ARDS associated with the use of sympathomimetics and glucocorticoids for the treatment of premature labor

A 19-yr-old woman developed adult respiratory distress syndrome (ARDS) in the postnatal period after treatment with dexamethasone and ritodrine for premature labor. An assay of complement activation was positive, suggesting a possible mechanism for this patient's ARDS.

Hyperlactacidemia associated with acute ritodrine infusion

The use of beta-mimetic tocolytics has been associated with various metabolic derangements which have been the topic of investigational reports. Lactic acidosis has been reported to follow concomitant steroid administration. The purpose of this investigation was to delineate more clearly hyperlactacidemia in patients receiving various tocolytics with and without concomitant use of steroids in a prospective manner. Twenty patients in premature labor who received ritodrine had markedly increased blood levels of lactate (baseline, 1.0 +/- 0.1 mmol/L [SEM] versus 3.5 +/- 0.3 mmol/L [SEM] after 6 hours' intravenous infusion). In the other treatment groups, ritodrine plus hydrocortisone, hydrocortisone alone, and magnesium sulfate alone, lactate levels failed to change significantly. Clinical relevance and implications for metabolic alterations associated with beta-mimetic tocolysis are discussed.

Pulmonary edema associated with ritodrine and dexamethasone treatment of threatened premature labor. A case report

Pulmonary edema occurred in association with the use of ritodrine and steroids to treat threatened premature labor. Twin gestation, intravenous ritodrine infusion longer than 24 hours and excessive fluid administration appear to be risk factors for the development of pulmonary edema. Careful case selection, scrupulous attention to the principles of fluid and electrolyte management and central venous pressure monitoring may help to diminish the incidence and severity of this complication of pregnancy.

L/S ratio, biochemical and clinical changes after ritodrine intravenous infusion

The effects of ritodrine hydrochloride on the L/S ratio, the clinical and biochemical status of the mother, and the amniotic fluid were studied in a total of 46 women between the 28th and 35th wk of their pregnancy. An increase in the L/S ratio and creatinine levels in the amniotic fluid, significant changes in the maternal serum levels of potassium, sodium, alpha 1-antitrypsin and glucose were found, whereas the urea levels remained unchanged. Maternal hyperglycemia and hypokalemia in both maternal serum and amniotic fluid, were more pronounced when the ritodrine was infused in 5% dextrose. The findings from monitoring the cardiovascular systems of both mother and fetus, agreed with previous reports. It was concluded that ritodrine hydrochloride has a positive effect on the fetal lung maturation, probably by accelerating the release of surfactant. Its administration, however, should be under laboratory control.

Unexpected cardiac pathology in pregnant women treated with beta-adrenergic agents (ritodrine)

Premature uterine contractions were treated by intravenous beta-mimetics in 190 patients during a 2-year period. History and physical examination were directed toward identification of patients with cardiac problems. Unexpected cardiac pathology was discovered in 14 patients, all of whom exhibited severe and continuous nausea, retrosternal pain, or dyspnea during beta-mimetic administration. Treatment was immediately discontinued in the presence of S-T depression, supraventricular tachycardia, nonspecific T wave changes, and sinus tachycardia with right axis deviation. Further investigation revealed obstructive cardiac myopathy in one case and atrial septal defect in another. Such changes might be identified earlier by more extensive screening procedures (such as electrocardiogram) before drug administration. Administration of beta-mimetic agents may uncover previously unexpected cardiac pathology. Continuation of ritodrine in such cases is contraindicated and potentially hazardous.

Pulmonary edema associated with the use of hydrocortisone and a tocolytic agent for the management of premature labor

Three cases of peripartum pulmonary edema associated with steroid administration are reported. Two patients developed antepartum pulmonary edema after receiving hydrocortisone to promote fetal lung maturity. The third patient developed pulmonary edema shortly after delivery and after having received glucocorticoids antepartum.

Retrospective analysis of the effects of ritodrine and terbutaline in the management of preterm labor

The tocolytic effects, adverse reactions, cost, and duration of therapy of terbutaline and ritodrine used for treating preterm labor were compared using retrospective chart review. Of 614 pregnant women admitted to an obstetrics unit between May 1980 and June 1981 who did not deliver a child during that admission, 48 remained on the unit more than 12 hours, received a tocolytic agent, and had a diagnosis of preterm labor. Of these, 22 women received terbutaline or ritodrine. Eight women were excluded, leaving 14 women in the study group. Maternal and fetal characteristics were tabulated, and patients exposed to terbutaline (seven mothers and seven babies) and ritodrine (seven mothers and eight babies) were compared. There were no significant differences between the terbutaline and ritodrine groups for maternal or fetal characteristics, efficacy of treatment, adverse effects, or duration of therapy. The cost of terbutaline is substantially less than that of ritodrine. Terbutaline and ritodrine appear to be comparable tocolytic agents clinically. The use of terbutaline should be investigated further in view of its lower cost and comparable clinical effects.

