Kenneth Raymond

Beta-blockade in heart failure: A comparison of carvedilol with metoprolol

OBJECTIVES This study was performed to compare the long-term clinical efficacy of treatment with metoprolol versus carvedilol in patients with chronic heart failure. BACKGROUND Beta-adrenergic blockade is of proven value in chronic heart failure. Metoprolol, a selective beta-blocker, is widely used, but recent trials suggest carvedilol, a nonselective beta-blocker with alpha-1-receptor antagonist activity and antioxidant activities, is also effective. It is uncertain, however, if these additional properties of carvedilol provide further clinical benefit compared with metoprolol. METHODS In this randomized double-blind control trial, 51 patients with chronic heart failure and mean left ventricular (LV) ejection fraction of 26% +/- 1.8% were randomly assigned treatment with metoprolol 50 mg twice daily or carvedilol 25 mg twice daily in addition to standard therapy after a four-week dose titration period for a total of 12 weeks. Response was assessed by a quality of life questionnaire, New York Heart Association class, exercise capacity (6-min walk test), radionucleotide ventriculography for LV ejection fraction, two-dimensional echocardiography measurement of LV dimensions and diastolic filling and 24-h electrocardiograph monitoring to assess heart rate variability. RESULTS Both carvedilol and metoprolol produced highly significant improvement in symptoms (p < 0.001), exercise capacity (p < 0.05) and LV ejection fraction (p < 0.001), and there were no significant differences between the two drugs. Carvedilol had a significantly greater effect on sitting and standing blood pressure, LV end-diastolic dimension and normalized the mitral E wave deceleration time. CONCLUSIONS Both metoprolol and carvedilol were equally effective in improving symptoms, quality of life, exercise capacity and LV ejection fraction, although carvedilol lowers blood pressure more than metoprolol.

Pharmacists' Attitudes toward Adverse Drug Reaction Reporting in Hong Kong

OBJECTIVE: To study the attitudes and knowledge of pharmacists in Hong Kong toward the reporting of adverse drug reactions (ADRs). METHODS: In December 1993, all pharmacists who were working in retail shops (n=230), hospitals (n=44), or outpatient clinics (n=12) in Hong Kong were sent a questionnaire as well as a letter explaining the purpose of the survey. RESULTS: One hundred and twenty-nine pharmacists (retail pharmacies 40.4 percent, hospitals 68.2 percent, outpatient clinics 50 percent) responded. Although 93 percent of the pharmacists in this survey agreed that it is necessary to report ADRs, a much smaller proportion (14.7 percent) had actually done so in the previous 12 months. Most pharmacists (87.4 percent) were not aware of any ADR reporting system in Hong Kong. There did not appear to be a relationship between ADR reporting and the length or place of practice, workload, or patient contact time. Severe or unusual ADRs and ADRs to new products were perceived to be significant enough to report. CONCLUSIONS: The great majority of pharmacists in Hong Kong agreed on the necessity of reporting ADRs. The lack of knowledge of an ADR reporting program might have led to nonreporting in the past. It is important that there be continuing efforts to promote ADR reporting programs.

Utilization and Monitoring of Aminoglycosides in Oncology Patients at a Hong Kong Government Hospital

1. Fabre G, Julian B, Saint-Aubert B, Joyeux H, Berger Y. Evidence for CYP3A-mediated N-deethylation of amiodarone in human liver microsomal fractions. Drug Metab Dispos 1993;21:978-85. 2. Chow MSS. Intravenous amiodarone: pharmacology, pharmacokinetics, and clinical use. Ann Pharmacother 1996;30:637-43. 3. Andreasen F, Agerbaek H, Bjerregaard P, Grotzche H. Pharmacokinetics of amiodarone after intravenous and oral administration. Eur J Clin Pharmacol 1981;19:293-9. 4. Burger DM, Hoetelmans RMW, Koopmans PP, Meenhorst PL, Mulder JW, Hekster YA, et al. Clinically relevant drug interactions with antiretroviral agents. Antiviral Therapy 1997;2:149-65. 5. Product information. Norvir (ritonavir). Chicago: Abbott Laboratories, 1996.

Use of indapamide in hospital and community clinics and its effect on plasma potassium in Chinese patients

Objectives: To investigate the usage pattern of indapamide and other antihypertensive drugs in patients attending a community‐based government outpatient clinic (GOPC) or a hospital‐based specialist clinic (SC). The plasma potassium concentrations of patients receiving indapamide and other diuretics were also examined. Method: Prescriptions from the SC and the GOPC were reviewed and collected during January 1998. Patients’ plasma potassium concentrations and the date of initiation of each medication were retrieved from the hospital computer databases at SC. An age‐ and sex‐matched control group of patients on non‐diuretic antihypertensive drugs was identified. Results: A total of 1648 and 773 prescriptions were collected from the SC during a 1‐week period and GOPC during a 1‐month period, respectively. Approximately half (45%) of the patients received antihypertensive treatment. Indapamide was five times more frequently prescribed in GOPC than SC (84·7 vs. 17·7%, P<0·001). Calcium channel blocking agents were the commonest antihypertensive drugs used in both clinics. The mean plasma potassium concentration of patients taking indapamide was lower than that of the control group ( P=0·037). Multiple linear regression analysis showed that consumption of indapamide ( P=0·002) and duration of diuretic therapy (P=0·023) were significantly related to changes in plasma potassium concentrations [multiple regression equation for potassium level=4·09−0·145 (thiazide=1)−0·377 (indapamide=1) −0·00468 (duration of diuretic therapy in months)]. Conclusion: Indapamide was used extensively in the community clinic and less in the hospital‐based outpatient clinic. Patients receiving indapamide had a significantly lower plasma potassium concentration as compared to other diuretics or antihypertensive groups and this was predicted by a multiple linear regression model. Monitoring plasma electrolytes before initiation of indapamide treatment and at regular intervals thereafter is essential for detecting the hypokalaemia that may occur in Chinese patients.

Evaluation of Losartan Usage in a Regional Hospital in Hong Kong

Objective: To determine whether losartan usage follows the hospitals guidelines in terms of indications and reasons for use and to assess the accuracy of physicians in completing the losartan usage monitoring forms. Design: Drug utilization survey. Setting: A major government hospital in Hong Kong. Participants: Inpatients or outpatients prescribed losartan for the first time. Intervention: Physicians were to complete a monitoring form with both indications and reasons for losartan use. Main Outcome Measures: The appropriateness of losartan prescribing was evaluated in terms of indications (for hypertension with impaired left-ventricular function or hypertension in diabetic patients with persistent proteinuria) and reasons for preferred use (previous intolerance to adverse effects of angiotensin-converting enzyme inhibitors). The accuracy of completed monitoring forms was also assessed. Results: Forty-eight patients were prescribed losartan since its addition to the hospital formulary through the end of the study period (September 1997-May 1998). A review of medical records (regardless of the information provided by the physicians on the monitoring forms) revealed that 39 patients (81.3%) were prescribed losartan for appropriate indications and that 22 (45.8%) were given losartan rather than angiotensin-converting enzyme inhibitors for appropriate reasons according to the guidelines. Both appropriate indications and reasons were met in only 15 patients (31.3%). Of the 48 monitoring forms that were collected, three (6.3%) were not completed. The concordance rate of information provided by the doctors and information from case notes was 61.5% for indications and 34.8% for reasons of preferred use. Conclusions: Adherence to the hospitals usage guidelines and accuracy of the monitoring forms were suboptimal. Considering the high cost of losartan and its potential for long-term use, more educational activities, better dissemination of information, and more frequent evaluation of the acceptability of recommended usage guidelines are warranted.