Why Does Heroin Cause Constipation, Weight Loss, Dry Mouth, & Vomiting?
Heroin is an opiate drug that is classified by the United States Drug Agency as a Schedule I controlled substance, meaning that it has no recognized medicinal purposes, is not believed to be a drug that can be safely used by anyone even if they are under the supervision of a physician, and has a significant potential for abuse and the development of physical dependence. All opiate drugs are central nervous system depressant drugs, meaning that they slow down the functions of the neurons in the brain and spinal cord. This central nervous system depressant action also accounts for many of the side effects that these drugs produce.
In addition, even though they are classified as central nervous system depressants, they affect the peripheral nervous system in the same manner. This means they also suppress the functioning of the nerves in the peripheral nervous system.
Use of heroin is associated with numerous potential side effects, and the side effects occur more often in individuals who use the drug more frequently or in higher amounts (or use the drug frequently and in higher amounts).
Because heroin is an illicit drug, actual clinical data regarding the estimates of the side effect profiles and percentages of people who use it are not readily reported. However, according to an article in the journal Therapeutic Advances in Chronic Disease, published in 2016, it is estimated that 40-90 percent of individuals who use opiate drugs medicinally experience some level of constipation. Individuals who abuse heroin would suffer from the same clinical syndrome (opioid-induced constipation [OIC]) as individuals who use opiates for medicinal purposes, but those who abuse heroin may experience OIC more severely.
The symptoms of OIC include:
- Hard and dry stools
- The need to exert extreme effort when defecating
- Decreased urges to defecate
- The feeling that one has not fully emptied the bowels after defecating
- Pain and cramping or distended stomach
Individuals with severe cases of OIC may develop bowel obstructions, which can be potentially serious and even fatal. According to the article in Therapeutic Advances in Chronic Disease, opiate drugs like heroin produce constipation through a number of different mechanisms.
- Because heroin and other opioids decrease activities in both the central and peripheral nervous system, they also decrease the ability of stool to move through the gastric system. These drugs increase nonpropulsive contractions in the small intestine and decrease propulsive contractions (referred to as peristalsis) through the intestines. This results in food that is eaten not moving through the digestive tract and increasing the potential for constipation.
- Opioids also slow the functioning of the activities of the autonomic nervous system (the portion of the peripheral nervous system that regulates involuntary actions), such that the functions in the stomach become partially paralyzed (a condition known as gastroparesis) and production of the digestive secretions is reduced. This results in food remaining in the stomach longer and in a decrease in the urge to defecate.
- Opioids suppress the functions of the sphincters, round muscles that separate the different parts of the digestive tract. When sphincters open, stool can pass through; when they do not open, stool cannot pass through the digestive tract.
- The intestines absorb water from the stool as it moves through the digestive tract. When stool movement is blocked, the intestines absorb too much water, and this makes it harder for the stool to move through the digestive tract. This leads to an increased potential for constipation.
Because heroin use blocks the functioning of the intestines, the typical treatments used to treat constipation, such as eating fiber, drinking water, etc., may not be effective in relieving the constipation from opiate use. Certain medications can be used to alleviate OIC in individuals who use the drugs medicinally; however, the majority of heroin abusers are not likely to go to their physician and complain about their heroin-induced constipation. Thus, constipation from heroin abuse can be a significant and even dangerous problem. This situation can lead to increased detrimental health effects associated with the abuse of heroin.
Heroin abuse suppresses numerous body functions as a result of its major mechanism of action. These suppressive consequences affect numerous organs and other body systems. Heroin abuse often results in the suppression of the pituitary gland, which is crucial in hormone production and release.
As with all drugs, these effects are dose-dependent. The more heroin one uses or the more often one uses it, the more it suppresses normal bodily functions. As a result of its overall suppressive effects, heroin also suppresses the production of hormones and chemicals that regulate appetite. This can include reduced production of substances in the digestive tract that signal that an individual has low levels of glucose or fat cells in their system and triggers the feeling of hunger.
