Posts Tagged ‘drug testing’

Why Drug Test?

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Every so often one of my established office-based buprenorphine (Suboxone) patients gets a little rebellious about being asked to take drug tests. They feel since they’ve been doing so well for so long, they no longer need urine drug tests. They say things like, “Don’t you trust me by now?” But it’s not about them or their character. It’s about the disease of addiction. I tell them some abbreviated form of the following:
• Patients in treatment don’t always tell me when they’ve relapsed. In order for addiction to thrive, lies must be told. Otherwise honest people sometimes tell outrageous lies while they are in the throes of addiction. I see this as part of the disease. It’s not about them. It’s not about me. It’s the addiction.
• It’s good medical practice. Like many chronic illnesses, relapses happen. It’s better to detect these as early as possible, to discuss what happened, and if/how we need to change their treatment. If a patient has relapsed to opioids, it may mean that I need to increase the dose of buprenorphine, if they were still able to feel an opioid high. If the relapse was to other drugs, it usually means we need to increase the “dose” of addiction counseling.
• There’s a gold mine of information in relapses. I ask my patient what happened immediately before the relapse. Was she around people who were using drugs? Did she use drugs to try to get rid of an unpleasant emotion? Did she use drugs because she became complacent? The answers can help decide how best to avoid relapses in the future. If a patient is fortunate enough to live through a relapse, she can get information she can’t get any other way.
• Drug screening benefits the patient by giving them accountability. Some patients are less likely to relapse with accountability. I’ve had patients say that the thought of having to talk about a relapse is enough to keep them from using drugs. This surprised me, but I’m glad.
• Drug screening also shows them I’m serious about their recovery. I’m not just going through the motions of writing a prescription and getting paid for the visit. I really want my patients to recover and get their lives back.
• I’m not a human lie detector. In the past, I smugly thought I could tell if someone had relapsed, so drug screens just confirmed what I already knew. After more experience, I know that’s not true.
• It’s the standard of care. Even if the other reasons aren’t compelling enough to do drug screens, the vaguely increased regulatory oversight of doctors who prescribe buprenorphine should induce them do drug screens. I know if my charts are ever audited by the DEA, my state’s department of health and human services, or my state’s medical board, I can show I’m doing things in the proper manner.
• I don’t want to prescribe medications that will be diverted to the black market. Some doctors say, with some justification, that buprenorphine is a safer drug than most other illicit opioids, and we should look at black market diversion of buprenorphine as a form of harm reduction. However, governmental types don’t see things that way. The DEA certainly doesn’t. I don’t want to prescribe buprenorphine to people with the criminal intent of selling part or all of it. When I do urine drug screening, if there’s no buprenorphine present, that’s a serious matter. If the patient isn’t using what I prescribe, it’s likely they are selling it. Since such diversion of buprenorphine endangers the whole program, it’s essential to stop prescribing for people who sell their medication.

These are my reasons for drug screening. Since I’m not going to stop doing them, addicts who refuse drug testing have to find new doctors. New opioid addicts who come to my office are told, both verbally and in writing, that I do drug screening. They can make their own decision about whether they want to see me as their doctor or go elsewhere. Most established patients comply with requests for testing after I explain the above reasons.

Urine Drug Testing

At April’s ASAM conference, I enjoyed an informative two-hour lecture on the finer points drug testing. Some of the information I knew, some I had forgotten, and some things I thought I knew, but I was wrong. Just goes to show me – again – I have to keep learning, because particularly in this field of medicine, things are always changing.

Dr. Peter Tenore, assistant professor at Albert Einstein College of Medicine, gave the two-hour presentation. He began with basic information about urine drug screening, and how to detect adulteration of a urine sample. Checking the urine creatinine and urine specific gravity are cheap and easy ways to see if a sample was adulterated. If the urine creatinine and/or urine specific gravity are below what is physically possible, it’s not human urine. These tests are fairly good, and detect most sample adulterations.

