Fixed-dose versus separate drug combinations for antihypertensive treatment: literature review.
BACKGROUND
Hypertension requires effective interventions to reduce cardiovascular morbidity and mortality. Drug therapies have achieved optimal blood pressure levels in affected patients. Recent clinical guidelines suggest drug combinations a fact that has led to the development of various fixed-dose combinations.


OBJECTIVE
To find the best available evidence about the effectiveness of antihypertensive drugs in fixed-dose combinations compared with separate dose combinations for blood pressure control, treatment adherence and reducing cardiovascular morbidity and mortality.


METHODS
Systematic literature search of the best evidence available in the following databases was performed: MEDLINE/PubMed, LILACS, Cochrane and institutional publications of WHO and PAHO.


RESULTS
Two meta-analyses comparing the two combinations were found, in both studies medication compliance was evaluated, no control of blood pressure or effects on cardiovascular events was assessed. Both studies are of very low quality of evidence due to limitations in search methodology, suboptimal quality of the included studies and heterogeneity of the analyzed variables. WHO drug use policies for antihypertensive drugs do not suggest fixed-drug combinations. These combinations are not included in Chile´s national drug formulary.


CONCLUSIONS
Well-designed studies are required to demonstrate the effectiveness of antihypertensive drugs in fixed-dose combination compared with separate dose combinations for controlling blood pressure, treatment adherence and reducing cardiovascular morbidity and mortality.
Subdirección Médica, Servicio de Salud Araucanía Sur, Temuco, Chile. Address: Subdirección Médica, Servicio de Salud Araucanía Sur, Prat 969, Temuco, Chile. Email: josecallejar@hotmail.com.
José Luis
JL
Calleja Rivero
Subdirección Médica, Servicio de Salud Araucanía Sur, Temuco, Chile.
Franklin
F
Zerpa
Subdirección Médica, Servicio de Salud Araucanía Sur, Temuco, Chile.
Loreto
L
Rivera
 antihypertensive drugs;  fixed-dose combinations;  hypertension; drug combinations