False-Positive Urine Opiate Screening Associated with Fluoroquinolone Use

Random urine drug testing among patients receiving opioid therapy for cancer pain

BACKGROUND

There is limited information regarding the true frequency of nonmedical opioid use (NMOU) among patients receiving opioid therapy for cancer pain. Data to guide patient selection for urine drug testing (UDT) as well as the timing and frequency of ordering UDT are insufficient. This study examined the frequency of abnormal UDT among patients with cancer who underwent random UDT and their characteristics.

METHODS

Demographic and clinical information for patients with cancer who underwent random UDT were retrospectively reviewed and compared with a historical cohort that underwent targeted UDT. Random UDT was ordered regardless of a patient's risk potential for NMOU. Targeted UDT was ordered on the basis of a physician's estimation of a patient's risk for NMOU.

RESULTS

In all, 552 of 573 eligible patients (96%) underwent random UDT. Among these patients, 130 (24%) had 1 or more abnormal results; 38 of the 88 patients (43%) who underwent targeted UDT had 1 or more abnormal results. When marijuana was excluded, 15% of the random group and 37% of the targeted group had abnormal UDT findings (P < .001). It took a shorter time from the initial consultation to detect 1 or more abnormalities with the random test than the targeted test (median, 130 vs 274 days; P = .02). Abnormal random UDT was independently associated with younger age (P < .0001), male sex (P = .03), Cut Down, Annoyed, Guilty, and Eye Opener-Adapted to Include Drugs positivity (P = .001), and higher Edmonton Symptom Assessment System anxiety (P = .01).

CONCLUSIONS

Approximately 1 in 4 patients receiving opioids for cancer pain at a supportive care clinic who underwent random UDT had 1 or more abnormalities. Random UDT detected abnormalities earlier than the targeted test. These findings suggest that random UDT is justified among patients with cancer pain.

Urine Drug Testing in Cancer Pain Management

Urine drug test (UDT) is an effective tool used in chronic opioid therapy to ensure patient adherence to treatment and detect nonmedical opioid use. The two main types of UDT used in routine clinical practice are the screening tests or immunoassays and the confirmatory tests or laboratory-based specific drug identification tests such as gas chromatography-mass spectrometry, liquid chromatography-mass spectrometry, or tandem mass spectrometry. UDT produces objective data on some nonmedical opioid use that may otherwise go undetected, such as the use of undisclosed medications, the nonuse of prescribed medications, and the use of illegal drugs. It allows clinicians to initiate an open and effective conversation about nonmedical opioid use with their patients. However, the test has certain limitations that sometimes compromise its use. Its interpretation can be challenging to clinicians because of the complexity of the opioid metabolic pathways. Clear guidelines or recommendations regarding the use of UDT in cancer pain is limited. As a result, UDT appears to be underused among patients with cancer pain receiving opioid therapy. More studies are needed to help standardize the integration and use of UDT in routine cancer pain management. IMPLICATIONS FOR PRACTICE: Despite its potential benefits, urine drug testing (UDT) appears to be underused among patients with cancer pain receiving opioid therapy. This is partly because its interpretation can be challenging owing to the complexity of the opioid metabolic pathways. Information regarding the use of UDT in opioid therapy among patients with cancer is limited. This review article will improve clinician proficiency in UDT interpretation and assist oncologists in developing appropriate treatment plans during chronic opioid therapy.

Adolescent drug testing policies in schools

More than a decade after the US Supreme Court established the legality of school-based drug testing, these programs remain controversial, and the evidence evaluating efficacy and risks is inconclusive. The objective of this technical report is to review the relevant literature that explores the benefits, risks, and costs of these programs.

Testing for drugs of abuse in children and adolescents

Drug testing is often used as part of an assessment for substance use in children and adolescents. However, the indications for drug testing and guidance on how to use this procedure effectively are not clear. The complexity and invasiveness of the procedure and limitations to the information derived from drug testing all affect its utility. The objective of this clinical report is to provide guidance to pediatricians and other clinicians on the efficacy and efficient use of drug testing on the basis of a review of the nascent scientific literature, policy guidelines, and published clinical recommendations.

[Workplace testing of drugs of abuse and psychotropic drugs]

In France, workplace testing of drugs of abuse and psychotropic drugs is rarely performed; meanwhile it is a major public health problem. Furthermore, France is the European country that has been associated with the highest increase of the use of drugs of abuse, particularly cannabis. So workplace biological screening of drugs of abuse and of psychotropic drugs exposure is of major concern. New analytical techniques have been developed during the last years. The authors will consider analytical screening of drugs of abuse and particularly the comparison of analytical techniques applied to urine and saliva. The advantages and the disadvantages of these two matrices will be considered. Urinary and blood quantification will be reviewed, but also the interest of hair testing to explore chronic exposure. The research of psychotropic drugs in biological fluids is also a part of this paper. New analytical trends are promising and complete analysis of these substances will be soon routinely possible in blood using a single spot test.

