Side Effects of Narcotics: Why Are Narcotics Dangerous?

Last Updated: December 18, 2019

Authored by Nena Messina, Ph.D.

It is safe to use narcotics as prescribed by medical providers. However, there is always a risk of narcotics side effects and dangerous adverse reactions that may arise. The side effects of narcotics vary according to medication type, a dosage which was taken, patient age, general health, and many other conditions.

There are side effects that may appear immediately after its administration, such as nausea, vomiting, and constipation. On the other hand, the side effects of some drugs may arise after using it for a prolonged period of time. The side effects of narcotics during pregnancy and breastfeeding are dangerous to both mother and baby. Mixing narcotics with alcohol can also be dangerous to health. Moreover, there is a list of narcotics that are illegal and don’t have medical purposes for use in the U.S., which means they cause hazardous health damage and are extremely addictive.

Short- And Long-Term Use Effects Of Narcotics

How do narcotics affect the body? Narcotics effects appear after binding to certain opiate receptors on the brain, spinal cord, and gut opiate receptors in the brain. These medications can relieve pain and cause feelings of well-being, but some side effects after their use still may appear. Narcotics cause an initial feeling of pleasure and euphoria, which makes a person desire to continue experiencing those feelings and may lead to addiction development.

What are the side effects of narcotics? Several physical and psychological narcotics side effects may appear after using them for the treatment of different medical conditions.

Topical drugs have fewer side effects than other product forms.

Short-Term Effects

Short-term narcotics symptoms may appear immediately after drug administration and may last for a few days. The short-term effects can severely affect the quality of life, and sometimes they may lead to discontinuation of drugs even though a patient is still having a medical problem. Different types of drugs may affect patients differently. For example, dizziness, nausea, and vomiting are more often associated with oxycodone than morphine.

Physical effects

There are some common physical effects of narcotics on the body that may persist for a short period, such as:

  • Drowsiness
  • Slow breathing
  • Constipation
  • Unconsciousness
  • Nausea
  • Intestinal bloating
  • Vomiting
  • Itching
  • Low blood pressure
  • Delayed gastric emptying
  • Hyperalgesia
  • Hyperalgesia
  • Muscle rigidity
  • Immunologic and hormonal dysfunction

constipation from narcotics


Why do narcotics cause constipation? Constipation is one of the most common side effects of narcotics. Constipation due to these drugs develops as these drugs reduce central nervous system activity, which can affect involuntary movements of the intestine. The muscle contractions that move food through the intestine slow down and the walls of the large intestine absorb more fluid. With less fluid in the large intestines, stools become harder, leading to constipation.


Another common side effect of these drugs is itching. Why do narcotics make one itch? These drugs trigger MRGRPX2, a receptor protein on the surface of mast cells, activation of mast cells increases histamine release that leads to itching.


Do narcotics make one sleepy? Yes, these drugs can make a person feel sleepy at lower doses. Narcotics cause sleepiness because of their drowsy properties, but people may continue taking them to reach deep sleep. It can cause slow irregular respiration that may lead to hypoxia and hypercapnia.

Urinary Retention

There is a relation when using narcotics and urinary retention. Such drugs as Tramadol may cause transient urinary retention due to its influence on the bladder sphincter. However, narcotics urinary retention adverse reactions may be eliminated after stopping the use of a drug, and this should be done under the supervision of a doctor.

Psychological Effects

Also, there are some short-term psychological side effects of these drugs that may appear, such as:

  • Anxiety
  • Paranoia
  • Confusion
  • Disorientation
  • Depression

depression from narcotics

Long-Term Effects

What do narcotics do to the central nervous system when they are used for a long time? There are several side effects of narcotics on the brain, such as psychological addiction and dependence. Moreover, the side effects of these drugs may be fatal. Here are common long-term physical and psychological side effects of narcotics:

  • Suppression of the immune system
  • Irritable bowel syndrome
  • Sleep disturbance
  • Psychological dependence
  • Addiction development

According to the National Institutes of Health, there is a relationship between chronic use of narcotics and blood pressure. The prolonged use of these drugs can lead to bradycardia and vasodilation, and as a result, can cause hypotension. The risk of tolerance development is also present. There were cases when long-term use of these medicines increased sensitivity to a pain, which is often hard to distinguish from tolerance.

Narcotics During Pregnancy

Why are narcotics dangerous during pregnancy? Using narcotics in pregnancy can affect the health of both baby and mother. Taking narcotics while pregnant may cause congenital disabilities such as:

  • Neonatal abstinence syndrome
  • Congenital heart defects (change shape of a baby’s heart)
  • Preterm labor (birth before 37 weeks)
  • Neural tube defects (congenital disabilities of the brain, spine and spinal cord)
  • Glaucoma (damage the optic nerve)
  • Stunted growth, causing low birth weight
  • Miscarriage or stillbirth
  • Gastroschisis

There are some indirect risks on the fetus while using these drugs during pregnancy, such as infection of Hepatitis C virus and malnutrition.

using narcotics during pregnancy

How long does the placenta hold narcotics during pregnancy? These drugs readily cross the placenta, and the fetus may become addicted to them. The baby may have narcotics withdrawal symptoms 6 hours to 8 days after birth. 

