Theeffect ofnifedipine onthedisposition ofstrontium gluconate used asakinetic marker forcalcium inhealthy volunteers

1 We havestudied thedisposition ofstable strontium after theintravenous administration ofstrontium gluconate toeight healthy malevolunteers bothincontrol conditions andwhile they were taking thecalcium antagonist nifedipine 10mg three times daily. 2 Nifedipine, presumably byitsaction inblocking voltage-operated calcium channels, altered theinvivodisposition ofstrontium, causing large reductions inthehalf-life and theapparent volumeofdistribution ofstrontium. Totalandrenalclearances of strontium were unaltered bynifedipine. 3 Theseresults support our previous suggestion thatthedelineation ofstrontium disposition canbeused asameans ofstudying calcium disposition invivoinman,and ofstudying theeffects ofdrugs anddiseases on thatdisposition.