Therapeutic drug monitoring of gabapentin in various indications

Abstract

Objectives Gabapentin has been increasingly used in various indications in recent years. Despite variable pharmacokinetics, therapeutic drug monitoring (TDM) is scarcely described in other indications than epilepsy. The aim of the study was to investigate the use and pharmacokinetic variability of gabapentin in epilepsy and non‐epilepsy indications and to further evaluate the use of TDM in patients with restless legs syndrome (RLS). Materials & Methods Population‐based data from the Norwegian Prescription Database, retrospective TDM data from the section for Clinical Pharmacology, the National Center for Epilepsy, Norway, and prospective observational data on patients with RLS were used. Results The use of gabapentin increased by 30% from 2014 to 2017 (32 181 to 42 675 users). TDM data from 120 patients showed a 22‐fold pharmacokinetic variability in concentration/dose ratios, and this ratio was elevated in elderly patients (≥65 years). The majority of elderly used gabapentin for non‐epilepsy indications. In patients with RLS, intake in the evening/night only was common due to nocturnal symptoms, in contrast to regular dosing regimens in epilepsy. Thus, drug fasting concentrations do not reflect concentrations at the time of required therapeutic effect. TDM was still found useful in most patients to support dosage increase or evaluate adverse effects. Conclusion Due to extensive pharmacokinetic variability, TDM can benefit patients using gabapentin. Challenges with applying TDM in new indications such as RLS include different dosage regimens and consequently different interpretation of serum concentrations. Thus, TDM should be requested on clear clinical grounds and the service tailored according to the therapeutic indication.

Pharmacological aspects of antiseizure medications: From basic mechanisms to clinical considerations of drug interactions and use of therapeutic drug monitoring

“…In recent years several new ASMs have been introduced to the market, and around 30 different drugs are available internationally 1–3 . The armamentarium of drugs to choose from helps to tailor the treatment for groups and individuals with epilepsy and also in other disorders, that is, psychiatry and pain management 3–7 . Pharmacological challenges with all these drugs are numerous and therefore warrant detailed knowledge of the pharmacodynamic and pharmacokinetic properties of the drugs.…”

Second Generation of Antiepileptic Drugs and Oxidative Stress

“…GBP is recommended against partial epilepsy with/without secondary generalization and can be used in patients over three years of age. In addition, it may be used for neuropathic pain, restless legs syndrome, fibromyalgia, trigeminal neuralgia, multiple sclerosis, headache, anxiety, and post-operative pain [ 39 ]. In general, GBP is well tolerated and its few adverse effects include somnolence (in 19% of patients), dizziness (17%), ataxia (13%), fatigue (11%), nystagmus (8%) and headache (8%).…”

Design and Production of DNA-Based Electrochemical and Biological Biosensors for the Detection and Measurement of Gabapentin Medication in Clinical Specimens

“…9 Hence, TDM must be used to find whether the patient's poor response to increasing drug dose causes disorder in absorption or not. 17 The importance of nanocomposites and nanoparticles in the manufacture of electrochemical sensors is very important, especially in the fields of medicine, pharmacy, and energy. For example, a study demonstrated that EGT biosensors could be extended with changing enzymes or nanomaterials, or hybrid nanomaterials for specific analyte detection.…”