Can a cyclo-oxygenase type-2 selective tocolytic agent avoid the fetal side effects of indomethacin?

Premature closure of ductus arteriosus after a single dose of diclofenac during pregnancy

A male term neonate was admitted to the neonatal intensive care unit in the first hours of life with central cyanosis. Echocardiogram showed severe biventricular hypertrophy, markedly right-sided, tricuspid regurgitation, a patent foramen ovale and a closed ductus arteriosus (CDA). The mother recalled being treated with a single dose of intravenous diclofenac for low back pain 2 weeks earlier. The newborn was started on propranolol with symptomatic improvement and was discharged on day 10. At 1-month follow-up, he showed complete resolution of ventricular hypertrophy and suspended propranolol. In the literature, of the 22 cases of CDA after intrauterine exposure to diclofenac, 11 resolved in utero, 3 required ventilatory and inotropic support and 1 evolved to persistent pulmonary hypertension. In this case, a thorough anamnesis was key to identify the probable cause of an otherwise unexplained transient ventricular hypertrophy. This case also alerts to the fetal risks of non-steroidal anti-inflammatory drugs during the third trimester, requiring close monitoring.

Using celecoxib for the suppression of preterm labor instead of magnesium sulfate

We aimed to use celecoxib to suppress preterm labor instead magnesium sulfate (MgSO₄) to prevent preterm labor. Methods. It was a randomized clinical trial study, which was done on 600 pregnant women. All subjects were divided into two groups by simple random sampling. One group was given 4 grams of MgSO₄ intravenously and second group was given 100 mg of celecoxib orally every 12 hours for at least 2 days. The data were entered and analyzed using SPSS 11 and performed using t-test and chi-square test. Results. The finding of this study has shown that preterm labor may be prevented in 75.7% of subjects who had received celecoxib and there were no significant difference between two groups in frequency of history of preterm labor (P = 1), frequencies of nulliparity (P = 0.99), duration of drug use and arrest contraction (P = 0.29), delivery before 48 hours (P = 0.20), and mean gestational age in lack of response to treatment (P = 0.24). Conclusions. Result has shown that celecoxib was similar to MgSO₄ as a medication to prevent preterm labor; it was recommended to be prescribe to prevent preterm labor, because it was cheaper than magnesium sulfate.

Prostaglandin endoperoxide H synthase inhibitors and other tocolytics in preterm labour

Preterm delivery (<37 weeks of gestation) is the major obstetrical complication in developed countries, yet attempts to delay labour and prolong pregnancy have largely been unsuccessful. One of the many reasons it is so difficult to prevent preterm birth is that the nature of preterm labour changes as a function of gestational age, maternal lifestyle factors or infection, to list a few of the reasons. The inhibitors of prostaglandin endoperoxide H synthase (PGHS), known as the Non-steroidal Antiinflammatory Drugs, have been viewed with interest as tocolytics with promising effectiveness under most conditions of preterm labour. Three isoforms of PGHS exist; the first two, PGHS-1 and -2, have been studied for their catalytic activity, X-ray crystallographic structure, and physiological roles in the adult and the foetus. Mixed inhibitors and isoform-specific inhibitors of PGHS have been developed, and their roles in delaying preterm labour are examined and compared to other tocolytics.

Nimesulide, a cyclooxygenase-2 preferential inhibitor, impairs renal function in the newborn rabbit

Tocolysis with nonsteroidal anti-inflammatory drugs (NSAIDs) has been widely accepted for several years. Recently, the use of the cyclooxygenase-2 (COX2) preferential NSAID nimesulide has been proposed. However, data reporting neonatal acute renal failure or irreversible end-stage renal failure after maternal ingestion of nimesulide question the safety of this drug for the fetus and the neonate. Therefore, this study was designed to define the renal effects of nimesulide in newborn rabbits. Experiments were performed in 28 newborn rabbits. Renal function and hemodynamic parameters were measured using inulin and para-aminohippuric acid clearances as markers of GFR and renal blood flow, respectively. After a control period, nimesulide 2, 20, or 200 microg/kg was given as an i.v. bolus, followed by a 0.05, 0.5, or 5 microg.kg(-1).min(-1) infusion. Nimesulide administration induced a significant dose-dependent increase in renal vascular resistance (29, 37, and 92%, respectively), with a concomitant decrease in diuresis (-5, -23, and -44%), GFR (-12, -23, and -47%), and renal blood flow (-23, -23, and -48%). These results are in contrast with recent reports claiming that selective COX2 inhibition could be safer for the kidney than nonselective NSAIDs. These experiments confirm that prostaglandins, by maintaining renal vasodilation, play a key role in the delicate balance regulating neonatal GFR. We conclude that COX2-selective/preferential inhibitors thus should be prescribed with the same caution as nonselective NSAIDs during pregnancy and in the neonatal period.

A prospective randomized safety trial of celecoxib for treatment of preterm labor

OBJECTIVE

We compared the safety of celecoxib, a selective cyclo-oxygenase-2 inhibitor, with the safety of the nonselective cyclo-oxygenase inhibitor indomethacin, when it was administered for treatment of preterm labor.

STUDY DESIGN

In a randomized, double-blind, placebo-controlled trial, 24 pregnant women in preterm labor at 24 to 34 weeks of gestation received either indomethacin or celecoxib for 48 hours. Clinical assessment, fetal sonography, and Doppler blood flow studies of the fetal ductus arteriosus were performed daily.

RESULTS

Mean maximum ductal flow velocity was significantly elevated over baseline (82.9 +/- 4.6 cm/s vs 111.14 +/- 14.3 cm/s; P =.02) after 24 hours of indomethacin, but not celecoxib. Both medications were associated with a transient decrease in amniotic fluid volume, with a greater effect by indomethacin. The medications were equally effective in the maintenance of tocolysis. There were no significant maternal or neonatal adverse events.

CONCLUSION

In this initial evaluation, the safety of short-term celecoxib in women with preterm labor was superior to that of indomethacin.

Adverse and beneficial effects of tocolytic therapy

In addition to questions raised about the efficacy of many tocolytics, appropriate concern has been voiced about the safety of these potent drugs. Although some degree of risk for adverse effects with drugs promising a strong therapeutic effect can be accepted, caution needs to be exercised when benefits are marginal or unproven. Unfortunately, some of the tocolytics, most notably the betamimetics and magnesium sulfate, have been found to have considerable potential for adverse maternal cardiovascular and respiratory effects. Although less clearly established, the use of indomethacin appears to be associated with increased fetal and neonatal risks. Concerning magnesium sulfate, in addition to the well-known maternal effects, the accumulating evidence showing an increased frequency of adverse outcomes in the fetus and neonate has led to the recommendations to abandon its use entirely as a tocolytic. Given the limitations of our current state of knowledge, nifedipine would appear to be among the more efficacious and safer tocolytics available to use when properly indicated.