Chronic treatment with tibalosine in essential hypertension

After a run-in period on placebo, 26 patients with essential hypertension were prescribed single-blind tibalosine, 150 mg daily. On tibalosine their blood pressure decreased from 157/101 to 147/93 mm Hg (p less than 0.001) and their heart rate from 74 to 68 beats per minute (p less than 0.01), while plasma renin activity tended to fall from 0.81 to 0.65 ng/ml/hr (p = 0.06). Twelve patients, maintained on monotherapy with tibalosine for an average of 3.8 months, kept a diastolic pressure below 90 mm Hg. Ten patients, whose diastolic pressure on tibalosine alone remained equal to or higher than 90 mm Hg were continued on this drug for 6.6 months, but were additionally given in a double-blind and randomized way either placebo, or atenolol 100 mg, or chlorthalidone, 50 mg, daily. As compared to tibalosine plus placebo, blood pressure and heart rate decreased further on tibalosine plus atenolol from 148/97 to 140/90 mm Hg (p less than 0.05) and from 70 to 60 beats per minute (p less than 0.05), respectively. The additional blood pressure lowering effect of tibalosine plus chlorthalidone to a level of 143/96 mm Hg was not statistically significant. Eight of 10 patients' blood pressure responded better to tibalosine combined with atenolol than with chlorthalidone. Because of adverse reactions tibalosine was discontinued in 8 of the 26 patients (31%), namely in 4 who prematurely dropped out from the study and in another 4 patients, who remained adherent to the protocol. Somnolence, weary legs and dry mouth were reported more frequently (p less than 0.05) on tibalosine than on placebo.

tibalosine is an effective anti-hypertensive drug, but side effects preclude its clinical use at a daily dose of 150 mg; the combination with a beta-adrenoceptor blocking drug seems therapeutically more effective than with a thiazide.