OBJECTIVE: To perform a systematic review of the literature pertaining to the efficacy of amlodipine monotherapy in reducing systolic blood pressure (SBP) in a variety of patient subgroups. The sixth report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI) recommends diuretics or long-acting dihydropyridine calcium channel blockers (CCBs) for the treatment of isolated systolic hypertension (ISH). Amlodipine is the most commonly prescribed CCB worldwide; therefore, a systematic review was performed to capture the impact of amlodipine monotherapy on SBP. METHODS: Following a protocol that had been developed a priori, published literature in 5 languages was searched from 1980 to 2001, using 3 electronic databases and manual bibliography checks of recent review articles and all accepted studies. Randomized controlled trials with at least 10 patients, one treatment arm of amlodipine monotherapy, minimum treatment duration of 8 weeks, reporting baseline and endpoint BP, and presence of baseline hypertension (defined as SBP = 140 mm Hg, diastolic blood pressure (DBP) = 90 mm Hg, or both) were accepted for this systematic review. RESULTS: A total of 696 citations were reviewed, of which 85 met all inclusion criteria. Comparable treatment arms were pooled, and weighted means of efficacy results were calculated. In the amlodipine monotherapy arms, representing over 5,000 patients treated with the drug, amlodipine reduced SBP by an average of 17.5 mm Hg from baseline (an estimated 13.3 mm Hg more than placebo). The effect of amlodipine in reducing SBP was even more marked in elderly patients (24.1 mm Hg mean reduction), black patients (23.9 mm Hg mean reduction), and patients with ISH (25.9 mm Hg mean reduction), although the number of studies investigating these special populations was small. CONCLUSION: Amlodipine is effective for reducing SBP. Long-term trials are needed to correlate SBP reduction with clinical outcomes.