BackTherapeutic drug monitoring of anticonvulsants
Therapeutic drug monitoring is used in the selection of an individual dose and frequency of medication for each patient. Pharmacokinetic data have been used primarily in epileptology – knowledge of the pharmacokinetic properties of anticonvulsants is important for optimizing treatment, since the action of drugs depends on the concentration of the active drug in the brain.
The determination of anticonvulsants in the blood is one of the main requirements of international standards for the management of patients with epilepsy. Therapeutic drug monitoring makes it possible to determine the qualitative aspects of changes in drug elimination due to the patient's fault, normally due to a disease or violation of physiological conditions. The selection of medication based only on clinical data is difficult, and insufficient treatment can lead to serious consequences for the patient.
There are many reasons for using therapeutic drug monitoring to correct the individual treatment of epilepsy patients. It is important to know the concentration of anticonvulsants in the following cases:
- if the drug is ineffective when taken in therapeutic doses;
- when signs of intoxication appear;
- in problematic cases with special physiological or pathological conditions;
- during pregnancy (the pharmacokinetics of AED) may change due to various physiological processes: decreased absorption, impaired distribution and decreased binding to proteins, increased metabolism due to increased activity of treatment enzymes, increased elimination drugs.
In the elderly, the clearance of most AED is reduced by an average of 30 to 50%. In the elderly, pronounced physiological changes are detected, such as decreased absorption, impaired distribution, decreased activity of metabolic enzymes and changes in blood flow to the eliminating organs, slowing kidney function, affecting pharmacokinetic parameters. Infants and young children belong to a special population, which differs from adults by a rapid change in pharmacokinetics. In young children, especially from six months to six years, the half-life of most anticonvulsants is reduced, and the volume of distribution may be higher than in adults. In some drug interactions: anticonvulsant preparations with antihypertensive drugs, anticoagulants and antiplatelet agents, oral contraceptives, analgesics, NSAID. Knowledge of possible drug interactions is a prerequisite for the use of AED.
Today, the OLYMP laboratory branches monitors valproic acid preparations – Depakin, Convulex. This group of drugs has proven itself well, especially in children's practice. Tests to determine the concentration of valproates in the blood do not require special preparation and are performed on an empty stomach.