Determination of methylphenidate and its metabolite ritalinic acid in urine by liquid chromatography/tandem mass spectrometry.

Methylphenidate (MPH) is a drug that is licensed for treatment of ADHD and also narcolepsy. Monitoring of the parent drug and its major metabolite ritalinic acid (RA) in urine is considered necessary to ensure compliance with treatment programmes. A rapid, simple and sensitive liquid chromatography/tandem mass spectrometry (LC-MS/MS) assay was developed for the determination of MPH and its metabolite RA in human urine.

Toxicity from the recreational use of 1-benzylpiperazine.

Aim: This study describes the demographics and symptoms of patients, who presented to the Emergency Department (ED) in Christchurch, New Zealand, with toxicity from 1-benzylpiperazine (BZP)-based "party pills." BZP use has become widespread among the 16- to 30-year age group in New Zealand. This study explores the relationship between plasma BZP level and adverse effects experienced by users.

Change in thrombus length on venous ultrasound and recurrent deep vein thrombosis.

Background: Despite successful treatment, deep vein thrombosis may not fully resolve in some patients. Consequently, in patients with new symptoms in a previously affected leg, noncompressibility on ultrasound cannot be assumed to be due to recurrent thrombosis; therefore, we sought to determine interobserver agreement on ultrasound measurements of thrombus length and identify the change in length that is likely to indicate thrombus extension.

Methods: Cross-sectional study of patients with previous proximal deep vein thrombosis and residual ultrasound abnormalities, but without symptoms suggestive of recurrence.