title: Hemodynamic effects of nifedipine tocolysis.
abstract: OBJECTIVE
  To describe the effects of nifedipine tocolysis on blood pressure and heart rate in non-hypertensive women.
  
  
  METHODS
  This was a retrospective study from 2001 to 2011 to compare blood pressures and heart rates among non-hypertensive women on nifedipine tocolysis up to 8 h after nifedipine initiation. Measurements at 20-60 and 61-120 min were compared to assess the differential effects of dosing on hemodynamics and reflected the effects of the initial and complete loading doses, respectively. Charts were reviewed for hypotension-related emergent delivery.
  
  
  RESULTS
  One hundred and thirty-eight patients were included. Over the 8-h study interval, mean systolic blood pressure (P < 0.001) and mean diastolic blood pressure (P < 0.001) decreased by 5 mmHg and heart rate increased by 4 b.p.m. (P < 0.001). Systolic and diastolic blood pressures were unchanged from baseline up to 120 min at all doses. Heart rate increased at both 20-60 and 61-120 min when all doses were considered (P < 0.001), but differential dosing effects were not observed. Rates of tachycardia increased (P < 0.001), but rates of hypotension were unchanged. No hypotension-related emergent deliveries occurred.
  
  
  CONCLUSIONS
  Nifedipine tocolysis was associated with hemodynamic changes in non-hypertensive women. Tachycardia was increased but hypotension was unaffected, supporting the general safety of nifedipine in this setting.
authors.affiliation: Department of Obstetrics, Gynecology and Women's Health, John A Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, USA.
authors.forename: Kelly
authors.initials: K
authors.lastname: Yamasato
authors.forename: Janet
authors.initials: J
authors.lastname: Burlingame
authors.forename: Bliss
authors.initials: B
authors.lastname: Kaneshiro
mesh_terms: D000293:Adolescent; D000328:Adult; D001794:Blood Pressure / Q000187:drug effects; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007022:Hypotension / Q000139:chemically induced*; D009543:Nifedipine / Q000009:adverse effects*; D011247:Pregnancy; D012189:Retrospective Studies; D013610:Tachycardia / Q000139:chemically induced*; D015145:Tocolysis; D015149:Tocolytic Agents / Q000009:adverse effects*; D055815:Young Adult
chemical_list: D015149:Tocolytic Agents; D009543:Nifedipine
keywords: blood pressure; heart rate; hypotension; nifedipine; preterm labor; tocolysis