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Clinical Pharmacokinetics of Alcohol in A CDAT Sample

This study investigates alcohol clearance in patients with alcohol dependence syndrome, indicating first-order kinetics. Clinical implications include potential biological diagnoses and support for drinking reduction therapy.

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Clinical Pharmacokinetics of Alcohol in A CDAT Sample

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  1. Clinical Pharmacokinetics of Alcohol in A CDAT Sample Robert Cohen Consultant Addiction Psychiatrist 9.11.2012

  2. Introduction • The way the body handles alcohol is of interest to a number of different groups

  3. Back calculation of alcohol is based on the assumption that the body clears 1 unit of alcohol per hour (zero order kinetics) • Zero order kinetics – same rate of removal however much alcohol left • First order kinetics – the more alcohol in the blood stream, the quicker it is removed

  4. Limited use of alcohol testing in the clinical setting • Result of testing often limited to positive or negative • Though the readings in blood, breath and hair are quantitative and need interpretation

  5. Alcohol testing • Ethanol (ethyl alcohol) or metabolites can be tested in a variety of matrices • Blood • Breath • Sweat • Urine • Hair • Breath alcohol levels closely parallel arterial blood levels Jones & Andersson, For Sci Int 2003;132: 18

  6. The breathalyser • Presents an easy method to test for alcohol levels • Easy to carry out the test • Reliable machinery

  7. This study Kingston CDAT LDASS

  8. The problem of interpreting breathalyser readings • When you take a breathalyser reading, you do not know • When the person last drank • How much they drank • But you may be able to gain an understanding if you know the rate of elimination, • which you can work out by taking multiple readings • This study is a pilot into the start of this question

  9. Methods • 20 consecutive patients who attended for assessment for alcohol / drug problems and whose breathalyser reading was more than 0.00mg/l • Breath alcohol level readings taken at regular intervals • Rate of elimination calculated and compared to the concentration • A composite made of all the readings

  10. absorption distribution clearance

  11. Results • 20 patients at the time of audit • 10 patients used only alcohol (‘alcoholics’) • 10 patients used alcohol on top of methadone (‘drug addicts’) • All met the criteria for a clinical ICD-10 diagnosis of mental and behavioural disorder due to use of alcohol, dependent type (F10.2)

  12. Results - Demographics

  13. Results – Breathalyser Readings

  14. All patients

  15. Alcoholics Drug Addicts

  16. Discussion - findings • Alcohol clearance in people with the alcohol dependence syndrome appears to follow first order kinetics rather than zero order kinetics • This is a composite picture of 20 patients, rather than a full study of individuals over the whole of the pharmacokinetic profile (absorption, distribution and clearance) • This is therefore a pilot study, generating a hypothesis for formal testing

  17. Discussion – clinical implications • Potential to lead to biologically based diagnosis of alcohol dependence • Biological support for drinking reduction as a therapeutic step prior to detoxification • Possible clinical-biological difference between those only using alcohol and alcohol/opiate users

  18. Discussion – clinical implications-1 • If there are clinical differences in the pharmacokinetics of alcohol between dependent people and non-dependent people, this may form the basis of a clinical biologically based test for alcohol use disorder, as opposed to history / rating scale based diagnosis • This is for future investigation

  19. Discussion – clinical implications-2 • This work may eventually elucidate the plasma level of alcohol associated with onset of withdrawal symptoms • However, clinical observations of patients with low plasma levels (e.g., 0.10mg/l) is mixed • Some show withdrawal symptoms • Others do not

  20. Discussion – clinical implications-2 • If withdrawal symptoms drive alcohol consumption in dependent patients then more rapid clearance may be lead to greater consumption, thereby creating a vicious circle • Helping people reduce consumption rather than attain immediate abstinence may therefore be an appropriate clinical goal as a step prior to detoxification

  21. Discussion – clinical implications-3 • There may be a difference between those who are in addition opiate dependent and those who are only dependent on alcohol • There is some evidence for this (Clarke, JSAT 2006; 30:191) • But the findings in this study may also be attributable to the higher level of drinking by opiate dependent patients

  22. Thank you for listening robert.cohen@sept.nhs.uk

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