Nimesulide and neonatal renal failure

Cyclooxygenase inhibitors for treating preterm labour: What is the molecular evidence? 1

Preterm birth (<37 weeks of gestation) significantly increases the risk of neonatal mortality and morbidity. As many as half of all preterm births occur following spontaneous preterm labour. Since in such cases there are no known reasons for the initiation of labour, treatment of preterm labour (tocolysis) has sought to stop labour contractions and delay delivery. Despite some success, the use of cyclooxygenase (COX) inhibitors is associated with maternal/fetal side effects, and possibly increased risk of preterm birth. Clinical use of these drugs predates the collection of molecular and biochemical evidence in vitro, examining the expression and activity of COX enzymes in pregnant uterine tissues with and without labour. Such evidence is important to the rationale that COX enzymes are, or are not, appropriate targets for the tocolysis. The current study systematically searched existing scientific evidence to address the hypothesis that COX expression/activity is increased with the onset of human labour, in an effort to determine whether there is a rationale for the use of COX inhibitors as tocolytics. Our review identified 44 studies, but determined that there is insufficient evidence to support or refute a role of COX-1/-2 in the onset of preterm labour that supports COX-targeted tocolysis.

Genotoxicity of nimesulide in Wistar rats

It is mandatory for all new drugs to be tested for their potential genotoxicity in addition to general toxicity testing. Some old drugs have not been tested adequately for their genotoxic effects because these were in use before the local regulations were enforced. According to the material safety database, the toxicological effect of nimesulide is not yet fully understood. The present study therefore aimed to explore the genotoxic potential of nimesulide in Wistar albino rats. Nimesulide at the dose level of 50 (Gr-50), 100 (Gr-100) and 200 (Gr-200) mg/kg body weight (b.w.) was given orally. Each rat in treated groups (Gr-50 to Gr-200; n = 10) and negative control group (Gr-NC; n = 10) were administered orally (p.o.) with nimesulide and normal saline, respectively, for 14 days. Similarly, rats of positive control (Gr-PC; n = 10) were administered with cyclophosphamide (CPA; 20 mg/kg b.w.) intraperitoneally. CPA served as positive control, whereas normal saline served as as negative control. Approximately 1-2 mL of blood was collected from retro-orbital sinus for comet assay and subsequently rats were sacrificed to aspirate the femoral bone marrow for the micronucleus test. Structural chromosomal aberration, micronucleated polychromatic erythrocytes (MnPCEs), polychromatic erythrocytes (PCEs) and comet tail length were calculated using micronucleus assay and comet assay, respectively, which served as markers of genotoxicity. In the present study, it was observed that a significant increase in (1) different classified structural chromosomal aberrations with increase in nimesulide dose, such as gaps (50 mg/kg), gaps, breaks and pulverizations (100 mg/kg) and gaps, breaks, fragments, rings and pulverizations (200 mg/kg) and (2) % MnPCE and comet tail length was observed in animals treated with CPA (p < 0.001) or 200 mg of nimesulide (p < 0.05), as compared to negative control. In conclusion, nimesulide (200 mg/kg b.w.) produced a potential genotoxicity in rats.

Quantum dots (QDs) based fluorescent sensor for the selective determination of nimesulide

Fluorescent PET (Photoinduced Electron Transfer) has been of particular growth in recent times. A novel PET based fluorescent sensor using unmodified CdSe quantum dots (QDs) has been developed for the trace determination of Nimesulide (NIM). The sensor is based on the selective fluorescence quenching of quantum dots by NIM in presence of other NSAIDs and is found that intensity of quenching is linearly related to NIM concentration in the range 8.2 × 10(-7) - 4.01 × 10(-5) M. The mechanism of interaction is discussed. Finally, the potential application of the proposed method for the trace determination of NIM in pharmaceutical formulation is demonstrated.

Experience of the use of nimesulide, a cyclo-oxygenase-2 selective prostaglandin synthesis inhibitor, in the prevention of preterm labour in 44 high-risk cases

We report pregnancy outcome and fetal side effects in women at high risk of second trimester loss and early preterm delivery treated with nimesulide. This was a prospective observational study of 44 women treated with nimesulide from 17 to 32 weeks. All women underwent weekly ultrasound scans for AFI, Doppler studies of the ductus arteriosus and transvaginal assessment of cervical length. Outcome data were collected. Oligohydramnios occurred in 54% of cases; this returned to normal in all cases on discontinuation of treatment. There were no cases of constriction of the ductus arteriosus. Thirty-nine women took home a live baby. The mean gestation at delivery was 33 weeks and 1 day and the mean birth weight was 2105 g. Nimesulide appeared to have a significant benefit in women at high risk of preterm delivery with no long-term harmful effects on the fetus if monitored closely with an intensive ultrasound scanning regimen. Randomised placebo controlled trials are required to assess fully the benefit of COX-2 selective and specific prostaglandin synthesis inhibitors.