Analytical interference of quinolone antibiotics and quinine derived drugs on urinary protein determined by reagent strips and the pyrogallol red-molybdate protein assay

OBJECTIVES

To investigate the analytical interference of drugs in urinary protein and to estimate the lowest interfering concentrations.

DESIGN AND METHODS

Drug supplemented urine samples were compared to the control with two reagent strips and the total protein was determined using Pyrogallol Red-Molybdate (PRM).

RESULTS

False-positive interferences occurred with Multistix 10 SG for hydroxychloroquine, levofloxacin and ofloxacin. No interference was observed with Combur 10 Test M. Statistically significant false-positive interferences were observed in the PRM assay with all tested drugs, and lowest interfering concentrations were mostly above estimated therapeutic concentrations. The PRM assay "confirmed" the results of the Multistix dipstick, so a real proteinuria could be presumed from the double analytical interference.

CONCLUSIONS

This is the first report of analytical interference by quinolone and quinine derivatives in the PRM assay. Special attention to patients using these drugs is needed to minimize errors in the interpretation of urinary protein results.

Advanced urine toxicology testing

Urine toxicology screening testing is an important standard of care in the addiction and pain treatment setting, offering a reproducible, unbiased, and accurate laboratory test to monitor patients and provide objective support for clinical observations. It has been shown that physicians do not have proficiency in the ordering or interpretation of these tests. This article is an attempt to respond to that need. Current antibody-based enzymatic immunoassays (EIAs) used for urine toxicology screening are useful to detect classes of drugs (ex., opiate) but cannot determine which specific drug (ex., morphine) is present. Gas chromatography and mass spectroscopy can determine exactly which drugs are present, allowing prescribed (or illicit) opiates and benzodiazepines to be identified. This article will discuss principles and details of opiate and benzodiazepine EIA and gas chromatography and mass spectroscopy urine toxicology testing. The approach to detecting patients attributing positive opiate EIAs to prescription opiates who are using heroin or other opioids will be reviewed. Cases of controlled prescription drugs that do not produce the expected positive urine tests (ex., oxycodone producing negative opiate screening tests) will be discussed. How to differentiate codeine from heroin and the role of poppy seeds in toxicology will be examined. The case of an anti-depressant drug that produces false-positive benzodiazepine results and antibiotics that cause positive opiate urine toxicology results will be reviewed. Common benzodiazepines (ex., clonazepam and lorazepam) that do not reliably produce positive benzodiazepine EIAs will be discussed. The approach to detection and management of all these types of toxicology cases will be reviewed, and it is hoped that the analyses presented will impart an adequate information base to medical providers and staff members of drug treatment and pain centers, enabling them to order and interpret these tests in the clinic more effectively as an integrated part of whole patient care.

Substance use in HIV-Infected women during pregnancy: self-report versus meconium analysis

We evaluated prenatal substance use in a cohort of 480 HIV-infected women and their uninfected children. Substance use was reported by 29%; the most common substances reported were tobacco (18%), alcohol (10%), and marijuana (7.2%). Fewer than 4% of women reported cocaine or opiate use. Substance use was more common in the first trimester (25%) than the second (17%) and third (15%) (trend p-value <0.01), and was associated with race/ethnicity, education, birthplace, age and marital status. For 264 mother/infant pairs with meconium results, sensitivity of self-report was 86% for tobacco, 80% for marijuana and 67% for cocaine. Higher discordance between self-report and urine/blood toxicology was observed for cocaine, marijuana and opiates in a non-random subset of mothers/infants with these tests. Findings suggest reasonably complete self-reporting of substance use as confirmed by meconium analysis. Illicit substance use was low and substantially less than that reported in earlier studies of HIV-infected women, but alcohol and tobacco exposure was prevalent.

Interferences With Urine Drug Screens

Qualitative urine drug assays are frequently used in conjunction with opioid contracts as a means of monitoring use of prescribed controlled substances as well as concurrent use of illicit substances in patients receiving opioids for chronic nonmalignant pain (CNMP) management. Appropriate use of these screening tests, in conjunction with opioid contracts, may provide the health care provider with additional information needed to safely prescribe opioids for selected individuals with CNMP. It is important for the practitioner caring for patients subject to random urine drug screening to understand interferences with the commonly used urine drug assays, as well as knowing options to confirm contested test results. We reviewed the literature on urine drug assay test interferences and present a summary of this information in this article.

