The effect was similar to that obtained when thiazides are used as a single agent .
Thiazides when given as a second-line drug have a dose related effect to lower blood pressure that is similar to when they are added as a first-line drug .
This means that the BP lowering effect of thiazides is additive .
Loop diuretics appear to have a similar blood pressure lowering effect as thiazides at 1 times the recommended starting dose .
Because of the short duration of the trials and lack of reporting of adverse events , this review does not provide a good estimate of the incidence of adverse effects of diuretics given as a second-line drug
BACKGROUND Diuretics are widely prescribed for hypertension not only as a first-line drug but also as a second-line drug .
Therefore , it is essential to determine the effects of diuretics on blood pressure ( BP ) , heart rate and withdrawals due to adverse effects ( WDAEs ) when given as a second-line drug .
The results of a large multicentre study comparing low-dose lisinopril-hydrochlorothiazide with the monocomponents.
The efficacy , tolerability and metabolic effects of a fixed combination of lisinopril 10 mg and hydrochlorothiazide 12.5 mg ( L/HCTZ ) and those of the monocomponents were compared in 286 mild to moderate hypertensive patients in a 17-centre study using a double-blind , r and omized , parallel-group design . After 2 weeks of placebo run-in , patients were r and omized to one of the three treatments for 8 weeks . Supine and st and ing BPs were measured at peak blood levels ( 4 - 8 hours post dose ) after 4 weeks , and at trough blood levels ( 24 - 28 hours post dose ) after 8 weeks . The BP reduction from baseline was greater with L/HCTZ than with the monocomponents at weeks 4 and 8 ; at week 8 the reduction was statistically significant vs lisinopril for st and ing DBP ( P less than 0.027 ) but not for st and ing SBP ; the reduction was significant with L/HCTZ vs hydrochlorothiazide at week 4 [ P = 0.0002/0.0001 ( SBP/DBP ) supine ; P = 0.0002/0.0002 st and ing ] and at week 8 ( P = 0.0001/0.0001 supine and st and ing ) . Response at week 8 ( supine DBP less than or equal to 90 mm Hg ) with L/HCTZ ( 87.0 % ) was greater than with hydrochlorothiazide ( 29.0 % ; P less than 0.0001 ) and marginally greater than with lisinopril ( 74.2 % ; P = 0.069 ) . Heart rate fell statistically significantly more with L/HCTZ ( by 3.3 beats/minute ) than with HCTZ ( by 0.86 beats/minute ; P = 0.018 ) . L/HCTZ treatment significantly increased plasma uric acid levels compared with lisinopril . L/HCTZ decreased potassium , while lisinopril  increased potassium . L/HCTZ decreased cholesterol ; HCTZ increased it . Adverse effects were more common on L/HCTZ vs lisinopril ( P = 0.033 ) but not vs hydrochlorothiazide . ( ABSTRACT TRUNCATED AT 250 WORDS
The effect was similar to that obtained when thiazides are used as a single agent .
Thiazides when given as a second-line drug have a dose related effect to lower blood pressure that is similar to when they are added as a first-line drug .
This means that the BP lowering effect of thiazides is additive .
Loop diuretics appear to have a similar blood pressure lowering effect as thiazides at 1 times the recommended starting dose .
Because of the short duration of the trials and lack of reporting of adverse events , this review does not provide a good estimate of the incidence of adverse effects of diuretics given as a second-line drug
BACKGROUND Diuretics are widely prescribed for hypertension not only as a first-line drug but also as a second-line drug .
Therefore , it is essential to determine the effects of diuretics on blood pressure ( BP ) , heart rate and withdrawals due to adverse effects ( WDAEs ) when given as a second-line drug .