VyjádĹ™enĂ k pouĹľĂvánĂ hmotnostnĂ koncentrace v pĹ™ĂpadÄ›
terapeutického monitorovánà léčiv.
Diskuze na tĂ©ma pouĹľĂvánĂ
hmotnostnĂ ÄŤi látkovĂ© koncentrace v pĹ™ĂpadÄ› terapeutickĂ©ho monitorovánĂ
lĂ©ÄŤiv probÄ›hla celosvÄ›tovÄ› v 90-tĂ˝ch letech minulĂ©ho stoletĂ
s výsledkem preferovat koncentrace hmotnostnà a to mg/l nebo µg/l. Důvodem
je předpis dávky většiny léčiv v miligramech.
Jako pĹ™Ăklad lze uvĂ©st
citaci: „The standardisation of units for
drug concentration measurement in clinical medicine is an urgent necessity.
Mass units should be retained and proposals for the adoption of molar units
should be abandoned. Prescott LF et al. Who needs molar units
for drugs? Lancet 1987 May
16;1(8542):1127-9.“
Výjimky
z tohoto pravidla jsou velice názorně shrnuty v publikaci
australských autorů: „Mass units should be used for reporting
therapeutic drug concentrations
in Australia and New Zealand; and the litre (L) should be used as the
denominator when expressing concentration. Examples of these units are mg/L and μg/L.
Exceptions to these principles include: drugs for which there is current
uniformity of reporting and supporting information using molar units, notably lithium (mmol/L) and
methotrexate (μmol/L); drugs that are also present as endogenous
substances, where the units used routinely should continue to
be used. This applies to many substances, including minerals (eg, iron;
μmol/L), vitamins (eg, vitamin D; nmol/L) and hormones (eg, thyroxine;
pmol/L); drugs for which the denominator is not a 198 of fluid and there is
international uniformity of reporting (eg, thiopurine metabolites; per 109 red
blood cells). These recommendations relate to drugs that are used
therapeutically, whether measured for therapeutic drug monitoring purposes or for assessment
of overdose. Jones GR et al. Mass or molar?
Recommendations for reporting concentrations of therapeutic drugs.
Med J Aust. 2013 Apr 15;198(7):368-9.“
Doc. MUDr. Ivana KacĂĹ™ová, Ph.D.
Předseda České společnosti klinické
farmakologie ÄŚLS JEP