[Assessment for antihypertensive drug intake: How, where and when?]

Hypertension is a public health problem managed according to therapeutic strategies published in France by the Hauteautoritéde santé (HAS - French Health Authorities). For patients with resistant hypertension, related or not to a non-adherence, prescribers need to be sure the exposure is high enough to achieve the tensional target. Quantitative analysis of antihypertensive drugs in different biological matrices (blood/urine) is one possible solution. However, this involves determining the concentrations observed at standard doses and knowing how to interpret the measured concentrations. It is also necessary to identify medical laboratories that can assay antihypertensive drugs. This was the aim of our work.

The main antihypertensive drugs recommended by the HAS have been listed. For each of them, we looked for published steady-state plasma/serum concentrations and quantities excreted in the urine at usual dosages. In addition, the elimination half-life and linear pharmacokinetic profile were specified for each antihypertensive agent measured in plasma/serum. Pharmacology-Toxicology laboratories in France likely to carry out assays were identified. The time taken to report the result and the cost of the analysis were also specified.

All of the afore-mentioned information has been collected and presented in a table. This can then be used to compare the plasma/serum concentration or the quantity measured in a patient's urine with the values reported in the literature. In cases where the blood sampling times differ between those of the patient and the published data, the patient's measured value is compared to the estimated value based on the published concentrations and pharmacokinetics.

Interpretation of the plasma/serum/urinary value measured or estimated for an antihypertensive drug is a particularly interesting approach to determine if drug exposure is enough and a possible non-adherence. However, this activity is mostly carried out in hospital centres.