A Urine Screen Comes Back Positive for a Substance You Have Not Prescribed: Difficult Conversations, Part VIII

This is the eighth article in a series of eight articles by Ilene Robeck, M.D. regarding difficult conversations a primary care provider may have when dealing with patients with chronic pain. This series is meant to be a guide for primary care providers facing these situations. 

Difficult situation #8: A patient’s urine test comes back positive for a substance you have not prescribed. 

Advice: You have prescribed opiate medication for a patient you are treating for chronic pain. As with all of your other patients who receive opiates, this patient has signed an opiate agreement with you, acknowledging that there may be random urine screening. You do a urine screen and it comes back positive for a substance you have not prescribed. What do you do next?

At first blush this may seem like a very easy situation, and it may be, if you tell the patient the test result, and the patient admits to using the drug which was detected by the urine drug screen. If that is the case, opiates will need to be rapidly tapered and substance abuse treatment offered. A previously signed opiate agreement or previous review of policies concerning the use of illicit substances makes this discussion easier. Another problem you may face is the urine drug screen that comes back negative for substances you have prescribed. There are various reasons why this may have happened including, at a minimum, noncompliance with the treatment plan, or diversion of the medicine, or that the patient overused the medicine early in the prescription.

If the positive urine drug screen is for marijuana, the patient may deny drug use, but admit to being in the same room with an individual who is smoking. This response should be addressed in the same way as the positive urine drug screen for a patient who admits to using marijuana. There have been multiple studies to demonstrate that marijuana is not detected at the limit used in medical urine drug screens if the patient does not inhale it directly. In addition, patients who spend time with people who use marijuana are quite likely to be using themselves. This patient should be offered a non-opiate approach to their pain as well as substance abuse counseling. Their opiate should be tapered and discontinued.

A positive urine drug screen for a substance that was not prescribed, when the patient denies any use of this substance, will need to be handled quite differently. The screening tests that are used are associated with a number of false positives that need to be defined before a definitive decision is made. Explain to the patient that a confirmatory test will need to be sent out, and until that result is known a short prescription for the patient’s opiate will be written. Explain to the patient that this is necessary for safety reasons. Once again, this conversation is much easier if this policy was reviewed with the patient as early as possible in the process of prescribing opiates.

My experience is that many patients, who have actually used a substance inappropriately, will let you know once the confirmatory urine drug sample is obtained. I will still send out the confirmatory test, but will taper and discontinue opiates in this setting, and offer substance abuse counseling and/or treatment. A non-opiate approach to pain can then be utilized. Once the confirmation comes back, then the patient can be notified and appropriate steps taken if the urine drug screen was a true positive.

When a patient tests negative for prescribed substances a confirmatory test should still be sent. This is not only to look for the substance prescribed, but to look for metabolites of that substance. A urine drug screen may not pick up low levels of drugs, especially in patients who are rapid metabolizers. A confirmed negative test may indicate diversion for profit, sharing with friends or family, or the patient using their medication for unsanctioned dose escalation early in the month. The decision about where to go at this point depends on the etiology of the negative urine drug screen, as well as the patient’s behavior that accompanies it.

Providers in states with prescription drug monitoring programs can obtain invaluable information by checking those records. Patients, who you suspect are involved in illegal activity, can be searched through the town or county’s recent arrest records. These are usually public and can be used to check on patient behaviors outside of the office that may not be easily obtained from the patient history.

Diversion is a criminal offense. While there may not be enough data to report the patient to the authorities, further opiate prescribing is risky in patients who you believe may be diverting. This risk is to the community as well as to the patient.

Patients who share their medication with family members or friends may do so quite innocently and discuss this freely. Many people consider this to be acceptable behavior until they are educated about the risks. It is important to tell the patient ahead of time, what risks they may face when sharing their medication, as well as the risks to the person who is given the medication. Each provider or clinic will have to determine what their policy will be if a patient does this once, or more than once. Knowledge of repeated medication sharing should result in immediate discontinuation of the opiate.

Patients whose urine drug screen is negative because they do not take their medications as prescribed may be at high risk for an opiate related event. Consider whether non-opiate therapy is less risky and should be offered as another way to treat their pain.