Blood pressure lowering efficacy of diuretics as second-line therapy for primary hypertension

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.