What is Drug Tolerance, Know its Risks and How is Drug Tolerance Addressed?

Drug tolerance is a change in the body or brain of a person in which it is no longer able to respond to the medication it previously did. It happens when a person takes a particular drug for a long period of time. Gradually the receptors and enzymes in the brain and body get less activated by the drug making it less effective.

In this case to make the drug effective the doctor either increases the dosage or changes the prescription. Sometimes, a person needs to take an extremely higher dosage to achieve the high they are seeking.

Drug tolerance and drug dependence are different from each other in the way how the body reacts to the presence or absence of a specific drug.

In drug tolerance, there are certain cell receptors that activate when a particular drug stops responding the way it once did. There are also chances of the medication being cleared from the body faster.

In drug dependence, if the drug is not present or the dose is reduced, a person may experience withdrawal symptoms. The body functions normally when the drug is present and this can happen with many drugs. In some cases, drug dependence can lead to its addiction. The withdrawal symptoms may be nausea, vomiting, psychosis, or seizures. Therefore, if the body is dependent on a certain drug, it is important not to stop it suddenly. It should be gradually eased off.

Both tolerance and dependence are different from addiction.

Addiction is a health condition like any other chronic condition, which involves changes in brain activity. ⁽¹⁾ There is an increase in drug cravings as the neurotransmitters like dopamine are triggered.

Addiction is also known as substance use disorder. There is a driving need for the drug despite knowing that it may cause potential harm such as compromising on family, work, and social needs. There may be stress and anxiety around the time of getting the drug.

Drug tolerance can make the treatment of certain conditions challenging. These conditions include chronic pain, seizure disorders, mental health conditions, and immune-related condition.

Also, there are certain medications that can increase the risk of drug tolerance as they can increase and decrease the blood concentration of certain medications that may interfere with how effectively they work.⁽⁵⁾

Risks from developing tolerance include the following:

• Relapse and flare-up of the condition as the medications become not as effective as antipsychotics and anti-seizure drugs.^{(2, 3)}
• Due to tolerance to a specific dose a higher dose of the medication would be needed increasing the risk of side effects.
• Sometimes there is a risk of developing substance use disorder in some people.⁽⁴⁾
• Changes in dosing or routine due to tolerance may lead to unintentional medication errors.
• In certain cases there may be cross-tolerance to drugs like diazepam and valium.

Tolerance can develop to many classes of medication and it is absolutely normal. The doctor can help manage the effects of tolerance. Sometimes the doctor slowly stops the medication and restarts it depending on the condition. This gives the body time to reset.

Developing tolerance to certain medications would require a doctor to reevaluate the treatment, which can sometimes be challenging. It is because as the dosage is increased the risk of side effects is also increased and sometimes it may be harder to find other medications that work.

Some people may require additional supportive care such as psychotherapy to deal with the medication taper.

Drug tolerance can occur if someone is using a certain medication or a drug for a while and the body has developed a tolerance to it. In such a case, never stop taking the drug suddenly, but speak with your doctor to know how to manage drugs and tolerance and feel better. Sometimes, the drug tolerance may also become less effective over time.