The influence of long term beta-mimetic drug administration during pregnancy on blood loss postpartum

Early blood loss after-delivery was measured in all prematurely ending singleton pregnancies (amenorrhea 29-38 wk) during which the patients had been treated with beta-mimetics (ritodrine or fenoterol) for the prevention of premature labor, during a 4 yr study period (1975--1978) (n = 129). For comparison, postpartum blood loss was measured in the same way in all other (not treated) patients who delivered with the same gestational ages during the first 2 yr of the investigation (n = 176). Only vaginal deliveries were included and some patient categories were excluded. Placental weight and episiotomy status were found to effect the amount of early postpartum blood loss at a significant level. Blood loss after delivery was found not to be increased by chronic beta-mimetic treatment, even when this treatment ended less than 24 h before delivery. Moreover, when the treatment--delivery interval exceeded 24 h, the average amount of blood loss by treated patients was less than that of the untreated patients in some comparison categories. No difference in the amount of blood loss was found according to the specific drug that had been used.

Hypertensive crisis associated with ritodrine infusion and betamethasone administration in premature labor

A case is reported of hypertensive crisis associated with treatment of premature labor with intravenous ritodrine hydrochloride and betamethasone. Ritodrine has been in clinical use for over 10 yr in Europe, and recently also in the U.S.A. The drug has proved to be efficient and relatively safe. Yet, a few cases of severe side effects, all related to its effect on the cardiovascular system, have already been reported. The pathophysiology of this episode is unclear, but it is most likely related to the treatment, and should be added to the list of reported side effects of treatment with ritodrine and betamethasone.

[The effect of tokolysis by means if beta- mimetics on fetuses and neonates (author's transl)]

The influence of beta mimetic substances, given to stop premature labor, on the metabolism of the fetus and the newborn was investigated in 32 women. There was a definite rise in Insulin and in the amniotic fluid as well in cord blood, with a tendency to hypoglycemia in the newborn (4 out of 18 babies). No influence on acid base level, blood count. Electrolyts, but a marked increase in Bilirubin levels could be observed. Changes in the ECG could be brought in connection with influences of beta mimetic drugs on the myocardium.

Persistent supraventricular tachycardia following infusion with ritodrine hydrochloride

A rare side effect is reported following treatment of preterm labor with ritodrine hydrochloride. The patient developed persistent supraventricular tachycardia, which had to be changed to normal sinus rhythm by cardioconversion.

Pulmonary edema following ritodrine-saline infusion in premature labor

Twenty-three patients with premature uterine contractions occurring between the 27th and 35th weeks of pregnancy were treated in a prospective and randomized study with intravenous ritodrine in a 0.1 wt/vol% solution of isotonic saline (N = 12) or isotonic glucose (N = 11). The aim of the study was to record the effects of these agents on the water-salt metabolism. In both the saline and the glucose groups there was a statistically significant fall in hemoglobin, hematocrit, and serum albumin (P less than .001). This fall correlated significantly with the dose of ritodrine (P less than .001). Serum renin and aldosterone levels revealed a statistically significant increase (P less than .0005). Seven of 12 patients in the saline group, but none in the glucose group, developed pulmonary congestion requiring treatment. The combination of ritodrine and saline should be used very cautiously, and the authors recommend accurate monitoring of the fluid balance during ritodrine treatment.

Verapamil to inhibit the cardiovascular side effects of ritodrine

Side effects of beta-sympathomimetic drugs are of primary interest in the treatment of preterm labor. Incidence of side effects are dose-dependent, as is the efficacy of the beta-agonist in uterine relaxation. the effect of verapamil (Ca2+) inhibitor with antiarrhythmic action) on ritodrine does not modify the value of ritodrine in prolonging pregnancy, but clearly diminishes the incidence of maternal tachycardia and hypotension. The authors suggest that in the treatment of preterm labor with ritodrine infusion above 200 micrograms/min, the addition of verapamil (dosage, 80-120 micrograms/min) is useful because it substantially reduces the cardiovascular side effects associated with ritodrine hydrochloride.

Direct current conversion of maternal supraventricular tachycardia developed during the treatment of a pregnant heroin addict with ritodrine

During ritodrine (UtoparR) treatment for premature labor, a chronic heroin-addicted patient developed supraventricular tachycardia which was treated by direct current (d.c) conversion, d.c. conversion did not affect the fetus, as judged by the cardiotocogram. As heroin addicts run an increased risk or developing cardiac arrhythmia, caution is advised when treating these patients with beta-mimetics.

