Exercise Induced Tachycardia after Cessation of Practolol Therapy

Autor: O. Hunt, Penney Cole, J. G. Sloman, Jayne Ramshaw, C. McRae
Rok vydání: 1977
Předmět:
Zdroj: Australian and New Zealand Journal of Medicine. 7:111-113
ISSN: 0004-8291
DOI: 10.1111/j.1445-5994.1977.tb04675.x
Popis: Summary: Two studies were performed to assess the duration of action of practolol following therapeutic dosage and sudden cessation. The first study involved 19 patients who had completed a two-year double-blind study of the possible benefits of practolol following an acute myocardial infarction. Eleven of these patients had received 400 mg of practolol a day and eight had received placebo tablets. Exercise tests on a stationary bicycle were carried out before, and then two-and-a-half, seven and ten days following discontinuation of medication. The patients were exercised up to a work level of 150 watts and the maximum heart rate noted. The resting heart rates were similar in both the practolol and placebo treated patients (P > 005), both while on and after discontinuation of the medication. There was, however, a significant difference in the maximal heart rate achieved on exercise between the practolol and placebo treated patients, while on medication (mean maximal heart rates 106 and 139/min, P 005) after cessation of medication. In the second study, 12 healthy volunteers took practolol (400 mg/day) and placebo, each for a two-week period, in random order. Exercise tests were performed while the volunteers were receiving medication and every 12 hours for 84 hours after cessation of medication. The maximum heart rates again were significantly different to 48 hours (P 005). It is, therefore, concluded that when practolol is given orally for a period of two weeks or more, its duration of action after abrupt cessation is approximately 60 hours, as assessed by the heart rate response to a constant exercise load.
Databáze: OpenAIRE
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