Pharmacological prevention of prematurity

The acute treatment of premature labour is successful for delaying delivery for short periods of time. Acute tocolysis does not have a significant impact on perinatal outcome. This is likely to be because the process leading to labour occurs over a longer timeframe and therefore therapies instigated as preventative measures are more likely to be successful in delaying delivery. Identification of women at risk of preterm birth is essential to ensure therapies are targeted appropriately. Risk assessments for prediction include previous obstetric history, previous episode of threatened preterm labour, fetal fibronectin status and cervical length. Several groups of pharmacological agents have been studied for the prophylactic treatment of preterm labour. There is no evidence to support the use of tocolytics such as beta-mimetics and oxytocin receptor antagonists. Current studies of calcium channel blockers are too small to draw final conclusions. Non-steroidal anti-inflammatory drugs are associated with side effects on the fetal renal system and ductus arteriosus, making them suitable only for long term use in pregnancy with close ultrasound surveillance. Antibiotics used early in pregnancy in women with abnormal vaginal flora may reduce the risk of preterm birth; however, in women with other risk factors for preterm birth, metronidazole may be associated with an increased risk. The use of progesterone in women with a history of very early preterm labour is likely to be beneficial for preventing preterm labour.

Effects of maternally administered drugs on the fetal and neonatal kidney

The number of pregnant women and women of childbearing age who are receiving drugs is increasing. A variety of drugs are prescribed for either complications of pregnancy or maternal diseases that existed prior to the pregnancy. Such drugs cross the placental barrier, enter the fetal circulation and potentially alter fetal development, particularly the development of the kidneys. Increased incidences of intrauterine growth retardation and adverse renal effects have been reported. The fetus and the newborn infant may thus experience renal failure, varying from transient oligohydramnios to severe neonatal renal insufficiency leading to death. Such adverse effects may particularly occur when fetuses are exposed to NSAIDs, ACE inhibitors and specific angiotensin II receptor type 1 antagonists. In addition to functional adverse effects, in utero exposure to drugs may affect renal structure itself and produce renal congenital abnormalities, including cystic dysplasia, tubular dysgenesis, ischaemic damage and a reduced nephron number. Experimental studies raise the question of potential long-term adverse effects, including renal dysfunction and arterial hypertension in adulthood. Although neonatal data for many drugs are reassuring, such findings stress the importance of long-term follow-up of infants exposed in utero to certain drugs that have been administered to the mother.

Postnatal renal function in preterm newborns: a role of diseases, drugs and therapeutic interventions

Since few data are available about factors affecting renal maturation especially in the lower gestational ages (G.A.), the aim of this work was to study postnatal renal function in a representative population sample of preterm newborns (G.A. <or=36 weeks), admitted to the neonatal intensive care units of seven Italian hospitals, in order to investigate a possible role of drugs, therapeutic interventions and diseases. Data were collected through detailed questionnaires including maternal and neonatal information. To test renal function, serum creatinine and urine output were regularly recorded every 3 days throughout the 1st month of life. A total of 246 subjects were enrolled in the study and divided into four groups according to G.A.: group A, 22-25 weeks; group B, 26-28 weeks; group C, 29-32 weeks; group D, 33-36 weeks. Serum creatinine concentrations at birth were similar in all four groups, while significant differences were evident from the 3rd to the 21st day of life. Within each group, two subpopulations were identified taking into account creatinine values. In subjects with serum creatinine concentrations within the normal range, a physiological decline in creatinine values was observed with increasing postnatal age, and an inverse correlation between creatinine and G.A. was evident from the 3rd day of life to the end of the study period. In neonates with impaired renal function, a marked increase in creatinine values was observed in all neonates from the 3rd day of life, with significant differences among groups on days 7 and 10. Whereas many risk factors were correlated (univariate analysis) with impaired renal function, the multivariate analysis identified only five factors as independent: maternal consumption of nonsteroidal anti-inflammatory drugs (NSAIDs) during pregnancy [odds ratio (OR): 7.38, 95% confidence interval (CI) 3.26-16.7] and intubation at birth (OR: 4.39, 95% CI: 1.2-16.3) were the main risk factors. Respiratory distress syndrome, a low Apgar score and ibuprofen treatment of the neonate were identified as additional risk factors. Our data confirm a multifactorial origin of acute renal impairment in newborns. It is of note that pharmacological treatment with NSAIDs during pregnancy may negatively influence neonatal renal function.

