist at North Broward Medical Center, North Broward Hospital District in Deerfield Beach, Fla.

Dr. Keith Norris is a nephrologist at Charles R. Drew University of Medicine & Science, in Los Angeles, and is a member of the AAKP Medical Board of Directors.

This article originally appeared in the September 2008 issue of Kidney Beginnings: The Magazine.

Back