Discussion
vomit, nausea, chest pain, palpitation, hypertensive, headache, reduction of blood pressure
ADVERSE EFFECTS, HYPERTENSION IN PREGNANCY
To date, ACOG has recommended three types of first-line drugs that can be used as emergency management of hypertension in pregnancy: oral nifedipine, intravenous labetalol, and intravenous hydralazine. The blood pressure targets to be achieved in patients with hypertensive emergencies in pregnancy differ from one guideline to another.
Our data suggested that oral nifedipine and intravenous labetalol and hydralazine regimens can be used to treat hypertensive emergencies in pregnancy. If 20-25% reduction of MAP is used as the target, where three doses was set as the maximum, the intravenous hydralazine monotherapy had the lowest failure rate (1 patient). In contrast, intravenous labetalol monotherapy had a failure rate 7 patients (35%, 7/20 patients). As reported previously, labetalol group had relatively low efficacy and required cross-treatment or alternative treatment.
Based on the data of systolic pressure following post-administration time, nifedipine had maximum effectiveness by one dose of administration, but experienced a rebound after 4 hours. As in the labetalol group, the blood pressure reduction peaked twice; at post-20 and -60 minutes administration. Patients in hydralazine group had the lowest blood pressures at three points of measurement: at post-20, -40, and -60 minutes administration. These findings suggest that titration dose is required. Comparative analysis among the three drugs using a single dose yielded a statistical significance of p=0.037. When administered with a single dose, nifedipine performed the best, followed by labetalol and hydralazine and no significant difference of efficacy between labetalol and nifedipine. The result is similar to the finding from a previous study
According to the ACOG guidelines, the maximum dose of emergency antihypertension is 3 times administration within 60 minutes. The comparative analysis revealed that hydralazine yielded the most optimum reduction of blood pressure, followed by nifedipine and labetalol, respectively. This could be observed through the significant reduction of blood pressure on the first until the fourth measurements.We did not witness any adverse effects experienced by the mothers or infants following the drug administration, in which our data are similar to that of reported.
The strengths of this study include the multicentred randomized controlled study design, intensive monitoring, and repeated measurements up to seven times. However, this study is limited by the fact that some of the hospitals only used single blinding because labetalol and hydralazine are new to some doctors. We also did not consider the circadian rhythms in our study and this might affect the blood pressure. Some of the side effects were measured subjectively such as nausea, vomit, dizzy, palpitation, headache and chest pain. However, the methods were exactly the same in all groups.