Objective and subjective tremor responses to oral beta 2 agents on first exposure. A comparison of metaproterenol and terbutaline.
Objective and subjective postural tremor responses at 60 and 120 min after drug treatment were studied in 24 veterans with chronic obstructive pulmonary disease who received either 5 mg terbutaline, 20 mg metaproterenol, or a placebo in random order. Subjects were fasting, and had not taken theophylline for 15 to 24 h or any oral sympathomimetics for 2 wk. The mean tremor response to terbutaline and metaproterenol was equal at 60 min, but the 120-min response to metaproterenol was less. When the 60- and 120-min responses were averaged, tremor response to terbutaline was significantly greater than that to metaproterenol in a 5 : 4 ratio. Subjective awareness was also greater. These results are consistent with the difference in bronchodilatory potency of the two preparations. That the drug producing the greater tremor could usually be identified by the patient, even at low tremor intensities, is consistent with the hypothesis that perception of tremor is a function of relative rather than absolute increase over basal tremor unless the tremor becomes physically disabling. In general, the individual tremor response was proportional to the extent by which a patient's basal tremor exceeded the minimal basal tremor for the group as a whole. These results fit a model in which the postural tremor derives from beta-sensitive and beta-insensitive cardioballistic and skeletal muscle forces. Variability in tremor response resides principally at the peripheral skeletal beta 2-receptor and its control system.
D000284:Administration, Oral; D000368:Aged; D002986:Clinical Trials as Topic; D004311:Double-Blind Method; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000188:drug therapy; D008297:Male; D009921:Metaproterenol / Q000008:administration & dosage / Q000009:adverse effects*; D008875:Middle Aged; D013726:Terbutaline / Q000009:adverse effects*; D014202:Tremor / Q000139:chemically induced*
D009921:Metaproterenol; D013726:Terbutaline