Bromide as marker for drug adherence in hypertensive patients.
BACKGROUND
Insufficient drug adherence is an important reason for inadequate blood pressure control. Currently, methods that measure drug adherence objectively are lacking. Objective methods are needed to help improve blood pressure control and outcome in hypertensive patients.


CONCLUSIONS
Potassium bromide added to antihypertensive drugs can be used to monitor drug adherence in individual patients. However, although this method is objective, it is rather time-, cost- and work-consuming. AIMS Adherence to antihypertensive medication is essential for adequate long-term control of blood pressure (BP). This study investigated different methods of measuring adherence in hypertensive patients.


METHODS
Patients were included if BP was insufficiently controlled on monotherapy. After a placebo period patients were treated with trandolapril 2 mg/verapamil SR 180 mg (TV). BP was determined using a mercury sphygmomanometer and ambulatory BP monitoring. Adherence was measured by capsule counting, electronic registration of pill-box openings and by measuring serum bromide concentrations. Potassium bromide was added to each TV capsule.


RESULTS
Thirty patients participated in the study. Treatment with TV significantly lowered office BP and ambulatory BP. Results for electronic monitoring and adherence based on bromide measurements were comparable. Adherence was slightly higher when assessed by capsule counting.


CONCLUSIONS
Measuring serum bromide concentrations may be suitable for assessment of adherence to drug therapy giving comparable results to electronic monitoring. Using capsule counting, electronic monitoring and measurement of bromide concentrations, nonadherent patients were identified.
Braam
Richard L
RL
Department of Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
van Uum
Stan H M
SH
Lenders
Jacques W M
JW
Thien
Theo
T
D000293:Adolescent; D000368:Aged; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects; D001965:Bromides; D002121:Calcium Channel Blockers / Q000627:therapeutic use; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D007211:Indoles / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D017680:Potassium Compounds; D014700:Verapamil / Q000627:therapeutic use*
D000959:Antihypertensive Agents; D001965:Bromides; D002121:Calcium Channel Blockers; D007211:Indoles; D017680:Potassium Compounds; C052035:trandolapril; D014700:Verapamil; C039004:potassium bromide