Inappropriate Methods for the Emergency Determination of Plasma Paracetamol

Abstract

Methods for the estimation of plasma paracetamol which depend on acid hydrolysis to p-aminophenol without a prior extraction step also measure inactive metabolites which are present in high concentrations. The extent of the overestimate obtained with such methods was determined using 24 samples from patents after paracetamol overdosage. There was a positive error of between 40 and 700% compared with a high-performance liquid chromatography reference method which measured only unchanged paracetamol. These non-specific methods should not be used to determine the need for specific therapy in patients with paracetamol poisoning.

On-line microfluidic sensor integrated with an enzyme-modified pre-cell for the monitoring of paracetamol in pharmaceutical samples

“…Many analytical methodologies have been proposed for the determination of paracetamol including titrimetry [5], spectrophotometry including spectroflourometry, near infrared reflectance spectrometry, Raman spectrometry, Fourier transform infrared spectrophotometry [6][7][8][9][10][11][12][13], chromatography [14,15], chemiluminescence [16][17][18], enzymatic analysis [19,20] and electrochemical methods [21][22][23] have been proposed for the analysis of paracetamol in pharmaceuticals or biological fluids. The electrochemical methods are also popular for this application because the cost is low and time consuming is less.…”

The Treatment of Acetaminophen Poisoning

“…Those that depend on direct acid hydrolysis to p-aminopheno1 without prior extraction also include acetaminophen conjugates present in high concentrations, and may overestimate the true result by as much as 700% (77). Fortunately, cystea mine, methionine, and N-acetylcysteine have been dramatically effective in preventing liver damage after acetaminophen overdosage, and despite all these difficulties their value is not in doubt.…”

Experiences with a Regional Quality Control Scheme for Salicylate and Paracetamol over a Period of Two Years

“…Hence, plasma samples from subjects who have ingested paracetamol may give different results with different assay techniques (Stewart et al, 1979). It is usually considered preferable to measure only the active unchanged paracetamol, and as the methods used by participants in the scheme were of types regarded as not measuring metabolites, no investigation of that aspect was attempted.…”