Dose tolerance and pharmacokinetic studies of L (+) pseudoephedrine capsules in man.
Dose tolerance and pharmacokinetic studies of pseudoephedrine sustained action capsules were performed in thirty-three adult male subjects who received either 120 mg or 150 mg capsules every twelve hours for seven consecutive days in a double-blind parallel design study. Although only one subject in the 150 mg group was discontinued prematurely from this study, a large number of side effects typical of CNS stimulation were seen. A placebo effect might account for a portion of these complaints, however symptoms evaluated as being due to drug were significantly more severe and persistent in the 150 mg group. Pulse rates showed a persistent and significant increase while systolic and diastolic blood pressure fell from the baseline values in both groups. A pharmacokinetic analysis of the pseudoephedrine plasma concentration-time data provided estimates of half-life and the volume of distribution/availability ratio. The values obtained were in good agreement with values reported by others. Half-life was not influenced by urine pH probably as a result of the narrow range of urine pHs observed in the subjects. Calculations of relative bioavailability suggest that the 120 mg capsule formulation has a 30% greater bioavailability compared to the 150 mg capsule.
D000328:Adult; D001682:Biological Availability; D001794:Blood Pressure / Q000187:drug effects; D002214:Capsules; D003692:Delayed-Action Preparations; D004311:Double-Blind Method; D004809:Ephedrine / Q000008:administration & dosage / Q000009:adverse effects* / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008297:Male; D011674:Pulse / Q000187:drug effects; D013997:Time Factors
D002214:Capsules; D003692:Delayed-Action Preparations; D004809:Ephedrine