Renal tubular dysgenesis associated with in utero exposure to Nimuselide

Maternal ingestion of the selective cyclo-oxygenase-2 (COX-2) inhibitor Nimuselide has been reported to be associated with the development of oligohydramnios and neonatal renal failure in some cases. We report a case of neonatal renal failure associated with maternal ingestion of Nimuselide in the third trimester of pregnancy. The neonate presented with metabolic acidosis and non-oliguric renal failure on the second day of life. The renal histopathology showed evidence of renal tubular dysgenesis. The child continues to have elevated serum creatinine and hypertension at 10 months of age.

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.

Prescription of Hazardous Drugs During Pregnancy

BACKGROUND

Prescribing drugs to pregnant women requires the balancing of benefits and risks. Only a small proportion of drugs are known to be harmful to the fetus, but for the vast majority of drugs little evidence of fetal safety exists.

AIM

To determine the prescription pattern of potentially and clearly harmful prescription drugs during pregnancy with reference to drug safety categorisation, and to define the drug groups primarily responsible for multiple drug use during pregnancy.

STUDY DESIGN

A retrospective, register-based cohort study.

METHODS

Linkage of three nationwide registers in Finland. Data collection included prescription drugs purchased during the preconception period and each trimester in the pregnant cohort, and the corresponding time periods in the non-pregnant controls. The pregnancy safety categorisation was determined for each drug (Anatomic Therapeutic Chemical [ATC] code) by using the Swedish classification of approved medicinal products (Farmaceutiska Specialiteter i Sverige [FASS]) and if not available, the corresponding Australian (Australian Drug Evaluation Committee [ADEC]) or US categorisation (FDA). GROUPS STUDIED: Women applying for maternity support (maternal grants) during the year 1999 (n = 43 470) plus non-pregnant control women matched by age and hospital district (n = 43 470).

RESULTS

In the pregnant cohort, 20.4% of women purchased at least one drug classified as potentially harmful during pregnancy, and 3.4% purchased at least one drug classified as clearly harmful. A significant decline occurred in the number of pregnant women purchasing potentially and clearly harmful drugs during the first trimester when compared with the preconception period, and the decline continued from the first to the second trimester. In the pregnant cohort, 107 (0.2%) women purchased at least ten different drugs during pregnancy. The drugs most commonly purchased in this group were topical corticosteroids and nasal preparations.

CONCLUSION

The use of hazardous prescription drugs declines during pregnancy but prescriptions of known teratogens and the relatively frequent practice of polypharmacy in epilepsy place emphasis on the need for careful pre-pregnancy counselling. However, drug safety classifications give a very crude estimation of risk and should only be used as general guidelines when planning treatment. Risk assessment must always be made on an individual basis, and pregnant women with illnesses requiring treatment must be treated adequately.

Prescription drugs during pregnancy and lactation--a Finnish register-based study

OBJECTIVE

To examine the use of prescription drugs in Finnish women before and during pregnancy and lactation.

METHODS

A register-based study linking four nation-wide registers in Finland: the Maternal Grants Register, the Drug Prescription Register, and the Special Refund Register (all maintained by the Social Insurance Institution in Finland; KELA), and the Finnish Population Register. The study included all women applying for maternity support (maternal grants) during the year 1999, and non-pregnant control women matched by age and hospital district. Data collection included the number and type of prescription drugs purchased by the two cohorts during preconception (3 months before pregnancy), each trimester, and lactation.

RESULTS

Of the 43,470 pregnant women, 46.2% purchased at least one drug and 12.7% three or more different drugs during pregnancy. Corresponding proportions for the control cohort were 55.2% (OR 0.7, 95% CI 0.6-0.7) and 23.0% (OR 0.5, 95% CI 0.5-0.5). The drugs most frequently purchased during pregnancy were systemic antibiotics (24.1% of pregnant women vs 27.3% controls; OR 0.8, 95% CI 0.8-0.9) and gynaecological anti-infective agents (8.3% vs 1.5%; OR 5.5, 95% CI 5.5-6.5). For pregnant women, purchases of most drug groups had already declined during the first trimester, but no reduction was apparent in drugs for chronic illnesses (epilepsy, asthma, diabetes).