Some schedule 3 narcotics such as buprenorphine and schedule 2 prescription drugs such as methadone may be used during pregnancy in some cases. They are often used for treating drug problems in pregnancy.

Narcotics And Breastfeeding

Lactating women are often prescribed these drugs to control pain after a Cesarean section and childbirth. The medical providers and patients alike are concerned about using these drugs in a way that would not harm the baby. However, it is not safe to use narcotics while breastfeeding

What are the effects of narcotics during breastfeeding? Several side effects may appear in the infant while taking these drugs in breastfeeding:

  • The baby would become sleepier than normal
  • The breastfeeding patterns would change
  • The baby may have constipation
  • The baby may have breathing difficulties
  • The central nervous system depression may appear in a baby

According to the U.S. Food & Drug Administration, the risk of serious adverse reactions in breastfed infants such as excessive sleepiness and difficulty breathing may lead to infant death. It is important for healthcare providers and breastfeeding women to discuss the use of these drugs and to consider another safe alternative.

Narcotics And Alcohol

Alcohol and narcotics should not be mixed, because doing so could result in adverse effects on the brain and body. The negative effects of these drugs are even more deadly when they are mixed with alcohol, as both are central nervous system depressants. They induce a sense of relaxation and release calming neurotransmitters. Mixing narcotics and alcohol can lead to:

  • Mood swings
  • Loss of coordination
  • Liver cancer
  • Stroke
  • Anxiety
  • Internal bleeding
  • Brain damage
  • Vomiting
  • Overdose

mixing narcotics with alcohol

Overdose From Narcotic Drugs

Narcotics overdose occurs when someone has excessive unopposed stimulation of the opiate pathway. Overdose of these drugs is the leading cause of accidental deaths in the U.S. Overdoses most often occur when these drugs are used for recreational purposes, taken in high doses, or mixed with other illegal substances or alcohol.

How can narcotics cause death? These drugs affect the part of the brain that regulates breathing. Overdose may be accompanied by the stopping or slowing of breathing, which could end with coma and death. The signs of overdose include:

  • The face is extremely pale
  • Drowsiness
  • Loss of consciousness
  • A person feels clammy to the touch
  • The body goes limp
  • Pinpoint pupils
  • The fingernails or lips have a purple or blue color
  • Vomiting or making gurgling noises
  • Hypotension
  • Slow breathing
  • Slow heartbeat

overdose from narcotics

Can narcotics cause seizures? The use of these drugs in high doses may lead to brain overactivity, which can influence brain cells to send abnormal signals. Seizures can occur when the electrical system of the brain breaks down.

Overdose Prevention And Education

There are several ways to prevent or reduce the chance of experiencing an opioid narcotics overdose. The following are some guidelines that should be followed:

  • Ask a healthcare provider in detail about possible adverse reactions that may occur while taking medication.
  • Ensure ready access to naloxone. Naloxone is used as an antidote for narcotics overdose.
  • It is important for medical providers to follow prescription rules for narcotics while prescribing them.
  • It is recommended to take these as prescribed only. 
  • It’s important to check the pharmacy for legitimacy before buying narcotics online in order to avoid fake and low-quality drugs.
  • Don’t use these drugs for recreational purposes.
  • Hide bottles with pills from children.

Any medication of this type may cause side effects as well as dependence, which may result in addiction. Specialized addiction treatment would be required in such a case. It is recommended to find a suitable rehab center and start the battle with addiction as soon as possible.

Page Sources

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  2. Meyboom RH. Bladder dysfunction during the use of tramadol. 1999.
  3. Chen A, Ashburn MA. Cardiac Effects of Opioid Therapy. 2015.
  4. McQuay HJ, Jadad AR, Carroll D, Faura C, Glynn CJ, Moore RA, Liu Y. Opioid sensitivity of chronic pain: a patient-controlled analgesia method.
  5. Use of Codeine and Tramadol Products in Breastfeeding Women - Questions and Answers. U.S. Food & Drug Administration. 2019.
  6. Opioid Overdose. Centers For Disease Control And Prevention.
  7. Marjorie C. Meyer, Anne M. Johnston, Abigail M. Crocker, Sarah H. Heil. Methadone and buprenorphine for opioid dependence during pregnancy: A retrospective cohort study. 2015.
  8. Society for Maternal-Fetal Medicine (SMFM), Hughes BL, Page CM, Kuller JA. Hepatitis C in pregnancy: screening, treatment, and management. 2017.

Published on: October 11th, 2019

Updated on: December 18th, 2019

About Author

Nena Messina, Ph.D.

Nena Messina is a specialist in drug-related domestic violence. She devoted her life to the study of the connection between crime, mental health, and substance abuse. Apart from her work as management at addiction center, Nena regularly takes part in the educational program as a lecturer.


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