But besides these two methods, labs that do drug testing use ever more sophisticated ways to look for methods to thwart drug testing. These companies want to have good reputations. They want to be able to say they are savvy to the latest ways drug users try to cheat drug tests. These companies go to the same place drug users go for new ideas and technology – the internet. Testing companies buy the same products, advertised to beat drug tests, that the drug users do, in order to find ways to counter them. It’s a continuing game of cat-and-mouse.

Dr Tenore outlined the two types of tests done on samples to detect drugs. The first is cheap, quick, and fairly accurate, called the EIA, which stands for enzyme immunoassay. This test uses antibodies to identify the different classes of drugs. These tests are good for quick screening, but can have false positives. This mean a person has not used the drug, but the tests shows positive for the drug. In such a case, the same sample can be sent for more specific testing that won’t give a false positive, called GC/MS testing. This second test, more complex and more expensive, will show positive only if the drug really does exist in the sample. This second test meets the legal standard of beyond a reasonable doubt so if it’s positive…it’s positive.

Dr. Tenore took pains to remind us about the limits of drug testing, too. For example, oxycodone is a partially man-made molecule. The standard EIA (electroimmuno assay) tests for the morphine molecule, and oxycodone’s side chains, added to give it different opioid properties, often prevent the morphine antibody from attaching to the oxycodone molecule. In fact, if a patient prescribed only oxycodone is continually positive for opiates, oxycodone may not be the only opiate the patient is taking. Fortunately, there’s a specific EIA test for oxycodone, and most opioid treatment programs know to include this test, lest they miss important information.

I already knew that oxycodone doesn’t always show up as a positive for opiates, but surprisingly, many doctors who prescribe oxycodone don’t know this.

A few years ago, a patient being treated for chronic pain with oxycodone came for intake at the opioid treatment center where I worked at the time. His doctor, who prescribed oxycodone to treat a chronic pain condition, had just “fired” him. The patient was told only that there was a problem with his drug test. After talking with the patient, I didn’t feel he had the disease of addiction, and thus was not appropriate for admission to methadone maintenance at an opioid treatment center. This guy had never snorted pills, never used more than prescribed, never got extras from other doctors or off the street. He vehemently denied selling or giving away any of his oxycodone prescription, and said he took it as prescribed. This was puzzling.

I decided to call the testing lab, who said his sample was negative for opiates. I asked if the sample had been tested for oxycodone specifically, and was told “no.” Then with the patient’s permission, I called his pain management doctor, who was horrified at his mistake, and asked me to send the patient back to him immediately, which I did. Small errors like that can make big problems for patients.

The standard opiate EIA test works great for detecting drugs that get metabolized to morphine, such as heroin, codeine, and, of course, morphine. But special EIA screening tests must be done to detect the fully synthetic opioids like buprenorphine (Suboxone, Subutex), methadone, fentanyl, meperidine (Demerol), and tramadol. Other semi-synthetics are often negative for opiates on the standard EIA: oxycodone as described above, (name brands such as OxyContin, Roxicodone, Oxy IR, Percodan, and Percocet), hydromorphone (Dilaudid), and oxymorphone, (Opana). Hydrocodone usually does test positive on routine screening EIA.

Some drugs are metabolized into other drugs, which sometimes confuses doctors into thinking that two drugs have been used. For example, hydrocodone (Lortab, Vicodin) is metabolized into hydromorphone. So if I have a patient for whom I’m prescribing hydrocodone, I shouldn’t be surprised if, for some reason, I do a GC/MS test, and hydromorphone is also present. It does not mean the patient took Dilaudid. Similarly, oxycodone is metabolized to oxymorphone, and isn’t unexpected in the GC/MS of a patient prescribed Percocet.

In my next blog entry, I’ll explain how labs can tell whether a drug test is positive for opiates because the patient used heroin, or because the patient took prescribed medication.