Different sensitivity to hydrochlorothiazide and to potassium-canrenoate among essential hypertensive patients.
We compared the response of blood pressure (BP) to either K-Canrenoate (K-Can) or hydrochlorothiazide (HCTZ) in 26 mild-to-moderate essential hypertensives in a double-blind, cross-over design over 2 months each. The dose was 12.5 mg o.d. for HCTZ and 50 mg o.d. for K-Can: dosing was doubled after 1 month if seated diastolic BP was > or = 95 mmHg. Eight pts were "selective responder" to the lowest dose of HCTZ (HCTZ-R), and 6 to K-Can (K-Can-R). Seven pts had their high blood pressure controlled by the highest dose of both drugs and 4 were insensitive to both. One pt dropped out during HCTZ for low plasma K+, and 3 during K-Can (nausea and dizziness: 2 pts; plasma creatinine rise: 1 pt). All these side effects were reverted after drug withdrawal. HCTZ-R and K-Can-R differed for PRA (1.4 +/- 0.6 vs 0.8 +/- 0.4 Ang I ng/ml/h, p < 0.05) and Na-K-Cl cotransport (230 +/- 39 vs 372 +/- 24 mumolNa/L RBC/h, p < 0.01). Our data suggest the existence of a subgroup of essential hypertensives surprisingly insensitive to HCTZ, characterized by a "low" PRA and by a Na(+)-K(+)-Cl- cotransport higher than the HCTZ-R. Their selective response to K-Can suggest a peculiar pathogenetic mechanism underlying their high blood pressure.
Hypertension Center, University of Sassari, Viale S. Pietro, Italy.
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N
Glorioso
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Melis
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Manunta
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C
Troffa
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Tonolo
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Soro
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Madeddu
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Pazzola
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Pala
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Cusi
D001794:Blood Pressure / Q000187:drug effects; D002191:Canrenoic Acid / Q000009:adverse effects / Q000627:therapeutic use*; D004311:Double-Blind Method; D004351:Drug Resistance; D005260:Female; D006801:Humans; D006852:Hydrochlorothiazide / Q000009:adverse effects / Q000627:therapeutic use*; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000097:blood
D006852:Hydrochlorothiazide; D002191:Canrenoic Acid; D011188:Potassium