title: Treatment with beta-blockers--the value of an even plasma concentration over 24 h.
abstract: The aim of this paper was to examine if there were clinical studies supporting a beneficial effect of an even plasma concentration over 24 h for the most frequently prescribed beta 1-blockers in clinical practice, metoprolol CR/ZOK and atenolol. There are several studies showing that metoprolol CR/ZOK has a more even plasma concentration compared with atenolol and conventional metoprolol tablets when administered once daily. There are also studies showing that metoprolol CR/ZOK produces a more even beta 1-blockade over 24 h. This is determined by expressing the percentage reduction in exercise heart rate in relation to placebo at intervals throughout the 24-h period and comparing the results with those of atenolol and conventional metoprolol tablets. Clinical studies indicate that the low peak plasma concentration produced by metoprolol CR/ZOK leads to more beta 1 selectivity than atenolol and conventional metoprolol tablets. The loss of beta 1 selectivity at peak plasma concentrations may cause unwanted side-effects. The peak plasma concentration of atenolol coincides with increased general and leg fatigue, problems less evident when patients are on metoprolol CR/ZOK. The frequency and severity of other central nervous system related side-effects are comparable with metoprolol CR/ZOK and atenolol. In conclusion, there are several clinical studies supporting a beneficial effect of the even plasma concentration over 24 h achieved with metoprolol CR/ZOK.
authors.affiliation: Department of Internal Medicine, Sahlgrenska University Hospital, Göteborg University, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Agewall
authors.forename: M
authors.initials: M
authors.lastname: Kendall
mesh_terms: D000284:Administration, Oral; D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage / Q000097:blood* / Q000627:therapeutic use*; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000097:blood* / Q000627:therapeutic use*; D001262:Atenolol / Q000008:administration & dosage / Q000097:blood* / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects; D018849:Controlled Clinical Trials as Topic; D005080:Exercise Test; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000188:drug therapy; D008790:Metoprolol / Q000008:administration & dosage / Q000097:blood* / Q000627:therapeutic use*
chemical_list: D000319:Adrenergic beta-Antagonists; D000959:Antihypertensive Agents; D001262:Atenolol; D008790:Metoprolol