What Substance Abuse Does to the Gastrointestinal Tract

drugs affect the digestive system
What is The Gastrointestinal System:

It is the system responsible for breaking down and digesting food. The entire system consists of the mouth, stomach, large and small intestines, rectum, and anus. In addition to the mouth, stomach, and lining of the small intestine, the liver and the pancreas produce digestive juices that assist with the process of digesting. A number of different substance use disorders can lead to detrimental effects in this system.

Much of the information in this article is taken from the American Society for Addiction Medicine’s publication The ASAM Principles of Addiction Medicine.


Resources about Substance Abuse & Gastrointestinal

Alcohol & Gastrointestinal

Alcohol is not digested in the same way as other foods. About 80 percent of it is absorbed into the small intestine with the other 20 percent being absorbed through the stomach, depending on the amount of food in the cells in the system. Alcohol affects the gastrointestinal tract in a number of ways.
digestive problems caused by alcoholSome of the major issues include:

  • The organ particularly affected by heavy alcohol use is the liver because this organ is the main organ that processes alcohol. The liver gives priority to the processing and metabolizing of alcohol, and individuals who drink large quantities of alcohol increase the numbers of free radicals in the liver leading to liver damage and scarring. Scarred liver tissue does not allow free blood flow through the liver, and the liver does not work as efficiency as it should. This can result in cirrhosis of the liver, and this condition can be fatal.
  • Drinking large quantities of alcohol on an empty stomach also increases the acidity of the stomach. Individuals who eat and drink alcohol slow the absorption rate of alcohol and reduce this acidity. However, individuals who drink large amounts of alcohol will still have issues with acid in the stomach, and this acid can lead to issues with ulcers in the gastrointestinal tract. These can range from heartburn to a condition that chronic alcoholics often experience called Mallory-Weiss syndrome, which is internal bleeding caused by tears in the mucosal layer at the junction of the stomach and esophagus. Chronic alcoholics also often suffer from swelling of the tongue.
  • Alcohol is used as a disinfectant because of its ability to kill bacteria. Bacteria in the gut, lining of the mouth, and esophagus are fairly resistant to bacterialcidals such as alcohol in the short-term; however, individuals who consume large amounts of alcohol can damage these useful microbes and this can result in problems with digestion and other issues.
  • Chronic use of alcohol can damage the salivary glands. This can lead to issues with digestion and the inhibition of the substances that control the growth of pathogens in the oral cavity.

Individuals who neglect their diets as a result of their severe alcoholism may wind up with a severe neurological condition known as Wernicke-Korsakoff syndrome.

Wernicke-Korsakoff syndrome is reversible if it is caught early in its progression; however, chronic alcoholics with long-term nutritional deficiencies can suffer permanent effects, including severe dementia.

This syndrome is a result of poor nutrition and a lack of thiamine in the diet. The syndrome has three major components:

  • Nystagmus: This involves abnormal movements of the eyes.
  • Ataxia: This is difficulty controlling muscles, especially in regard to walking. Individuals may walk with a very wide base gate and shuffling movements.
  • Mental confusion and amnesia: This may initially begin as severe amnesia for recent events and memories. If left unchecked, it can become global, such that these individuals have trouble remembering important elements of their past. These individuals typically confabulate (just make up stories) to cover for their inability to actually remember events.

Opiate Drugs & Gastrointestinal

Opiate or opioid drugs include a number of different drugs for the control of chronic pain, such as morphine, Vicodin, OxyContin, as well as the illegal drug heroin and other derivatives of the poppy plant. Chronic use of these drugs can affect the gastrointestinal system in several different ways.

Opiate drugs will cause most individuals to become constipated even at therapeutic doses. Long-term use of opiates may result in damage to the bowels and produce a narcotic bowel syndrome, which is a result of the slowing down of the bowel functions associated with chronic opioid use or abuse. Individuals with this syndrome suffer from constipation, bloating, vomiting, nausea, and distention of the abdomen.
Every medication or drug is eventually processed and broken down by the liver, and abuse of any drug can result in issues with the liver. A number of different opioid drugs, such as Vicodin and Percocet, have high doses of acetaminophen in them. Acetaminophen is associated with liver damage when used chronically.
Chronic abusers of drugs like heroin are known to ignore issues with personal hygiene including their diet. This can result in a number of nutritional deficiencies in individuals with opioid use disorders that may or may not be reversible.

