Clinical Briefs

By Louis Kuritzky, MD, Clinical Assistant Professor, University of Florida, Gainesville. Dr. Kuritzky is a consultant for GlaxoSmithKline and is on the speaker's bureau of GlaxoSmithKline, 3M, Wyeth-Ayerst, Pfizer, Novartis, Bristol-Myers Squibb, AstraZeneca, Jones Pharma, and Boehringer Ingelheim.

What is the Relationship Between Gatifloxacin and Glucose Changes?

Quinolones have become some of the most popularly prescribed antibiotics in the United States. They are characteristically well tolerated and functional in a diversity of tissue compartments, although we have lost a few quinolones due to specific toxicities (such as the hepatotoxicity exhibited by trovafloxacin).

Case reports of hyperglycemia associated with gatifloxacin (GAT) have prompted further evaluation. Physiologically, GAT has the potential to produce either hyper- or hypoglycemia: animal studies indicate a potential to enhance insulin release (hence hypoglycemia), and alterations in beta cell function have been associated with hyperglycemia.

The authors looked at two separate populations of persons with abnormal glucose excursions within 30 days of receiving a new antibiotic prescription: subjects with hypoglycemia (n = 788) and a separate population (n =470) with hyperglycemia. Compared with macrolide antibiotics, GAT was associated with a statistically significant fourfold increased odds ratio for risk of hypoglycemia, and a 16 times increased odds ratio for hyperglycemia. Clinicians who prescribe GAT should be vigilant for variations in glucose, and advise patients to be similarly observant. In the event of untoward glucose impact from GAT, because other quinolones have similar efficacy profile (without attendant glucose changes), substitution may be appropriate.

Park-Wyllie LY, et al. N Engl J Med. 2006;354:1352-1361.

Altering the Course of Chronic Hepatitis B

The presence of hepatitis e antigen (HEA) for prolonged periods is characteristic of chronic hepatitis B. The consequences of chronic hepatitis B include an increased risk of hepatic carcinoma, as well as progressive liver disease. The currently available agents to treat chronic hepatitis B include interferon alfa, lamivudine, pegylated interferon alfa-2a, adefovir dipivoxil, and entecavir (EVR). Unfortunately, some of the existing agents have substantial limitations; for instance the efficacy of interferon alfa is 40% or less. Lamivudine (LAM) does result in histologic hepatic improvement in more than 50% of recipients, but less than 20% of patients enjoy suppressed viral replication, and lamivudine resistance has emerged in as many as 70% of cases.

Animal studies have indicated that EVR effectively inhibits production of Hepatitis B DNA. Indeed, in these animal models, the incidence of hepatic cancer and survival were both favorably impacted. Chang et al have compared EVR with LAM in more than 700 subjects with hepatitis C. End points included attaining an undetectable hepatitis B DNA level, changes in hepatic histology, and conversion from e antigen positive to negative.

For all 3 end points, EVR was found to be superior to LAM. Additionally, there was no evidence of emergence of EVR viral resistance, and there was no major difference in adverse effect profile between the two agents. EVR may be considered an appropriate primary therapy for e-antigen positive chronic hepatitis B patients.

Chang TT, et al. N Engl J Med. 2006;354:1001-1010.

Does Home Blood Pressure Monitoring Improve Adherence?

The latest reports from the National Health and Nutrition Surveys (NHANES) indicate that less than 40% of hypertensive patients are aware of their condition, if they are being treated, or if they are controlled to BP < 140/90. Amongst the factors which affect compliance is the use of self-monitoring. Although individual reports of home blood pressure monitoring (HBPM) have generally been favorable, this is the first systematic review of randomized controlled trials that addressed HBPM and adherence.

Eleven trials satisfied all predefined inclusion criteria, comprising over 1500 subjects. Adherence was monitored with a variety of tools: self report, pill count, and electronic monitoring devices. Over half of the trials demonstrated statistically significant improvement in medication adherence that was attributed to HBPM, however 9 of the 11 trials reviewed employed what were termed complex interventions: in addition to HBPM, subjects met with case managers and patient counselors who provided them with personal support and behavioral tips to enhance lifestyle issues favorable in hypertension.

Only in studies utilizing electronic devices or pill counts to monitor adherence (as opposed to self report) was HBPM was found to enhance compliance. HBPM may enhance compliance when coupled with appropriate adherence monitoring.

Ogedegbe G, et al. J Clin Hypertens (Greenwich). 2006;8:174-180.