Cocaine: Physiological effects
Last modified: Thursday, 25. December 2008 - 10:06 am
Cocaine is a central nervous system (CNS) stimulant that causes a significant increase in heart rate, respiration, blood pressure, and body temperature. According to DAWN, one in thirteen cocaine users go to the hospital to be treated for severe reactions that could be life-threatening. Sudden death can result from heart failure, respiratory failure, seizures, strokes, and cerebral hemorrhage. There is no antidote for cocaine overdose. Even if the adverse reactions do not result in death, they can do permanent damage to the body.
For years, scientists have known that cocaine interferes with the brain’s dopamine system. Dopamine is a neurotransmitter — a chemical that passes nerve impulses from one nerve cell to another, and dopamine is associated with movement, emotional response, and the ability to experience pleasure. Research indicates that serotonin transporters are also inactivated with cocaine use. Serotonin is another neurotransmitter, and adequate levels are associated with well-being. Low levels of serotonin in the brain have been linked to depression. Inactivation of dopamine and serotonin transporters leads to receptor over-stimulation and the “high.” Continued use of cocaine can result in long-term changes in the brain chemistry as receptors decrease in number. These changes can be persistent and even irreversible, and may be responsible for the feeling of depression that lasts long after withdrawal.
As late as the 1980s, there was a pervasive myth that cocaine is not addictive. This was because withdrawal symptoms were not thought to be physical. When a person addicted to a substance stops taking the substance, he or she experiences withdrawal symptoms. The withdrawal symptoms are unpleasant, and encourage the person to take the substance again in order to avoid the withdrawal. Cocaine withdrawal symptoms include an intense and irresistible craving for cocaine, depression or “crash,” and sometimes paranoia. It is now known that cocaine is powerfully addictive. Research indicates that after repeated ingestion of cocaine, nearly 100% of monkeys and rats tested will self-administer the drug. Cocaine is one of the easiest drugs to get animals to take willingly.
Cocaine is metabolized very quickly by the body. Within minutes, enzymes in the blood and in the liver split the cocaine molecule into two halves, rendering it inactive. Cocaine and its metabolites are excreted in the urine. The body’s efficient metabolism of cocaine causes the “high” to be relatively short-lived. This often causes cocaine users to take several doses of cocaine in a short time, which can increase the chances of an overdose.
Harmful side effects
The most serious effect of using cocaine is the possibility of sudden death. It can happen after the first use or anytime thereafter. Sudden death can occur with cocaine use alone, but it more commonly occurs when cocaine is combined with alcohol or other drugs. More common side effects include irreversible damage to the heart and liver, along with damage inflicted by strokes and seizures. Cocaine users are also at risk for addiction. Addiction is often viewed as a disease. It occurs when drug use is no longer a voluntary choice but an uncontrollable compulsion. Some crack users report addiction after just one use.
The point of ingestion determines the specific side effects. For instance, snorting powder cocaine over time will damage the septum and ulcerate the mucous membrane of the nose. Smoking crack cocaine can cause lung trauma and bleeding. Injecting cocaine into the veins often causes inflammation, infections, and carries a greater risk for contracting AIDS/HIV and hepatitis.
Cocaine use during pregnancy is especially dangerous. It can cause harm to both the mother and the baby. Cocaine causes spasms in the blood vessels, including those in the placenta. Sometimes placenta abruption (separation of the placenta from the wall of the uterus before the baby is born) and bleeding occurs, which can be fatal to the mother and baby. Children born to mothers who used cocaine during pregnancy are often termed “crack babies.” These babies tend to be abnormally small. Because of their low birth weight, they are 20 times more likely to die in their first month of life than babies of normal weight. The babies have an increased risk of mental retardation, cerebral palsy, and vision and hearing disabilities. Cocaine-induced prenatal strokes can cause permanent brain damage. Another common abnormality of these babies is their unusually small head. While they seem to have normal intelligence, studies indicate more behavioral problems for exposed children than unexposed children.
Long-term health effects
Cocaine constricts blood vessels and decreases blood flow. Using imaging technology such as magnetic resonance angiography (MRA) and transcranial Doppler sonography (TDC), scientists can see both short-term and long-term blood flow deficits in the brains of cocaine users. Long-term cocaine use can also cause atherosclerosis, or thickening of the blood vessels. Because of this, cocaine abusers in their thirties can have arteries as constricted as non-abusers in their sixties. With reduced blood flow to the brain, some cocaine abusers have shown cognitive deficits in attention span, memory, and problem-solving. Other effects include serious damage to the heart, lungs, and liver.
Cocaine also has a reputation for being disinhibiting. Users may take unusual risks that can lead to long-term consequences. These risks can range from sexual encounters to automobile accidents caused by poor judgment or aggression.