Tobacco & Gastrointestinal

smoking effects on stomachTobacco products are some of the most insidious drugs of abuse. Chronic tobacco use is associated with a number of health issues, including issues with the gastrointestinal tract.

Smoking can produce a variety of other issues, detailed below.

  • Heartburn: Tobacco decreases the lower esophagus’s ability to function and allows stomach acids to flow back into the esophagus.
  • Peptic ulcers: These are open wounds in the stomach or small intestine. A direct relationship between heavy smoking and ulcers in the duodenum and stomach has been identified.
  • Liver function: Smoking appears to affect the ability of the liver to function normally and can exacerbate issues related to the use of alcohol or other drugs.
  • Crohn’s disease: This causes inflammation in the linings of the intestine, and it is observed to be more common in smokers than nonsmokers.
  • Cancer: Smoking increases risk for the development of all forms of cancer.

Using oral tobacco products can result in similar effects to the digestive system as smoking, with the added risk of contracting a number of different cancers of the gastrointestinal system.

Cocaine & Gastrointestinal

Cocaine is a highly toxic and dangerous drug. Although cocaine is commonly snorted or smoked, it does result in issues with the gastrointestinal system.

Cocaine is associated with an increased risk of developing blood clots, and these can contribute to intestinal issues by blocking blood flow, resulting in necrosis and the presence of ulcers and perforations in the stomach and intestines. This can lead to an increased potential for the development of gangrene in the gastrointestinal system.
cocaine effects on stomachBecause all drugs are broken down by the liver, individuals who chronically use large amounts of cocaine risk serious liver damage.
Chronic users of cocaine suffer decreased appetite as a side effect of their cocaine use. This often leads to food bingeing episodes when these individuals are not using the drug, and this can cause some gastrointestinal issues. In addition, long-term and habitual users of cocainemay suffer a number of nutritional deficiencies.

Cannabis & Gastrointestinal

Cannabis products are the most commonly abused illegal drugs in the country. Although they are being made legal in some states, they are still illegal in all states according to federal statutes. There is research that suggests that cannabis can stimulate appetite in individuals who have certain diseases, such as cancer or HIV. There is also research that suggests that, in some individuals, cannabis use results in nausea and decreases appetite. Other research suggests that cannabis may have medicinal effects for a number of gastrointestinal disorders, such as irritable bowel syndrome, whereas other research suggests that it may be associated with these types of disorders in some individuals.

A very rare and somewhat controversial syndrome associated with chronic cannabis abuse, termed cannabinoid hyperemesis, consists of repeated vomiting and the need to continually bathe to relieve the sensations of nausea and the urge to vomit. There are only a few cases of this syndrome reported, and its validity is questioned. Some believe it may represent an extended form of some psychological disorder.


alcohol digestion problems treatmentAs is always the case, individuals who suffer the physical effects of substance use disorders need to engage in some form of structured substance use disorder treatment program in addition to receiving any specialized treatment for their medical issues. Simply treating the medical issue and continuing to engage in the substance abuse will not resolve the issue.

In addition, when left unchecked for long periods of time, many of the physical effects of substance use disorders may not fully remit even with intensive and specialized treatment. For example, individuals with severe nutritional deficiencies or extensive damage to the liver may suffer the ramifications of these conditions for the remainder of their lives even if they remain drug-free. The key to controlling many of these issues is to identify them early and initiate a plan of complete and thorough treatment and relapse prevention.

Unfortunately for many individuals with chronic substance use disorders, these disorders are left unchecked for significant periods of time, and the physical effects of these disorders continue to linger. The only guaranteed method of avoiding potentially harmful physical complications associated with substance abuse is to not engage in substance abuse. If a person is currently abusing drugs, the best solution is prompt, comprehensive treatment.

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