Therapeutic Drug Monitoring of escitalopram: Influence by age, gender, body weight, BMI, smoking, caffeine and comedication with a special focus on interactions with mirtazapine and statins

The analysis resorts to KONBEST, a database filled with patients' TDM data. Initiated in 2005 1727 probes on medication with escitalopram have been gathered until January 2018. The population is most applicable to search for particularities applying to everyday patients as it contains a naturalistic sample.

1642 probes containing full information as for age, gender, prescribed dose, concentration and comedication are retrospectively evaluated. The mean age of the population is 47.27 ± 15.52 (range 18 – 91) with a proportion of 62% women. 244 probes are drawn from patients older than 65 years. Drug concentrations range from 0 ng/ml to a maximum of 462 ng/ml, whereas the highest values have been found in the older patients. 19% of the latter exceed 80 ng/ml defined as the top level of therapeutic reference range. After the warning by Lundbeck in December 2011 the proportion of doses above 20 mg/d decreased from 44% to 19%. Nevertheless it is the drug concentration not the dosage causing both desired and adverse effects. Concentrations resulting of one dose vary about a 20fold factor in average when only including the midst 95% data. The dose related concentration as a pharmacokinetic parameter (median, 95% CI) therefore is correlated with the age at blood withdrawal clarifying that the elimination impairs with age (18 – 35: 1.00 ± 0.15; ≥65 1.70 ± 0.27). The impact of gender (w: 1.33 ± 0.11; m: 1.17 ± 0.11), smoking (yes: 1.15 ± 0.14; no: 1.33 ± 0.13), caffeine (yes: 1.28 ± 0.11; no: 1.14 ± 0.21), mirtazapine (yes: 1.10 ± 0.14; no: 1.30 ± 0.10) and statins (yes: 1.48 ± 0.69; no: 1.25 ± 0.08), especially simvastatin (yes: 1.78 ± 0.71), is to be statistically verified for covariates.