What Is Drug Tolerance?

When your body develops a drug tolerance, you frequently use large amounts of the drug to achieve the previous “high” feeling.

What Is Drug Tolerance?

Drug tolerance develops when someone regularly exposes their body to a drug or medication. Acute tolerance means that the body is used to the substance and doesn’t produce the same effects or benefits in response to the drug as it once did. In these cases, doctors may change the regimen, increase the dosage, or prescribe another medication. Drug tolerance may develop during the first several times someone takes a drug, and it is also impacted by behavioral and genetic elements.

drug tolerance


Our knowledgeable team is ready to discuss your situation and options with no obligation required.
Call Us Anytime: 1-866-754-0180


The Difference Between Drug Tolerance and Drug Dependence

Though most people use drug dependence and drug tolerance interchangeably, they have different meanings. The difference highly depends on how your body reacts when the drug is either present or absent in one’s body. When someone takes a drug or medication, it activates specific cell receptors in the body. These receptors will eventually stop responding like they used to, and the body clears the medication faster when a tolerance has developed.

On the other hand, dependence leads to withdrawal symptoms when the dosage is suddenly reduced. In these cases, the body only functions normally when the drug is present. Dependence may happen with different types of drugs and may lead to addiction. Withdrawal symptoms depend on the medication being used. These symptoms may be mild, like vomiting or nausea, or may present in a more severe manner, including psychosis or seizures.

Do not stop using the drug or medication abruptly if you notice drug tolerance dependence and withdrawal symptoms. Seek advice from a doctor, who may gradually ease the drug dosage and recommend various other resources to support you as well.

Drug Tolerance Mechanisms of Action

Mechanisms of action describe how a drug or other substance produces an effect on the body. There are a few different ways in which this can happen, depending on the substance and person.2

Pharmacodynamic Resistance

This is when continuously using a drug produces a response in the body that dampens second-messenger systems or down-regulates drug receptors, reducing the pharmacological effects of the drug.

Receptor downregulation involves inactivating receptors in response to sustained stimulation, meaning that the more a drug is used and the body becomes used to it, the harder the body has to work to produce the same desired effect.

Metabolic Tolerance

Metabolic tolerance involves the body absorbing, distributing, metabolizing, and excreting drugs. When someone uses drugs for an extended period, the body creates a metabolic tolerance that renders these drugs ineffective. For this reason, doctors sometimes change or adjust prescription medications as time goes by.

Behavioral Or Learned Tolerance

Behavioral tolerance often refers to the decreased potency to elicit a particular behavior after continuous use. In other terms, behavioral tolerance may mean that a specific behavioral factor contributes to the development of tolerance. Behavioral tolerance is usually encountered when two circumstances happen. Firstly, when the effects of drug tolerance are specified by how you use the drug (snorting it, taking it orally, etc.), and secondly, when a drug tolerance develops when someone takes drugs preceding certain behavioral circumstances.

Conditioned Tolerance

Some researchers believe that the classical conditioning of drug-compensatory responses is a crucial factor in drug tolerance. Classical conditioning is a learned condition that happens from a person’s automatic responses.

The stimuli in the drug at the time someone uses it is a conditional stimulus (CS), while the effect the drug causes is an unconditional stimulus (UCS). Drug effects often disrupt homeostatic levels in physiological systems. For instance, alcoholism tolerance can lower the body’s temperature.

These disruptions provoke a compensatory response that works to restore the normal functioning levels of the body. This compensatory response then becomes an unconditional response (UCR). If someone continues to use the drug with the same stimuli, the body will show pre-drug cues that prompt the conditional tolerance. This then leads to the compensatory, therapeutic response.

The conditional drug-compensatory response (CR) tends to lower the drug’s effects when one uses the drug, leading to an acute tolerance.

Drug Tolerance & The Drug Abuse Cycle

The cycle of drug tolerance describes the process a person goes through as they develop tolerance to a drug. The duration of each phase depends on each person individually, the drug they’re using, among other factors.

Physical Dependence

When someone uses a drug for an extended period of time, the body and brain adjust accordingly, becoming dependent on it and failing to function normally without using it. This leads to using more of the drug, and over time, the body develops a tolerance to the new dosage again. Afterward, the body becomes dependent on the drug to work.

Withdrawal Effects

This is when the body suddenly stops receiving, or receives a reduced amount, or the drug, causing withdrawal effects. These effects are the body’s response to the absence of the drug in its system and can range from mild to severe depending on the types of drugs, the length of use, genetics, and more.

Psychological Dependence

A psychological dependence is the psychology of tolerance that involves mentally becoming reliant or dependent on a substance. Psychological dependency constantly tells the brain that the body needs the drug to feel good or to survive. When someone is psychologically dependent on a drug, the body continually wants to use the drug even after knowing its adverse effects.

Indicators of Drug Tolerance

The following are some warning signs of drug tolerant behavior:
  • Increased drug use
  • Frequently refilling prescriptions
  • Hiding pills
  • Mood swings
  • Excessive anxiety and worry
  • Obsession with the drug
  • Complaining that a drug is less effective
  • Change in attitude or personality
  • Lack of motivation
Drug Tolerance

What Are the Risks of Drug Tolerance?

If the body develops a drug tolerance, treating other conditions like chronic pain, immune-related conditions, seizure disorders, or mental health problems becomes a challenge. When this happens, doctors need to find new ways of managing symptoms for the patient effectively. The risks from developing tolerance may include:
  • Flare-up or relapse of a condition: the medication may cease being practical for a patient to take, like with antipsychotics and anti-seizure medication.
  • Need for higher doses: tolerance often leads to taking more of a drug to achieve symptom relief, which increases the drug’s adverse side effects.
  • Substance use disorders: taking large amounts of opioids may increase the risk of developing a substance use disorder and creating a physical and mental reliance upon the drugs.
  • Unintentional medication errors: these may occur from changing dosages or regimens and can lead to otherwise unexpected side effects.
  • Cross-tolerance: in some cases, building a tolerance to alcohol causes cross-tolerance to several other drugs, like Valium.

Get Help with Drug Tolerance at Concise Recovery

Though recovery can be challenging, you or a loved one can get helpful treatment and still live your best life. Concise Recovery will be with you every step of the way during recovery and can help with multiple aspects of the withdrawal process, craving stages, and subsequent inpatient or outpatient treatment options. Developing a drug tolerance is nothing to be ashamed of, and is often the body’s natural response to many prescribed medications. If you or a loved one notices any of the symptoms and risks listed above, reaching out to a treatment facility is the best way to get help quickly. We have doctors and medical specialists available around the clock.

Reach out today at Concise Recovery for more information on drug tolerance, the various treatment options, the different coping strategies we help with, and more. We are available to help with many other issues as well, including therapy and counseling.