Maternal and fetal cardiovascular effects of transdermal glyceryl trinitrate and intravenous ritodrine.
OBJECTIVE
To determine the maternal and fetal cardiovascular effects of transdermal glyceryl trinitrate compared with ritodrine for acute tocolysis.


METHODS
Sixty women in preterm labor were enrolled in this study that was part of a multicenter study of glyceryl trinitrate. Once randomized, the women received transdermal glyceryl trinitrate or intravenous ritodrine for acute tocolysis. Measurements of maternal pulse, blood pressure (BP), and fetal heart rate (FHR) were recorded for up to 24 hours and compared over the treatment course.


RESULTS
Changes from baseline in mean maternal heart rate, FHR, and maternal BP (mean arterial pressure [MAP]) were compared between the glyceryl trinitrate and ritodrine groups over the entire treatment course. The mean change from baseline in maternal heart rate was 21.1 beats per minute less (95% confidence interval [CI] 15.7, 26.5, P < .001), and the mean maternal heart rate was 21.8 beats per minute lower (95% CI 16.9, 26.7, P < .001) in the glyceryl trinitrate group. The mean change in FHR was 9.2 beats per minute less (95% CI 3.8, 14.6, P = .001) and the mean FHR significantly lower (6.9 beats per minute, 95% CI 1.9, 11.9, P = .008) during glyceryl trinitrate treatment. Ritodrine had a significantly hypotensive effect on MAP (95% CI -4.3, 0.0, P = .03). Mean arterial pressure was not significantly different over the treatment course.


CONCLUSIONS
At doses required for acute tocolysis, transdermal glyceryl trinitrate had minimal effects on maternal pulse, BP, and FHR, and significantly fewer adverse cardiovascular effects than intravenous ritodrine. Thus, transdermal glyceryl trinitrate might be a safer treatment for women in preterm labor.
Black
R S
RS
Academic Department of Obstetrics and Gynaecology, St. George's Hospital Medical School, London, United Kingdom. johnjmblack@msn.com
Lees
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C
Thompson
C
C
Pickles
A
A
Campbell
S
S
D000279:Administration, Cutaneous; D000328:Adult; D002319:Cardiovascular System / Q000187:drug effects* / Q000196:embryology*; D005260:Female; D005333:Fetus / Q000187:drug effects*; D006801:Humans; D007275:Injections, Intravenous; D005996:Nitroglycerin / Q000008:administration & dosage*; D011247:Pregnancy; D012312:Ritodrine / Q000008:administration & dosage*; D015149:Tocolytic Agents / Q000008:administration & dosage*; D014665:Vasodilator Agents / Q000008:administration & dosage*
D015149:Tocolytic Agents; D014665:Vasodilator Agents; D005996:Nitroglycerin; D012312:Ritodrine