Acetaminophen-cysteine adducts during therapeutic dosing and following overdose

<p>Abstract</p> <p>Background</p> <p>Acetaminophen-cysteine adducts (APAP-CYS) are a specific biomarker of acetaminophen exposure. APAP-CYS concentrations have been described in the setting of acute overdose, and a concentration >1.1 nmol/ml has been suggested as a marker of hepatic injury from acetaminophen overdose in patients with an ALT >1000 IU/L. However, the concentrations of APAP-CYS during therapeutic dosing, in cases of acetaminophen toxicity from repeated dosing and in cases of hepatic injury from non-acetaminophen hepatotoxins have not been well characterized. The objective of this study is to describe APAP-CYS concentrations in these clinical settings as well as to further characterize the concentrations observed following acetaminophen overdose.</p> <p>Methods</p> <p>Samples were collected during three clinical trials in which subjects received 4 g/day of acetaminophen and during an observational study of acetaminophen overdose patients. Trial 1 consisted of non-drinkers who received APAP for 10 days, Trial 2 consisted of moderate drinkers dosed for 10 days and Trial 3 included subjects who chronically abuse alcohol dosed for 5 days. Patients in the observational study were categorized by type of acetaminophen exposure (single or repeated). Serum APAP-CYS was measured using high pressure liquid chromatography with electrochemical detection.</p> <p>Results</p> <p>Trial 1 included 144 samples from 24 subjects; Trial 2 included 182 samples from 91 subjects and Trial 3 included 200 samples from 40 subjects. In addition, we collected samples from 19 subjects with acute acetaminophen ingestion, 7 subjects with repeated acetaminophen exposure and 4 subjects who ingested another hepatotoxin. The mean (SD) peak APAP-CYS concentrations for the Trials were: Trial 1- 0.4 (0.20) nmol/ml, Trial 2- 0.1 (0.09) nmol/ml and Trial 3- 0.3 (0.12) nmol/ml. APAP-CYS concentrations varied substantially among the patients with acetaminophen toxicity (0.10 to 27.3 nmol/ml). No subject had detectable APAP-CYS following exposure to a non-acetaminophen hepatotoxin.</p> <p>Conclusions</p> <p>Lower concentrations of APAP-CYS are detectable after exposure to therapeutic doses of acetaminophen and higher concentrations are detected after acute acetaminophen overdose and in patients with acetaminophen toxicity following repeated exposure.</p

Patient reported outcome data following influenza A (H1N1p) vaccination in the 2009&amp;ndash;2010 season: web-based and telephone evaluation

Alan G Wade1, Gordon M Crawford1, Neil Pumford1, Alex McConnachie21Patients Direct, 3 Todd Campus, Glasgow, UK; 2Robertson Centre for Biostatistics, University of Glasgow, Glasgow, UKBackground: There has been worldwide interest in the safety of the pandemic influenza A (H1N1p) vaccines, although limited data are available from the vaccine recipients&amp;rsquo; perspective. This evaluation was designed to collect data from people who had received an influenza vaccination during the 2009&amp;ndash;2010 season using a web-based data collection tool supplemented by telephone reporting (PROBE).Methods: People scheduled to receive the influenza A (H1N1p) or seasonal influenza vaccines were recruited through media advertising and campaigns throughout the West of Scotland. Vaccine recipients participated in the evaluation by answering demographic and side effect questions using PROBE methodology on the day of the immunization, after 3 days, 8 days, 6 weeks, 12 weeks, and 26 weeks.Results: A total of 1103 vaccine recipients including 134 young children (0&amp;ndash;4 years) participated in the evaluation; 694 (63%) received H1N1p vaccine only, 135 (12%) seasonal vaccine only, 224 (20%) both H1N1p and seasonal vaccines, and 50 (5%) received H1N1p or seasonal vaccine with a non-influenza vaccine (eg, travel or pneumococcal). Overall, 42% of recipients reported experiencing a side effect after their baseline vaccination; the most commonly reported were general and arm side effects (&amp;gt;20%). Injection site discomfort/pain and flu-like symptoms were reported by 57% and 24% of recipients, respectively. A significantly higher proportion of the 960 H1N1p vaccine recipients experienced a side effect (44% vs 27%, P &amp;lt; 0.001) or injection site discomfort/pain (61% vs 26%, P &amp;lt; 0.001) than those receiving seasonal influenza vaccines. Female sex and H1N1p vaccination were associated with a significantly higher risk of injection site discomfort/pain, whereas the 70+ age group was associated with a significantly lower risk. H1N1p vaccine was well tolerated by children under 5 years with side effects reported at a similar frequency to that found in the total population.Conclusions: Safety and tolerability data from influenza vaccine recipients including young children (via parents/carers) can be effectively collected using an online questionnaire with a telephone option (PROBE). The influenza A (H1N1p) vaccine was well tolerated, but was associated with more local short-term reactions than the seasonal influenza vaccine.Keywords: safety, influenza, vaccination, H1N1, patient reported outcomes, side effect