Intravenous heroin addiction is one of the most gripping and powerful addictions there is; relapse rates for those who are lucky enough to ever find help are extremely high. Methadone is a powerful opiate analgesic drug that is given to heroin addicts in order to break the vicious cycle of using IV heroin, getting “high,” and then crashing in opiate withdrawal only to crave, seek and use again. Methadone shares certain similarities with heroin: they are both opiate receptor agonists that occupy the mu opiate receptor, they are both analgesics, and they can both be abused as well as used to the point of overdose. That said, there is a critical difference between methadone and heroin that is what makes methadone a useful tool in the treatment of heroin addiction. When a person injects heroin, the drug quickly gets into the brain. This results in the person experiencing an almost immediate high followed by a precipitous crash only a few hours later and, soon after, the experience of withdrawal symptoms if they do not use heroin again quickly. Regardless, it then takes the body about two to three hours to eliminate one-half of the dose that was injected.
In contrast, when a person takes a(n oral) dose of methadone, it is slowly absorbed into the body and so does not result in the quick high that is experienced with heroin because it takes several hours for that original dose to reach its maximum/peak concentration in the brain. It can take more than 24 hours for one-half of the dose to be eliminated by the body. It is this long elimination half-life of methadone that allows it to be administered once daily, for use in the treatment of heroin addiction. The ideal dose of methadone for a heroin addict is literally the dose required to eliminate feelings of drug craving and withdrawal symptoms all day long, so that the patient does not feel the need to go out and get high on heroin. Once the proper dose has been found, most patients can take methadone once daily for a long time to combat cravings and withdrawal symptoms brought on by heroin addiction.
There are patients who seem, for reasons both known and unknown, to metabolize methadone very quickly, resulting in a fast elimination of the drug after it is taken. These “fast metabolizers,” as they are called, have a difficult time achieving their correct therapeutic dose of methadone and find that in the evening after their dose or in the morning before their next dose, they experience opiate withdrawal symptoms (including sweating, shakes, twitches, goose bumps, runny nose, diarrhea, cramps and muscle aches) and a craving for opiates known as “drug hunger.” This is known to occur in some patients and even at fairly high doses. When this occurs, the proper procedure is to check what is known as a “peak” and a “trough” (blood) level of methadone in order to assess.
The peak level is done via blood draw approximately three hours after the morning dose is taken; this represents the highest level of methadone in the blood for that 24-hour cycle. The trough level, taken just before the following dose of methadone is given (which is usually the next morning, around 24 hours after the last dose), represents the lowest level of methadone present in the blood during that cycle.
Getting peak and trough levels is the only way to determine the therapeutic dose of methadone in patients who present with unexplained withdrawal symptoms prior to their next dose indicating that they might be fast metabolizers, might have a co-occurring substance abuse issue, might be using another drug causing more rapid metabolism, might be diverting medication, or might be suffering from a medical illness (either hepatic or non-hepatic).
While methadone has been repeatedly demonstrated to be an effective tool in the treatment of heroin addiction, it should be remembered that it is a powerful drug itself, it can be fatal in overdose, and its use must be closely monitored by medical professionals who are prepared to deal with clinical issues that may arise during treatment. One of the biggest challenges is to counsel patients that combining methadone with certain other medications, especially benzodiazepines, can be very dangerous and have been implicated in methadone-related deaths worldwide.
Intravenous heroin addiction medical expert witness specialties include addiction psychiatry, emergency medicine, psychiatry, and forensic psychiatry.