CONCLUSIONS

Although drugs were purchased abundantly during pregnancy, a significant decline occurred for most drug groups. The medication pattern for chronic illnesses remained unchanged. The purchase of several different drugs was relatively common and raises concerns.

The adverse renal effects of prostaglandin-synthesis inhibitors in the newborn rabbit

Nonsteroidal anti-inflammatory drugs are frequently used during pregnancy (premature labor, polyhydramnios) and the immediate postnatal period (closure of patent ductus arteriosus). This article evaluates the renal effect of 3 nonspecific COX inhibitors (aspirin, indomethacin, and ibuprofen) in newborn rabbits. Five groups of anesthetized, ventilated, normoxemic 6-day-old rabbits (n = 52) were administered intravenous aspirin (40 mg/kg), indomethacin (2 mg/kg), and ibuprofen (0.02, 0.2, 2.0 mg/kg, respectively). Renal function and hemodynamics as assessed by inulin and para-aminohippuric acid clearances were measured before and in the hour after drug administration. In all groups of animals, the nonselective COX inhibitors induced an increase in renal vascular resistance and a consequent decrease in glomerular filtration rate and renal blood flow. Urine flow rate decreased significantly in all groups, except in the group receiving the lowest dose of ibuprofen. In newborn rabbits, aspirin, indomethacin, and ibuprofen induced intense renal vasoconstriction, which resulted in impaired renal function. This observation illustrates the major renal protective role played by the vasodilatory prostaglandins during the neonatal period, when the kidney is perfused at very low perfusion pressure. We conclude that all COX inhibitors should be administered with the same caution to the preterm neonate.

Structure toxicity relationships--how useful are they in predicting toxicities of new drugs?

This chapter provides just a few newer examples of structural moieties found in drugs that have been associated with reactive metabolite formation and toxicities. For a discussion of several other structures in drugs that undergo metabolic activation to reactive intermediates, the reader is directed to previous volumes in this series and other chapters in this book, as well as a previous condensed review (Nelson, 1982). Since that review, some new knowledge allows us to better predict that some structural moieties are more likely than others to form drug reactive metabolites that may be involved in causing toxic effects in humans. For example, most aniline-, thiophene-, and nitroaromatic-containing drugs have had a relatively high incidence of adverse effects, and it would be prudent in the drug discovery process to avoid these substructures if possible. However, as illustrated by the case of olanzapine, these structures may be important for potent activity, and could therefore be beneficial in some cases. The glitazones represent a new class of drugs with a unique thiazolidinedione structure. This raises two important points. First, it demonstrates how limited our knowledge base is in regard to structure toxicity relationships when new structures are introduced. Our approaches must be very empirical and are far from quantitative for the reasons outlined in the introduction. Secondly, the glitazones point out the importance of benefit/risk considerations. This was a new structural class of drugs with a unique spectrum of action that is very beneficial in the treatment of a major disease. Despite some suspected risk of toxicity, based on early trials, troglitazone was approved for use with careful monitoring. This author believes that was the right decision, as was the decision to withdraw the drug when the risk became unacceptable, especially with the introduction of safer alternatives. If this were just another NSAID (e.g., bromfenac), there would be little reason for approval. In summary, as I pointed out previously (Nelson, 1982), with our limited knowledge of structure toxicity relationships, we can only make reasonable judgments as to risk assessment of a new drug in humans, and hope that we neither release a dangerous chemical entity nor, as importantly, abort an effective one.

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

We evaluated the efficacy and safety of nimesulide (100 mg orally twice daily for > 48 hours) in a pilot series of five women (two with twin pregnancies) at 24(+6) weeks (range 21(+3) - 27(+2)) in preterm labour which was unresponsive to intravenous ritodrine. Nimesulide therapy was continued for eight days (5-16) and was associated with a prolongation of pregnancy of 27 days (6-69). Oligohydramnios occurred in all seven fetuses after three to nine days of therapy, and in the five pregnancies that continued after discontinuation of nimesulide, it resolved within four days (2-7). None of the babies manifested permanent renal damage.