Mathematical model of the time-course of essential hypertension blood pressure changes during chronic xipamide treatment.

The hypotensive effect of xipamide administered at a mean maintenance daily dose of 23.6 mg was studied in 25 essential hypertensive patients during 48 weeks. The mean changes of systolic and diastolic blood pressures in the erect and supine positions from the first week after the onset of treatment onwards were accounted for by monotonically decreasing exponential functions. The hypotensive effect of xipamide achieved clinically satisfactory mean levels within the first week of treatment. The rate of reduction of blood pressure after the first week of treatment with xipamide depended on the inverse of a time-constant, and on the difference between the pre-treatment and the final blood pressure values. In other words, the blood pressure in patients with severe hypertension reached optimal levels more quickly than in patients with moderate and mild hypertension. No statistically significant differences were found between the slopes of the blood pressure changes with time in either body position, and long-term treatment with xipamide did not lead to orthostatic hypotension.