Synergistic decrease in blood pressure by captopril combined with losartan in spontaneous hypertensive rats
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- Shin, CY., Choi, WS., Yi, I. et al. Arch. Pharm. Res. (2009) 32: 955. doi:10.1007/s12272-009-1619-x
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This study was designed to examine the anti-hypertensive effect of the combination therapy of captopril with losartan by oral administration using both independent and cross-over experimental protocols. In independent experimental protocols, four different groups of spontaneous hypertensive rats (SHR) were treated for 1 or 2 weeks: control, captopril (20 mg/kg/day), losartan (20 mg/kg/day), and combination captopril (10 mg/kg/day) with losartan (10 mg/kg/day). In cross-over protocols, each SHR received all four treatments for 1 or 3 days with an interval of several days between each injection for washing-out and return to high blood pressure (BP) levels. BP and heart rate (HR) were measured in conscious telemetered SHR. According to the results from the independent protocol, regardless of a 1- or 2-week administration period, combination therapy with low doses of captopril and losartan had a greater anti-hypertensive effect than individual high-dose monotherapy. Similarly, results from the cross-over protocol showed that regardless of 1-day or 3-day administration, the decrease in BP in the 11th and 12th hour after administration was greatest with the combination of low-dose captopril and losartan. Therefore, combination therapy with low doses of captopril with losartan lowered BP to a greater extent than a high dose of either individual monotherapy.