24-Hour Ambulatory Blood Pressure Monitoring: A Comparison Between Transdermal Glyceryl-Trinitrate and Oral Nifedipine

The objective of the present study is to compare the effectiveness of transdermal glyceryl-trinitrate versus oral nifedipine in lowering blood pressure in patients affected by pregnancy-induced hypertension (PIH). Thirty-six consecutive pregnant women have been evaluated at different gestational ages after the diagnosis of PIH or preeclampsia (PE). After a 24-h ambulatory blood pressure monitoring, patients were allocated to three groups: those receiving oral nifedipine and those receiving transdermal glyceryl-trinitrate in a continuous (24 h/day) or intermittent (16 h/day) administration. A second blood pressure monitoring was performed after 2 weeks of treatment. Systolic and diastolic blood pressure were compared by using the Cosinor method looking at mesor, amplitude, and acrophase. Baseline systolic and diastolic blood pressure was similar among the three groups. Neither the transdermal glyceryl-trinitrate administered for 24 or 16 h nor oral nifedipine affected systolic and diastolic blood pressure. Analysis of variance showed that the posttreatment values were similar among the groups. Further studies are needed to verify the possible use of transdermal glyceryl-trinitrate as an antihypertensive drug during pregnancy.