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what is therapeutic drug monitoring?

Therapeutic drug monitoring (TDM) is an area of clinical chemistry that specialises in measuring medication levels (concentrations) in patients, usually through blood samples but also through saliva samples. Because anti-epileptic drugs are among the types of drugs that can be easily under dosed or over dosed, they are particularly suitable for monitoring. The measured levels are used by the doctor to adjust each patient’s individual dosage and schedule to each patient’s individual therapeutic requirement. Thus, drug efficacy (the anti-epileptic effect of a drug) is kept to a maximum while the undesirable side effects are kept to a minimum.

Monitoring antiepileptic drugs

There are now 27 anti-epileptic drugs (AEDs) licensed for the management of patients with epilepsy in the UK. We offer a TDM service for 24 of these drugs and 2 pharmacologically active metabolites. During the past 10-20 years therapeutic monitoring of anti-epileptic drugs has served to substantially enhance the management of patients with epilepsy because drug administration (prescriptions) can be individualised.

Epilepsy Society’s Therapeutic Drug Monitoring Unit (TDM)

We provide a TDM assay service for AEDs and a pharmacokinetic consultation service (looking at how drugs distribute in the blood over time) to help individualise patient drug therapy. We carry out detailed pharmacokinetic investigation of individual patients who have experienced an unusual clinical response to drugs during therapy or following overdose.

The Unit is accredited by United Kingdom Accreditation Service (UKAS, registration number 8353) in accordance with the recognised International Standard ISO 15189:2012 for Medical Laboratories – requirements for quality and competence. The unit is equipped with state-of-the-art analytical equipment. Here is a link to the UKAS website showing the current scope of accreditation: https://www.ukas.com/wp-content/uploads/schedule_uploads/00007/8353%20Medical%20Single.pdf

We provide a specialist AED analytical service to the National Hospital for Neurology and Neurosurgery, University College Hospitals NHS Trust, and to many hospitals and organisation throughout the UK and from Europe.

How can the service be accessed?

The service can be accessed by referral from a GP, neurologist or other healthcare professional. For more information contact:

Epilepsy Society Chalfont Centre switchboard number: 01494 601300, Head of Unit, Prof P N Patsalos: ext 1355, Consultant Clinical Scientist/Laboratory Manager, Dr E P Spencer: ext 1423, Clinical Scientist, Mr A W James : ext 1494, Clinical Scientist, Mr F P Quinlivan: ext 1424, Main laboratory: ext 1424, Patient results and enquiries: ext 1423.

E-mail: TDM_Unit@epilepsysociety.org.uk