Opioid Tolerance: A Hallmark of Physical Dependence?

By November 12, 2021 January 4th, 2022 No Comments
Woman contemplating the relation between opioid tolerance & physical dependence

Tolerance is defined as needing to take larger amounts of a substance to achieve the desired effect.  The brain adapts by making changes that make you less sensitive to its effects. For example, if you take a medication for pain management every day, after several weeks or months your body will become tolerant to the drug’s effect.

Opioids are powerful drugs used to treat pain. Unfortunately, they are also highly addictive and can lead to opioid use disorders. This article explores how tolerance develops in opioid users and how it becomes a major part of physical dependence.

What Is Drug Tolerance?

The term “tolerance” comes from the Latin word meaning “to suffer loss.” In a medical setting. it describes when someone takes more medication than needed to get relief from their condition. In other words, people who have developed tolerance need higher doses of medications to feel the same way before they took the first dose.

When we talk about developing tolerance to something like alcohol, nicotine, or even opioids, our bodies adjust so that we don’t experience those feelings anymore even though we’re still consuming the substance. With opioids, this process is even more drastic. Due to the initial state of euphoria caused by opioid use, individuals with opioid use disorders are driven to administer large doses of the substance over time in order to achieve a similar effect.

When Should I be Concerned?

When taken exclusively in a medical capacity, there is usually little to no concern about experiencing a reduced effectiveness. Tolerance is usually only prevalent for chronic conditions, and proper medication management from your healthcare provider minimizes the risk of escalating tolerance.

However, when taken for recreational or non-medical purposes, tolerance can be a larger element of a dangerous cycle. Recreational use consists of overloading the body’s neurons with a substance. As the body adapts, individuals may find themselves needing to re-administer more and more of a substance to get the same level of euphoria, giving a drastically increased risk of overdoses and other health complications.

How Does Drug Tolerance Develop?

The development of tolerance occurs when the body becomes used to the presence of a particular substance. This adaptation happens because the body’s opioid receptors change how much of the drug is needed to achieve the desired effect. When the body becomes more and more tolerant to opioids, the effects of the drug decrease over time.1

Generally, when someone takes a medication regularly, their body adjusts to the regular dose so that it needs smaller doses each time. The process of tolerance begins when your body starts producing more receptors for the substance. These new receptors allow your brain to respond differently to the same amount of the drug. Your brain then adjusts so that fewer receptors are needed to produce the desired response. As time goes on, these adaptations continue until there are no longer enough receptors left to be affected by the drug. At this point, the person becomes physically dependent on the drug.

Tolerance occurs with many medications including alcohol, nicotine, caffeine, opioids, benzodiazepines, barbiturates, muscle relaxants, sleeping pills, and other sedatives.1

Can You Develop a Tolerance to Prescription Drugs?

If you have been prescribed opiates such as morphine or oxycodone for chronic pain, then you might be familiar with the concept of drug tolerance. You probably know that you must increase your dosage of these medicines to maintain the same level of relief from pain. But what do you think about when you hear the term “tolerance”? Do you associate it with addiction? Or maybe you just assume that everyone who uses prescription narcotics gets addicted. In fact, most patients don’t develop tolerance until they’ve taken the drug long enough to build up a tolerance.

Schick Shadel Can Help Provide Treatment for Opioid Use Disorders

Opioids are powerful painkillers used to relieve severe pain. They are often prescribed by doctors to patients who have undergone surgery or suffered a serious injury. However, opioids are highly addictive and can lead to dependence. Once someone becomes dependent on opioids, they must take higher doses to achieve the same level of relief. This results in tolerance, which means that the person needs increasingly larger amounts of the drug to feel the same effect. Eventually, the patient develops physical dependence on the opioid, meaning that he or she cannot function without the medication.

Schick Shadel Hospital offers one of the fastest and most effective treatment methods for opioid addiction. Our licensed professionals are ready to get you the care they need.

Call us at 1(800)CRAVING or visit our Contact Page here.

Frequently Asked Questions

What if I have a tolerance problem?

If your body has developed a tolerance to a medication you’re taking, it means the medication at your current dose has stopped working as effectively as it once did. However, if you are having this issue due to recreational drug use, it is vital to stop or to get help if you find yourself unable to stop.

What are the effects of opioid dosages?

Repeated exposure to escalating dosages of opioids alters the brain so that it functions more or less normally when the drugs are present and abnormally when they are not.

What causes opioid dependence?

Brain abnormalities resulting from chronic use of heroin, oxycodone, and other morphine-derived drugs are underlying causes of opioid dependence (the need to keep taking drugs to avoid a withdrawal syndrome) and addiction (intense drug craving and compulsive use).

What are the effects of opioids on addiction?

As we have seen, the pleasure derived from opioids’ activation of the brain’s natural reward system promotes continued drug use during the initial stages of opioid addiction.

What are the brain processes that activate opioid receptors?

The linkage of these chemicals with the receptors triggers the same biochemical brain processes that reward people with feelings of pleasure when they engage in activities that promote basic life functions.

What are the brain circuits that work with opioids?

One of the brain circuits that is activated by opioids is the mesolimbic (midbrain) reward system.

What is dopamine?

This system generates signals in a part of the brain called the ventral tegmental area (VTA) that result in the release of the chemical dopamine (DA) in another part of the brain, the nucleus accumbens (NAC).


  1. NIDA. (2017, January 12). Tolerance, Dependence, Addiction: What’s the Difference?. Retrieved from
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