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 patients after paracetamol overdosage. There was a positive error of between 40 and 700 % compared with a high-performance liquid chromatographic 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.
References
1.
AdriaenssensP. I.PrescottL. F. (1978). High performance liquid chromatographic estimation of paracetamol metabolites in plasma. British Journal of Clinical Pharmacology, 6, 87–88.
2.
ChambersR. E.JonesK. (1976). Comparison of a gas chromatographic and a colorimetric method for the determination of plasma paracetamol. Annals of Clinical Biochemistry, 13, 433–434.
3.
ClarkR.ThompsonR. P. H.BorirakchanyavatV.WiddopB.DavidsonA. R.GouldingR.WilliamsR. (1973). Hepatic damage and death from overdose of paracetamol. Lancet, 1, 66–69.
4.
CromeP.ValeJ. A.VolansG. N.WiddopB.GouldingR. (1976). Oral methionine in the treatment of severe paracetamol (acetaminophen) overdose. Lancet, 2, 829–830.
5.
DavidsonD. G.EasthamW. H. (1966). Acute liver necrosis following overdose of paracetamol. British Medical Journal, 2, 497–499.
6.
DouglasA.HamlynA. N.JamesO. (1976). Controlled trial of cysteamine in treatment of paracetamol (acetaminophen) poisoning. Lancet, 1, 111–114.
7.
GibsonP. F. (1972). Haemodialysis in paracetamol self-poisoning. Lancet, 2, 607.
8.
GilbertsonA. A.HallS. M.WhiteT. A.SmithJ. M.RobertsW. O. (1978). Cysteamine or n-acetyl cysteine for paracetamol poisoning?British Medical Journal, 1, 856–857.
9.
GlynnJ. P.KendalS. E. (1975). Paracetamol measurements. Lancet, 1, 1147–1148.
10.
HowieD.AdriaenssensP. T.PrescottL. F. (1977). Paracetamol metabolism following overdosage. Application of high performance liquid chromatography. Journal of Pharmacy and Pharmacology, 29, 235–237.
11.
HughesR. D.GazzardB. G.HanidM. A.TrewbyP. N.Murray-LyonJ. M.DavisM.WilliamsR.BerretJ. R. (1977). Controlled trial of cysteamine and dimercaprol after paracetamol overdose. British Medical Journal, 2, 1395.
12.
JollowD. J.MitchellJ. R.PotterW. Z.DavisD. C.GilletteJ. R.BrodieB. B. (1973). Acetaminophen-induced hepatic necrosis—II. Role of covalent binding in vivo. Journal of Pharmacology and Experimental Therapeutics, 187, 195–202.
13.
JonesG.ThomasP. (1977). Treatment of acute paracetamol poisoning. British Medical Journal, 2, 1224.
14.
LoveE. B. (1977). Measuring plasma paracetamol. Lancet, 1, 195.
15.
MaceP. F. K.WalkerG. (1976). Salicylate interference with plasma paracetamol method. Lancet, 2, 1362.
16.
MartinP. J.PowellJ. P. (1976). Measuring plasma paracetamol. Lancet, 1, 536–537.
17.
MitchellJ. R.JollowD. J.PotterW. Z.DaviesD. C.GilletteJ. R.BrodieB. B. (1973a). Acetaminophen-induced hepatic necrosis—1. Role of drug metabolism. Journal of Pharmacology and Experimental Therapeutics, 187, 185–194.
18.
MitchellJ. R.JollowD. J.PotterW. Z.GilletteJ. R.BrodieB. B. (1973b). Acetaminophen-induced hepatic necrosis—IV. Protective role of glutathione. Journal of Pharmacology and Experimental Therapeutics, 187, 211–217.
19.
PlakogiannisF. M.SaadA. M. (1978). Quantitative determination of acetaminophen in plasma. Journal of the Pharmaceutical Sciences, 67, 531–532.
20.
PotterW. Z.DavisD. C.MitchellJ. R.JollowD. J.GilletteJ. R.BrodieB. B. (1973). Acetaminophen-induced hepatic necrosis—III. Cytochrome P450-mediated covalent binding in vitro. Journal of Pharmacology and Experimental Therapeutics, 187, 203–210.
