Tolerance to DXM: Next Steps & How to Lower It Safely

Medically Reviewed

DXM is an abbreviation of dextromethorphan, an over-the-counter (OTC) medication added to drugs treating symptoms of colds and flu, especially coughing. Tolerance to DXM does form with regular use, so it’s important to lower it safely.

Issues With Taking Too Much

If DXM is taken as directed on the packaging, the drug rarely causes side effects. However, taking too much of the drug can pose risks.

When too much of the medication is taken with other OTC medications like acetaminophen, side effects can be compounded. The combination of drugs may cause harm to other organs.

Abusing DXM to get high increases the risk of dependence, tolerance, and addiction.

Can You Become Tolerant To Over-The-Counter Drugs?

Tolerance, dependence, and addiction frequently occur together, but these conditions are not the same thing.

According to the National Institute on Drug Abuse (NIDA), addiction is a chronic medical condition involving compulsive behaviors. The term addiction is most often associated with substances like alcohol or cocaine, but addiction is associated with other behaviors such as gambling or shopping. If a compulsive behavior dramatically changes brain chemistry to release a flood of dopamine that triggers the reward system, it may become addictive.

When someone is addicted to a substance, such as opioids, the body and brain become used to the presence of the substance and how it adjusts brain chemistry. If the brain needs the presence of a drug to manage dopamine, serotonin, norepinephrine, and other neurotransmitters, then the person has become dependent on the drug. The drug must be in the body for the person to feel normal.

When the brain gets used to the presence of the drug and does not release floods of neurotransmitters in response to it anymore, this is known as tolerance. The brain needs more of the drug to achieve the initial effects.

A person can develop tolerance to any kind of intoxicating substance: prescription drugs like painkillers, recreational drugs like alcohol, and over-the-counter substances like DXM. If the substance is consumed regularly, the body gets used to it, so the effects — both positive like analgesia and negative like sedation or hallucinations — will occur less often.

It is rare for a person to develop a tolerance to OTC medications because these drugs are usually taken as needed to treat symptoms of mild illnesses like colds, flu, or seasonal allergies. However, DXM is a potent drug, especially when taken in much larger doses than are available over the counter, and it is possible to develop a tolerance to the substance while abusing it.

This can be very risky. DXM abuse can lead to brain damage and, in large enough doses, overdose.

What Is DXM?

Dextromethorphan is considered an opioid drug, but it does not lead to analgesia or pain reduction. Instead, DXM specifically suppresses coughing.

In large doses, DXM has been found to cause euphoria, or the feeling of being high, along with visual and auditory hallucinations.

Cough syrup being poured into a small plastic cupAbusing DXM leads to side effects that are similar to ketamine or PCP (phencyclidine; angel dust) along with sedation similar to opiates. Although DXM is considered safe, and it is in tightly regulated doses in more than 120 OTC drugs, there are illicit versions of this drug available online or on the black market in much higher doses.

When sold over the counter, doses of dextromethorphan are typically in a range of 15 to 30 mg (milligrams).

They are often accompanied by OTC analgesics such as acetaminophen, decongestants like pseudoephedrine, or antihistamines like chlorpheniramine. Dextromethorphan itself is an antitussive or a medication that suppresses coughing.

After low-dose opioid drugs like codeine were moved from OTC to prescription, DXM took that drug’s place in cough syrups, pills, and tablets. Dextromethorphan’s antitussive and sedating effects last for five or six hours at OTC doses. It is typically safe for the average adult to take a dose of DXM, even in combination with other OTC drugs, three to four times per day.

How Do Tolerance & Addiction Start?

You may stumble into the pleasant sedation and body high associated with DXM by accident if you take a larger-than-recommended OTC dose of a cold or flu medication. You may find powdered DXM or illicit tablets at a party and take a large dose to get high. Perhaps you start to abuse cough syrup along with other drugs.

There are many ways someone may begin abusing DXM, but taking more than recommended will lead not only to dangerous intoxication but also to dependence and drug tolerance.

The following effects are associated with DXM:

  •  Sweating
  •  Increased blood pressure
  •  Slurred speech
  •  Loss of motor control
  •  Changes to vision
  •  Stomach pain
  •  Lethargy or loss of physical energy
  •  Hyperexcitability, irritability, or rapid mood swings
  •  Dizziness or lightheadedness
  •  Drowsiness or fatigue
  •  Restlessness and nervousness, anxiety
  •  Nausea, vomiting, or stomach pain

There are four dose-dependent plateaus with different specific effects. The ability to reach these plateaus may change as the body becomes more tolerant of DXM. However, these are generally listed as:

  1. First plateau: Between 100 and 200 mg creates mild stimulation, similar to excess caffeine. This is the equivalent of three to seven OTC doses taken at once.
  2. Second plateau: About 200 to 400 mg of DXM lead to feeling high or euphoric, along with hallucinations. The hallucinations may be mild at first, but consuming more DXM leads to more intense hallucinations.
  3. Third plateau: Approximately 300 to 600 mg can cause distorted visual perceptions along with auditory hallucinations and a loss of motor control. You will perceive reality differently, and you will be unable to control your physical reaction time due to sedation.
  4. Fourth plateau: About 500 to 1,500 mg cause dissociative sedation, similar to ketamine’s effects.

If over-the-counter DXM is consumed in such large doses, there will be harmful side effects associated with the other OTC drugs found alongside dextromethorphan. Acetaminophen, for example, can cause liver failure if more than 4,000 mg (4 g) of the substance are taken at once.

Treatment For DXM Abuse

The U.S. Drug Enforcement Administration (DEA) has not scheduled DXM, according to the Controlled Substances Act (CSA), so it is widely available in small doses in pharmacies, drugstores, grocery stores, and anywhere that sells OTC medications.

You may be asked to produce identification to prove you are legally an adult in some states, which is a local method of reducing adolescent abuse of drugs like DXM. Some states also do not allow you to purchase more than one or two bottles or boxes of DXM-based medication at a time as a method of reducing substance abuse.

The best way to avoid abusing DXM is to follow the directions on the package and not take more than recommended.

If you have questions about the safety of consuming even OTC levels of DXM, talk to your doctor. Do not purchase any drugs online, especially those that contain more than 30 mg doses of DXM. Doses that high is dangerous and considered a form of drug abuse.

If you cannot stop taking drugs containing DXM because you enjoy the body high or want hallucinations, you are putting yourself at risk of severe side effects, including tolerance to the drug. While there are no medications approved to ease withdrawal symptoms associated with DXM, entering a medically supervised detox program is the first step to overcoming this form of substance abuse.

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