In addition, heroin use also reduces motivation for individuals to perform their normal daily self-maintenance activities, including eating, washing, etc. Some individuals may not have the means to purchase or procure adequate supplies of food due to using their resources on drugs. Often, regular opiate users simply feel like just using drugs and lounging around doing very little. The result of all of these interactions can lead to significantly reduced food intake and weight loss.
In some people, heroin use may actually lead to weight gain as a result of the suppression of metabolism. While it is more common for individuals to lose weight as a result of appetite suppression and other effects that occur due to heroin abuse, some individuals may gain weight even if they eat less due to decreased metabolism effects. In addition, as mentioned above, the signals from the gastrointestinal system that an individual is full when having eaten food can also be suppressed, such that an individual does not achieve the feeling of fullness that they normally would feel, and they may actually wind up eating more food than they normally do.
Finally, individuals who suffer issues with severe constipation as a result of heroin abuse may have a significant reduction in appetite because their digestive tract is blocked up and already full, and this may result in significant weight loss. People can also lose weight as a result of chronic issues with vomiting and nausea, which are common side effects of opiate drug abuse, including heroin abuse (see below) and withdrawal. Those who feel nauseous or vomit may avoid food altogether and instead use heroin to deal with their pain and stress.
Chronic opiate use can lower the production of saliva, a condition referred to as hyposalivation or xerostomia. Using longer-acting opiate drugs and using opiate drugs more frequently are more likely to produce this effect.
Those who experience significant reductions in the amount of saliva they produce will experience the sensation of dry mouth. Chronic dry mouth can be particularly dangerous because saliva helps to clean bacteria away from the mouth and teeth, and a significant reduction in saliva production that is chronic can lead to sores in the mouth and even tooth decay.
Nausea and Vomiting
Nausea and vomiting are related side effects of opiate drug use. Nausea is often defined as an unpleasant feeling in the stomach and other areas the body that is associated with an inclination to vomit. According to a 2012 article in the journal The Annals of Palliative Medicine, opioid-induced nausea and vomiting are common side effects associated with the medicinal use of opiate drugs for pain control. Depending on the particular opiate drug, estimates are that at least 60 percent of individuals experience nausea and at least 30 percent have issues with vomiting when the drugs are administered for medicinal uses. Heroin abusers may experience similar, or even higher, rates of nausea and vomiting.
The Effects of Drugs
Opioid-induced nausea and vomiting can occur as a result of several different mechanisms.
- Perhaps the most common mechanism associated with the induction of nausea and vomiting in individuals who abuse heroin is the effect it has on the chemoreceptor trigger zone (CTZ). This is an area of the brain that is in the floor the fourth ventricle and in the medulla oblongata (the area that connects the brain and the spinal cord) that is sensitive to input from hormones and drugs in the blood. The CTZ communicates with the vomiting center in the brain stem to produce vomiting. Opioid use leads to stimulation of the CTZ that results in increases in neurotransmitters like dopamine, serotonin, norepinephrine, and the activation of the opiate receptors that trigger the vomiting center in the brain. Chronic use of heroin can lead to stimulation of the CTZ, which can lead to chronic issues with nausea and vomiting.
- Chronic use of heroin can also lead to increased vestibular sensitivity. The vestibular system is a complicated system in the inner ear and the brain that is involved in the control of eye movements and balance. When the vestibular system is overactive, this can lead to dizziness, vertigo, nausea, and vomiting.
- As mentioned above, chronic use of opiates like heroin leads to delayed gastric emptying (constipation), which can result in issues with chronic nausea and vomiting.
- Individuals who have developed physical dependence on heroin and are unable to use the drug for a sufficient length of time may experience a withdrawal syndrome. Physical dependence occurs as a result of the individual’s system regulating its production of neurotransmitters, hormones, etc., to account for the presence of the drug in the system. When the levels of the drug in the person’s tissues drop, the system is thrown out of balance, and this can lead to numerous negative effects, including nausea and vomiting.
The effects listed here are not the only types of negative side effects that can occur with chronic use of heroin or other opiate drugs. The effects of opiate drugs are complicated, and different individuals using the same amount of heroin for the same length of time may have significantly different experiences. The side effects that occur in any individual depend on the person’s genetic makeup, metabolism, environmental experiences, and even psychological makeup.