TABLE 1.
Outcome of drug levels measured by means of a dried blood spot sampling method combined with ultra-high-performance liquid chromatography-tandem mass spectrometry to identify nonadherence to antihypertensive drugs
| Used antihypertensive drugs | Measurement 1 | Measurement 2 (3 months follow-up) | Measurement 3 (6 months follow-up) | |
| Patient A | ||||
| Blood pressure (mmHg) – average daytime ABPM | 155/108 | 141/100 | 134/91 | |
| Time between intake and sampling (h) | 21.0 | 3.3 | 3.3 | |
| Measured antihypertensive drugs and outcome measured with UPLC-MS/MS (absence of drug in blood = negative) | Amlodipinea Valsartana Hydrochlorothiazidea Spironolactone Nifedipine Losartan | Negative Negative Negative Positive Positive – | – – Positive Positive Positive Positive | – – Positive Positive Positive Positive |
| Patient B | ||||
| Blood pressure (mmHg) – average daytime ABPM | 163/107 | |||
| Time between intake and sampling (h) | 2.0 (nifedipine) 22.0 | |||
| Measured antihypertensive drugs and outcome measured with UPLC-MS/MS (absence of drug in blood = negative) | Irbesartana Hydrochlorothiazidea Spironolactone Nifedipine | Negative Negative Negative Negative | Lost to follow-up | Lost to follow-up |
| Patient C | ||||
| Blood pressure (mmHg) – average daytime ABPM, heartrate (BPM) | 168/101, 95 | 128/101, 97 | 139/83, 88 | |
| Time between intake and sampling (h) | 16.5 | 7.0 | 1.0 | |
| Measured antihypertensive drugs and outcome measured with UPLC-MS/MS (absence of drug in blood = negative) | Hydrochlorothiazidea Losartan Metoprolol Amiloridea | Positive Positive Negative – | Positive Positive Negative Positive | Positive Positive Negative Positive |
ABPM, ambulatory blood pressure measurement; BPM, beats per minute; UPLC-MS/MS, ultra-high-performance liquid chromatography-tandem mass spectrometry.
a
Used in a single pill combination.