Objective : Carvedilol is a non-selective β blocker with an α blocking activity. Since this drug is highly fat-soluble, it can pass through the blood-brain barrier, and thus may induce depression and lower QOL. In the present study, physicians and pharmacists collaborated to evaluate the antihypertension effect of carvedilol and post-administration changes in QOL. Furthermore, the relationship between QOL and antihypertension effect was analyzed.
Design : Self-controlled study.
Patients and Methods : Subjects were outpatients with hypertension above the age of 70 years who visited one of 42 medical institutions in Japan between April 1995 and March 1996. A total of 243 patients were registered, and 10-20 mg of carvedilol was administered once a day for six months. Pharmacists assessed the QOL of these patients by asking 82 questions on three separate occasions : before administration and one and six months after administration. The antihypertensive effect of this drug was investigated in patients in whom all three QOL questionnaires were collected. The main test items were antihypertensive effect, changes in QOL (subjective QOL with a special emphasis on patient psychology), and the relationship between antihypertensive effect and QOL. The antihypertensive effect of this drug was statistically analyzed by a paired t-test, and changes in QOL were statistically analyzed using generalized estimating equations.
Results : All three QOL questionnaires were collected from a total of 146 patients. Their pre-administration systolic blood pressure was 159.6±1.4 mmHg, and diastolic blood pressure 94.0±0.9 mmHg, and their blood pressure decreased significantly one month after the start of administration. This antihypertensive effect of carvedilol persisted, and the systolic and diastolic blood pressure of these patients six months after the start of administration was 141.1±1.2 and 85.2±0.7 mmHg, respectively (significant decreases when compared to pre-administration levels ; both p<0.05).
Subjective QOL improved significantly after carvedilol administration. And, changes were not seen in sexual function. Changes in the five categories of subjective QOL were as follows : psychological stability, disease-induced inconvenience, and independence improved significantly after carvedilol administration, but changes were not seen in gratification or vitality. However, improvements in subjective QOL did not correlate with improvements in blood pressure.
Conclusions : The results of the present study showed that carvedilol improved QOL without negatively affecting sexual function. Subjective QOL reflects the psychological well-being of patients. In the present study, psychological stability, disease-induced inconvenience, and independence improved significantly, but changes were not seen in gratification or vitality. Since β blockers can suppress the central nervous system, they can reduce psychological stability, gratification and vitality. Even though carvedilol is highly fat-soluble, the results of non-clinical studies have shown that it does not suppress the central nervous system as much as propranolol. The results of the present study showed that carvedilol does not strongly suppress the central nervous system of humans. Moreover, significant changes in QOL were not seen between one and six months after the start of administration of carvedilol, suggesting that it is possible to estimate the QOL of patients on antihypertensive therapy after six months of administration by assessing their QOL one month after administration.