21.
PrescottL. F. (1978). Prevention of hepatic necrosis following paracetamol overdosage. Health Bulletin, 36, 204–212.
22.
PrescottL. F.NewtonR. W.SwainsonC. P.WrightN.ForrestA. R. W.MatthewH. (1974). Successful treatment of severe paracetamol overdosage with cysteamine. Lancet, 1, 588–592.
23.
PrescottL. F.ParkJ.BallantyneA.AdriaenssensP. I.ProudfootA. T. (1977). Treatment of paracetamol (acetaminophen) poisoning with N-acetyl cysteine. Lancet, 2, 432–434.
24.
PrescottL. F.ParkJ.SutherlandG. R.SmithI. J.ProudfootA. T. (1976). Cysteamine, methionine and penicillamine in the treatment of paracetamol poisoning. Lancet, 2, 109–113.
25.
PrescottL. F.StewartM. J.ProudfootA. T. (1978a). Cysteamine or N-acetyl cysteine for paracetamol poisoning?British Medical Journal, 1, 856.
26.
PrescottL. F.StewartM. J.ProudfootA. T. (1978b). SI, moles and drugs. British Medical Journal, 1, 856.
27.
PrescottL. F.WrightN. (1973). The effects of hepatic and renal damage on paracetamol metabolism and excretion following overdosage. British Journal of Pharmacology, 49, 602–613.
28.
PrescottL. F.WrightN. F.RoscoeP.BrownS. S. (1971). Plasma paracetamol half life and hepatic necrosis in patients with paracetamol overdosage. Lancet, 1, 519–522.
29.
ProudfootA. T.WrightN. (1970). Acute paracetamol poisoning. British Medical Journal, 3, 557–558.
30.
RigbyR. J.ThomsonN. M.ParkinG. W.CheungT. P. P. (1978). The treatment of paracetamol overdose with charcoal haemoperfusion and cysteamine. Medical Journal of Australia, 2, 396–399.
31.
RouthJ. I.ShaneN. A.ArredondoE. G.PaulW. D. (1968). Determination of N-acetyl-p-aminophenol in plasma. Clinical Chemistry, 14, 882–885.
32.
ScottC. R.StewartM. J. (1975). Cysteamine treatment in paracetamol overdose. Lancet, 1, 452.
33.
SolomonA. E.BriggsJ. D.KnepilJ.HenryD. A.WinchesterJ. F.BirrelR. (1977). Therapeutic comparison of thiol compounds in severe paracetamol poisoning. Annals of Clinical Biochemistry, 14, 200–202.
34.
SmithJ. M.RobertsW. O.HallS. M.WhiteT. A.GilbertsonA. A. (1978). Late treatment of paracetamol poisoning with mercaptamine. British Medical Journal, 1, 331–333.
35.
StewartM. J. (1974). Treatment of paracetamol overdosage. Lancet, 1, 1162.
36.
StewartM. J.SimpsonE. (1973). Prognosis in paracetamol self-poisoning. The use of plasma paracetamol concentrations in a region without a poisoning treatment centre. Annals of Clinical Biochemistry, 10, 173–178.
37.
WelchR. M.ConneyA. H. (1965). Simple method for the quantitative determination of N-acetyl-p-aminophenol (APAP) in urine. Clinical Chemistry, 11, 1064.
38.
WhiteT. A. (1976). Plasma paracetamol (acetaminophen) measurement. Lancet, 2, 696.
39.
WilkinsonG. S. (1976). Rapid determination of plasma paracetamol. Annals of Clinical Biochemistry, 13, 435–437.
40.
WienerK. (1978). A review of methods for paracetamol estimation. Annals of Clinical Biochemistry, 15, 187–196.
41.
WrightN. F.PrescottL. F. (1973). Potentiation by previous drug therapy of hepatotoxicity following paracetamol overdose. Scottish Medical Journal, 18, 56–58.