Chemoinformatic methods for predicting interference in drug of abuse/toxicology immunoassays

BACKGROUND

Immunoassays used for routine drug of abuse (DOA) and toxicology screening may be limited by cross-reacting compounds able to bind to the antibodies in a manner similar to the target molecule(s). To date, there has been little systematic investigation using computational tools to predict cross-reactive compounds.

METHODS

Commonly used molecular similarity methods enabled calculation of structural similarity for a wide range of compounds (prescription and over-the-counter medications, illicit drugs, and clinically significant metabolites) to the target molecules of DOA/toxicology screening assays. We used various molecular descriptors (MDL public keys, functional class fingerprints, and pharmacophore fingerprints) and the Tanimoto similarity coefficient. These data were then compared with cross-reactivity data in the package inserts of immunoassays marketed for in vitro diagnostic use. Previously untested compounds that were predicted to have a high probability of cross-reactivity were tested.

RESULTS

Molecular similarity calculated using MDL public keys and the Tanimoto similarity coefficient showed a strong and statistically significant separation between cross-reactive and non-cross-reactive compounds. This result was validated experimentally by discovery of additional cross-reactive compounds based on computational predictions.

CONCLUSIONS

The computational methods employed are amenable toward rapid screening of databases of drugs, metabolites, and endogenous molecules and may be useful for identifying cross-reactive molecules that would be otherwise unsuspected. These methods may also have value in focusing cross-reactivity testing on compounds with high similarity to the target molecule(s) and limiting testing of compounds with low similarity and very low probability of cross-reacting with the assay.

Random drug testing to reduce the incidence of addiction in anesthesia residents: preliminary results from one program

Substance abuse occurs in approximately 1%-2% of anesthesia residents and nearly 80% of programs have had one or more resident (s) with such a problem. Education and control efforts have failed to reduce the frequency of substance abuse. Anesthesia providers have a professional obligation to be drug-free for the well being of their patients. We have instituted a program of preplacement and random urine testing of residents in anesthesiology in an attempt to decrease the incidence of substance abuse. We demonstrate that such a program is feasible, despite logistic and cultural obstacles. Larger multi-institutional studies will be required to determine whether instituting a program of random urine testing decreases the incidence of substance abuse in anesthesiology residents.

Levofloxacin-induced delirium with psychotic features

OBJECTIVE

To raise awareness of a rare but serious adverse effect of a commonly used medication.

METHOD

Report of a case.

RESULTS

A previously healthy 42-year-old woman presented with acute-onset delirium with psychotic features as a consequence of levofloxacin therapy. Withdrawal of the medication was associated with return of the patient's normal mental status.

CONCLUSION

The new quinolone derivatives (levofloxacin, sparfloxacin, grepafloxacin, trovafloxacin, gatifloxacin and moxifloxacin), also called gyrase inhibitors, are known for their potential to cause central nervous system-related adverse effects, including headache, dizziness and insomnia. Risk factors for neurotoxicity include renal insufficiency, underlying central nervous system (CNS) disease and increased CNS penetration of drug. Acute delirium resulting from levofloxacin therapy is an exceedingly rare complication that has been thought to occur more commonly in elderly patients. Here, we describe levofloxacin-induced delirium with psychotic features in a relatively young, otherwise healthy female.

Gatifloxacin Interference with Opiate Urine Drug Screen

A 48-year-old man participating in a residential treatment program was treated with gatifloxacin for a urinary tract infection. While taking the antibiotic, two urine screens were positive for opiates; results of previous urine opiate screens had been negative. Confirmatory tests using a different assay method, however, gave negative results for opiates. Two weeks after completing gatifloxacin therapy, the patient's urine screen was negative for opiates. Application of the Naranjo adverse drug reaction probability scale indicated that gatifloxacin probably was associated with this patient's positive urine opiate screen. Fluoroquinolones as a class are among several compounds that have demonstrated a propensity to cross-react with enzyme immunoassay urine drug screens for opiates. Occurrence of cross-reactivity appears to vary among individual assays. The mechanism by which fluoroquinolones cross-react with the immunoassay is unknown. Falsepositive results could have negative effects on patient care, and ramifications of a positive drug screen include possible dismissal from a substance abuse treatment program. Confirmatory analysis using a different assay method is therefore necessary to verify the presence of the target drug.