The Patient-centered Approach to Urine Drug Testing in the Chronic Pain Patient

November 12, 2009

At PAINWeek 09, Howard Heit, MD, FACP, FASAM, began his presentation "The Patient-centered Approach to Urine Drug Testing in the Chronic Pain Patient" by briefly discussing the concept of Universal Precautions in pain medicine, noting that the term originated from the infectious disease model.

Howard Heit, MD, FACP, FASAM, began his presentation "The Patient-centered Approach to Urine Drug Testing in the Chronic Pain Patient" at PAINWeek 09 by briefly discussing the concept of Universal Precautions in pain medicine, noting that the term originated from the infectious disease model. The Universal Precautions approach calls for a careful 10-point assessment of all persistent pain patients within the biopsychosocial model, and requires the physician to set appropriate boundaries before writing the first prescription. This approach "is a triage scheme for estimating risk for management and referral that, if properly and effectively applied, can reduce the overall risk of pain management and improve patient care," said Heit.

UDT is an important part of effective pain management, said Heit, calling it "another tool in the tool box for appropriate care of chronic pain patients." The purpose of UDT in clinical practice is to provide objective documentation of compliance with the mutually agreed upon treatment plan, to aid in the diagnosis and treatment of the disease of addiction or drug misuse, and to serve as a resource when the physician is acting as an advocate for the patient in family and social issues. Heit cautioned that UDT should never be used for forensic purposes.

He moved on to discuss testing capabilities, noting that, because urine "may be the best biological specimen for determining the presence of drugs," UDT is favorable in many ways to blood samples for drug testing. UDT can detect the parent drug and/or the metabolites in the patient's urine and reveal recent use of prescription medications and illicit drugs. But, he cautioned, UDT can only "assess the presence of a particular drug or metabolite in a specific concentration at a specific moment in time." UDT cannot diagnose drug addiction, physical dependence, or impairment. Nor can UDT tell the physician how frequently the patient was taking the substance or what dose was ingested.

During his presentation, Heit asked the audience a series of questions and then displaying their responses (relayed via handheld Audience Response Systems) on screen:

How commonly do you order a urine drug test (UDT) for your patients? - 54% responded "When I believe someone has high risk."

How well do you understand what a UDT can reveal? - 45% responded they were "comfortable" with their level of knowledge.

What best describes a patient-centered UDT? - 59% answered "Incorporating UDT into the Universal Precautions approach to pain medicine."

What is most important for a physician to understand before ordering a UDT? - 40% responded "Know the limits of the technology."

How is UDT used to diagnose addiction? - 50% answered that it is used "to reveal the levels of illicit and prescription medications in the patient's urine."

So, Heit asked, "whom should we test, and how often?" This is an important question in the context of pain management, because, Heit said, a non-rigorous, non-systematic approach to testing can lead to an unacceptably high percentage of drug use being missed. He cited one study that found that relying solely on the physician's ability to identify aberrant behavior in patients before calling for UDT resulted in more than 50% of subjects who were using illicit or unprescribed drugs going undetected. Because there are no are "no pathognomonic signs of addiction, misuse, diversion, or trafficking," practices must adopt a random testing protocol.

Heit said that clinicians should use their clinical judgment when it comes to determining the frequency of testing, but recommended that patients be tested as many times as necessary to document that the patient is adhering to the treatment plan. All new patients should be tested. Patients should also be tested when there is a major change in their treatment plan, when they are resistant to full evaluation, when they request a specific drug, and when they display aberrant behavior. Heit also said that UDT can be used to support referral for treatment.

Initial UDT should be done with class-specific drug panels, followed by more specific tests such as gas chromatography/mass spectrometry (GC/MS) in the event of a positive result, important because pain practices must identify the specific opioids their patients are taking. Heit recommended that pain practices select a testing lab, establish one or more routine panels; use screening immunoassays that can detect "NIDA 5" (cocaine, opiates, marijuana, PCP, and amphetamines), and screen for opioids using GC/MS.

Practices should consult with their lab regarding any unexpected results, and schedule an appointment with the patient to discuss abnormal results. This discussion should be conducted in a positive and supportive fashion to enhance the patient's readiness to change their behavior-his is an opportunity to strengthen the patient-physician relationship to support positive changes. Practices should also enter all results and interpretation in to the patient's chart.

If you order a UDT, said Heit, you have to know how to interpret results. And that means that practices must understand what urine drug concentrations of the drug and metabolites reveal, and be aware that there are numerous factors that influence the absorption, distribution, metabolism, and elimination of a drug. Test results should not be used to extrapolate backward to make specific determinations regarding ingestion of the prescribed controlled substance. The technology is not advanced enough to do this. Testing software and lab products have not been validated scientifically to give this information. Heir cautioned that interpreting UDT beyond the current scientific knowledge may put clinicians and patients at medical and/or legal risk.

There are several legitimate reasons for a patient to have a positive urine toxicology, said Heit, including legally prescribed medications, over-the-counter products and supplements, the ingestion of a substance that produces the same metabolite as an illegal substance (Heit pointed to the familiar example of patients testing positive for morphine and codeine after eating baked goods that contained poppy seeds), and errors in lab analysis.

Finally, Heit addressed the question of what actions the practice should take if a patient is discovered to have adulterated urine due to the use of one of the products that are available that claim to allow user to "beat" a drug test. Heit said that such an incident should prompt a discussion with the patient regarding the mutually agreed upon treatment plan that leads to "adjusting the boundaries for the treatment of chronic pain with opioids." The practice should also review its collection protocols. Physicians should always try to find the motivational behavior that might explain an abnormal test result, said Heit. However, when a patient commits a felony by diverting or altering his or her prescription it immediately severs the relationship. The physician must document the incident before discharging the patient from care.

In closing, Heit said that he believes that UDT is a "simple but effective tool in the assessment and ongoing management of patients" who are being treated with opioids for chronic pain, who are being treated for addiction, or who are being treated for other relevant medical conditions.

Miles D. Hyman, MD, an anesthesiologist who practices in North Carolina, attended Dr. Heit's presentation on UDT in pain management at PAINWeek. He said that he agreed with Heit that UDT is underutilized in pain management. Hyman said that patients seeking treatment for chronic pain at his practice are tested during their first visit. Patients receiving medical management for pain should be tested monthly. Hyman said that his practice has a strict policy regarding positive results: one positive test for illegal or illicit substances gets the patients a warning; a second positive test gets the patient discharged from the practice. Hyman said he disagrees somewhat with Heit's approach of placing a priority on identifying the cause of aberrant behavior in patients, saying that in his experience chronic users of illicit substances are unlikely to change their behavior.