Therapeutic drug monitoring of valproic acid through plasma concentration

Jakjimoska, Verica and Gjorgjeska, Biljana (2020) Therapeutic drug monitoring of valproic acid through plasma concentration. Macedonian Pharmaceutical Bulletin, 66 (1). pp. 5-6. ISSN 1857 - 8969

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Therapeutic drug monitoring is the measurement
of specific drug and/or their breakdown products
(metabolites) at timed intervals to maintain a
relatively constant concentration of the medication
in the blood. Some of the monitored drugs tend to
have a narrow “therapeutic index”, which is a ratio
between the toxic and therapeutic (effective) dose of
Burtn et al. (2006) have shown that valproic acid
is an 8-carbon 2-chain fatty acid that is metabolized
by the liver and processed at a variable rate based on
the patient’s liver function and age, in addition to
patient’s other routine medications with which
valproic acid may interact. At therapeutic
concentrations, valproic acid mediates prolonged
recovery of voltage-activated Na+ channels, thereby
inhibiting repetitive firing induced by depolarization
of cortical and spinal cord neurons.
Unborn babies exposed to valproate are at very
high risk of neurodevelopment disability and other
birth defects and the need for effective contraception
planning must also be emphasized, along with the
requirement for specialist oversight to safely change
their medication if planning a pregnancy according
toMarshall and Bangert (2008).
The determination of an antiepileptic drug
concentration is recommended as a baseline
measurement after starting drug therapy, according
to NICE Clinical Guideline 137 (2020), after a
change in the drug dose regimen, after addition of a
second drug that may interact with the antiepileptic
drug, and after a change in the patient’s liver,
cardiac, or gastrointestinal function.According to
NICE Clinical Guideline 38 (2020), measurement of
an antiepileptic drug concentration is usually
performed after 4 to 5 elimination half-lives of drug
administration, that is, once a steady state
concentration has been achieved.

Item Type: Article
Subjects: Medical and Health Sciences > Basic medicine
Medical and Health Sciences > Clinical medicine
Medical and Health Sciences > Health sciences
Medical and Health Sciences > Other medical sciences
Divisions: Faculty of Medical Science
Depositing User: Biljana Gorgeska
Date Deposited: 25 Jan 2021 10:52
Last Modified: 25 Jan 2021 10:52

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