The Science Behind the Overdose Dangers of Relapse, From an Expert

Drug overdose is now a leading cause of death in this country, according to the Centers for Disease Control. It is also a public health crisis that has left families in grief, decimated whole communities, and prompted an urgent nationwide search for solutions.

Dr. Albert Castellon, M.D., has devoted much of his life to helping those at the center of this epidemic—those whose addiction puts them at risk of relapse and overdose. Before joining FHE Health as Medical Director, Dr. Castellon was the chairman of the Department of Psychiatry of the Broward Health Medical Center. He also is an active member of the American Psychiatric Association, American Medical Association, American Association of Psychiatric Medicine, Association for Convulsive Therapy, and American Society of Addiction Medicine.

At FHE Health, Dr. Castellon oversees patients’ medical and psychiatric plans of care. The work demands familiarity with the neurobiological features of addiction, including relapse (a common feature of many chronic diseases, not just addiction).

In a recent interview, we asked Dr. Castellon to unpack the science behind relapse and why it entails a higher risk of overdose. He shared his answers in the Q&A below. Together, they make a strong case for why treatment is key, not just to reducing overdose risks but to successful long-term recovery.

The Dangers of Relapse Overdose and Death

Q: Why does relapse increase your risks of overdose? What medical/neurobiological/chemical factors make the body more vulnerable after being abstinent from a drug?

A: A relapse of substances, particularly opiates, can increase your risk of overdose and death. After some time of sobriety, the receptors in your brain that correspond to the drug (“mu receptors”) are no longer being stimulated. (The mu receptors are involved with opiate use and modulate many physiological functions like stress, mood, temperature, respiration, and motivation.) When you reintroduce the drug, the receptors are then more sensitive to the drug’s action.

In other words, when you are actively using, your body builds a tolerance to the drug. The active user then requires a higher and higher dose to reach the same effect. When the patient is sober but then relapses, they will commonly use the higher dose they were using, which causes the receptors to be overstimulated and produce a more intense reaction, such as cardio-pulmonary failure.

Drugs That Pose More Relapse Danger/Higher Overdose Risks?

Q: Do certain drugs pose more relapse danger (as in higher overdose risks)? If so, why?

A: The risk of overdose and death is particularly prominent in people who use opiates. Their brain will build a tolerance, requiring them to introduce a higher dosage to receive the same effect. For example, a patient may use one milligram for one week, then require two milligrams the next week to get the same effect, and then use three milligrams the week after to continue getting the same effect.

How Treatment Can Reduce Risks of Relapse Overdoses

Q: What measures can prevent an overdose (Narcan, etc.), and how do they work?

A: Narcan (naloxone) can help prevent death after an overdose has occurred. There are also medications that can prevent an overdose. Naltrexone is a medication that blocks the mu receptors, those same receptors involved with opiate use. Using naltrexone daily will generally prevent any relapse from causing overdose and death, since the medication is blocking the receptor.

There are other medications, too, such as Vivitrol, which is a type of naltrexone injection that lasts approximately 30 days. Typically, a patient will visit their doctor once a month to receive the injection. The medication also tends to decrease craving, a major factor in relapse.

Q: Why is treatment better at preventing relapse and its overdose dangers than trying to quit on one’s own?

A: Preventing relapse and its overdose dangers is more effective than trying to quit on your own. We are very aware that stopping an addictive drug—heroin, alcohol, Xanax, tobacco, etc.—is a difficult thing to do. People generally tend to relapse, often more than once.

The danger with opiates is that the relapse can cause overdose and death. Preventing the relapse with medication that reduces cravings, and preventing complications such as respiratory failure, is more effective than constantly trying to quit on your own. Medications such as naltrexone can help with cravings, which is generally the number one cause of relapse. It can literally save lives.

Of course, medication alone is not the answer. Treatment should correspond with medical, psychological, and social support.

The Need for Comprehensive Treatment

Rates of relapse for chronic diseases are quite high, including for addiction. As many as 40-60 percent of people with substance use disorders will relapse, due to factors like stress, cravings, triggers, and co-occurring mental health symptoms. This means that detox alone, whether professionally supervised or undertaken on one’s own, rarely is enough to overcome a drug problem, not to mention elude relapse and its dangers. Instead, it would seem from talking to Dr. Castellon that the most effective treatment for drug addiction will address its many complex facets and provide a multidisciplinary set of tools for managing them.

There is no one answer to the relapse overdose epidemic, but when more people have access to evidence-based treatment for opiate and other addictions, more lives will be spared. That is meaningful progress.