Consumption of Movantik™ (Naloxegol) results in detection of naloxone in the patient's urine evaluated by confirmatory urine drug testing.

BACKGROUND: Many patients on chronic opioid therapy suffer from constipation, one of the most common side effect of opioids. Movantik™ (naloxegol) is an opioid antagonist that is recently introduced in the market to treat opioid-induced constipation and contains naloxegol as the active ingredient. Naloxegol is a pegylated (polyethylene glycol-modified) derivative of α-naloxol. Detection of naloxone in the patients urine after consumption of naloxegol was not reported by the manufacturer and may mislead the prescribing clinicians. This study was conducted to investigate the presence of naloxone in the urine of patients that consume movnatik in pain management clinics. METHODS: The presence of naloxone and naloxol in the urine of 45 patients that consumed naloxegol and 25 patients that consumed suboxone™ were investigated using a liquid chromatography mass spectrometry (LCMS) method. The urinary concentration of naloxone, naloxol, and their glucuronide conjugates were evaluated in five volunteers that took one pill of naloxegol for one day and one volunteer who took the pill for three days. RESULTS: Naloxone was detected in the urine of 45 individuals that were prescribed naloxegol. Urinary concentration of naloxone showed a distribution with a mean of 25 ±â€¯18 ng/ml. Consumption of one pill of 25 mg naloxegol resulted in the detection of naloxol and naloxone in the urine of 5 volunteers 1 h after taking the pill. Evaluation of urine specimens from 25 patients that consumed suboxone™, resulted in the detection of naloxone (180 ±â€¯187 ng/ml) and naloxol (6.3 ±â€¯7.2 ng/ml). CONCLUSIONS: This study demonstrated that consumption of naloxegol leads to appearance of naloxone in the urine of patients receiving opioid therapy in pain management clinics.

Storage of urine specimens in point of care (POC) urine drug testing cups reduces concentrations of many drugs.

BACKGROUND: Many clinical toxicology laboratories receive urine specimens in urine cups that contain point of care (POC) drug testing strips. We conducted this study to evaluate the effect on the stability of commonly measured drugs in the clinical toxicology laboratory when urine is exposed to POC urine drug testing cups. METHODS: Drug free urine was spiked with 85 drugs that were measured by a validated liquid chromatography mass spectrometry (LCMS) method after exposure to POC urine drug testing cups at ambient and 2-6 °C temperatures. Alterations ≥20% were defined as significant changes in the drugs concentration. RESULTS: Concentrations of amitriptyline, cyclobenzaprine, fentanyl, fluoxetine, flunitrazepam, nortriptyline, paroxetine, and sertraline were significantly reduced when urine specimens were stored inside POC urine drug testing cups for 24 h at ambient temperature. Storage of urine in urine chemistry dipsticks reduced the concentration of several drugs. When spiked urine was exposed to an increasing number of POC urine drug testing strips, the concentrations of some drugs were reduced in a dose-dependent manner. The drugs that were absorbed by POC urine drug testing strips were partially back extracted from the strips. CONCLUSION: Exposure of urine specimens to POC urine drug testing strips reduces the concentration of several drugs measured by LCMS method.