Tolerance to drugs or alcohol occurs when a person needs higher and higher doses of the same substance in order to achieve the same effects.
Types of tolerance include metabolic tolerance, acute tolerance, and functional tolerance.
Metabolic tolerance occurs when the body becomes more efficient at eliminating the drug or alcohol as it is being used, even in high concentrations.
Tolerance can be dangerous, because it can lead to drug dependence or addiction as a person struggles to achieve the same high or effects they felt with their first dose or use.
Metabolic Tolerance: The Process Of Metabolizing Drugs Or Alcohol
Metabolism is an important part of a person’s biochemistry. Determinants for a person’s individual metabolism include their size, age, gender, genetics, phenotype, and diet.
Having metabolic tolerance is not necessarily related to whether a person has a healthy metabolism or characterization in general.
Metabolic tolerance is often found in people with obesity or an unhealthy body weight or body mass.
Metabolism with drugs and alcohol refers to the process of their intake, use, and excretion, and can be considered in four stages.
Stage 1: Absorption
The absorption stage of metabolizing drugs and alcohol refers to the intake of the substance.
Stage 2: Distribution
During the distribution stage is when uptake happens, and the body decides what it is going to keep during the metabolism process.
Stage 3: Metabolism
Liver enzymes are very involved in the metabolizing of alcohol and drugs, and so are certain proteins produced by amino acids. This process produces metabolites.
Stage 4: Excretion
Excretion refers to the elimination of drugs and alcohol outward as the body attempts to reach homeostasis.
Long-Term Effects Of Metabolic Tolerance
Metabolic tolerance can produce a number of potential long-term side effects.
There are strong affiliations between tolerance of any kind with dependence and addiction.
Metabolic tolerance will almost certainly contribute to physical dependence and addiction in many cases with drugs and alcohol.
As a person keeps drinking or using a drug more and more to account for their tolerance, they may then find themselves relying on that substance in order to feel normal. They may no longer be able to function without it.
When organs like the liver, lungs, and kidneys are worked harder than usual in order to expel waste from the body, it can cause a great deal of damage with time.
Though metabolic tolerance allows these organs to eliminate waste faster, this does not mean it is good for them.
For instance, with metabolic tolerance involving alcohol, a person’s liver and hepatic system has to work extra hard to filter out the extra ethanol it is being fed to compensate for tolerance.
A person with metabolic tolerance is at an increased risk for overdose or death, because they can easily overestimate how much of a drug or alcohol is in their body.
This is because, with tolerance, they don’t feel the usual impairment that they would from such stimuli.
In an attempt to counteract their metabolic tolerance, a person may simply take too large of a dose.
Treatment Options For Drug Abuse
Tolerance is often a sign of addiction, which most often requires professional treatment.
Every substance abuse treatment center is unique and will have its own amenities and therapies when it comes to treating addiction.
The following are some of the treatment options you will find available at most healthcare centers for addiction.
Treatment options for drug abuse include:
- residential treatment
- partial hospitalization programs
- cognitive behavioral therapy
- dialectical behavior therapy
- pharmacology support
- medication-assisted treatment
- case management
- court-ordered rehab
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Addiction Resource aims to provide only the most current, accurate information in regards to addiction and addiction treatment, which means we only reference the most credible sources available.
These include peer-reviewed journals, government entities and academic institutions, and leaders in addiction healthcare and advocacy. Learn more about how we safeguard our content by viewing our editorial policy.
- National Institutes of Health (NIH): National Institute on Alcohol Abuse and Alcoholism (NIAAA) — Alcohol and Tolerance
- National Institute on Drug Abuse — Understanding Drug Use and Addiction DrugFacts
- National Library of Medicine: MedlinePlus — Substance use disorder
- National Library of Medicine: PubMed — The relationship of addiction, tolerance, and dependence to alcohol and drugs: a neurochemical approach
- The New York Times — Why Can’t I Hold My Alcohol Anymore?
- Plos One — An Evaluation of the Effects of the Novel Antipsychotic Drug Lurasidone on Glucose Tolerance and Insulin Resistance