A case report of maternal death associated with betamimetics and betamethasone administration in premature labor

A fatal case of pulmonary edema is reported after prolonged treatment with beta-mimetics during pregnancy for threatened premature labor. The mother had received betamethasone in order to enhance fetal lung maturity. Myocardial failure occurred 5 days after discontinuation of betamimetics. The potential toxic effects of beta-adrenergic agents and their association with corticosteroids are discussed. Caution is recommended when high doses of betamimetics are to be delivered to prevent premature labor. No patient should be treated unless her cardiac condition is normal. Cardiovascular evaluation should be regularly performed during the course of treatment. No patient should be discharged after treatment without a normal cardiovascular check-up.

Ritodrine hydrochloride: a betamimetic agent for use in preterm labor. I. pharmacology, clinical history, administration, side effects, and safety

Ritodrine hydrochloride has become the first drug approved in the United States specifically for use in preterm labor. The drug is a beta-sympathomimetic agent with predominant effects upon beta 2 receptors of the uterus. In this report, the pharmacology, distribution, disposition, and excretion are briefly reviewed. Recommendations for selecting patients most likely to benefit from ritodrine are given, together with the dosage and administration schedules that have been found most effective. Although this drug is not without side effects, it has been more thoroughly evaluated in prospective double-blind controlled trials than any of the other agents commonly used in preterm labor. In comparison with these agents, it seems relatively safe and the side effects are usually well tolerated. Part 2 of the paper discusses the evidence for efficacy.

Oral ritodrine maintenance in the treatment of preterm labor

Seventy patients with preterm labor and intact membranes were initially treated with ritodrine hydrochloride to delay preterm delivery. Tocolysis beyond 24 hours was achieved in 59 patients. Fifty-five of the 59 patients were then placed on either oral ritodrine or placebo as maintenance therapy in a randomized double-blind manner. If preterm labor recurred, the sequence of intramuscular and then oral treatment was repeated. The number of days gained after initiation of intramuscular treatment was similar in both groups (oral ritodrine = 34 days, oral placebo = 36 days). In those 55 patients receiving oral treatment, there was a smaller number of relapses requiring repeat intramuscular treatment in the oral ritodrine group (1.11 in the ritodrine patient vs. 2.71 in the placebo patient, p less than 0.05), and the mean interval between beginning oral treatment and the first relapse/delivery was 5.8 days in the oral placebo group and 25.9 in those receiving oral ritodrine (p less than 0.05). Cardiovascular side effects, notably maternal tachycardia and palpitations were frequent but well tolerated. The results suggest that oral ritodrine maintenance will decrease the incidence of recurrent preterm labor in patients who have had initial successful tocolysis.

Metabolic effects of intravenous ritodrine infusion in pregnancy

The effects of intravenous administration of Ritodrine on blood glucose, insulin, electrolytes, plasma and red cell potassium and venous pH were investigated. A highly significant increase in blood glucose and insulin occured. A highly significant negative correlation between serum and red cell potassium concentration was registered (r = -0.96268). No signficant changes during Ritodrine infusion were recorded in serum levels of sodium, chloride, calcium, phosphorus and magnesium. The pH did not seem to be influenced by intravenous Ritodrine administration. No cardiac arrhythmias or electrocardiographic deteriorations occurred. While intravenous Ritodrine administration seems to be safe in normal pregnancies, a risk may be present in diabetic and digitalized patients, and pregnant women being treated by diuretics.

Maternal pulmonary edema occurring after therapy with ritodrine for premature uterine contractions

Intravenous administration of beta-sympathomimetic drugs in combination with betamethasone or dexamethasone is a treatment often used for the suppression of premature uterine contractions and for the stimulations of fetal lung maturity. It has been suggested that the combination of these drugs may be responsible for maternal pulmonary edema and five such cases have been reported in the literature (1,2). We report a patient who developed pulmonary edema during ritodrine therapy. Corticosteroids were not given in this case.

[Does myocardial damage arise as a result of administration of tocolytic drugs? (author's transl)]

Fifty pregnant women admitted consecutively on account of threatened abortion or premature labour and treated with Ritodrine and Verapamil intravenously in the usual dosage were investigated with respect to creatine kinase activity and, in the event of a raised level, its isoenzyme creatine kinase--MB. Determinations were carried out before treatment and, in accordance with expected peak values in case of myocardial necrosis, after 6 and 12 hours. Three pathological values were recorded and these are discussed individually. Furthermore, statistical evaluation of the recorded values showed no significant differences.

[Does myocardial damage arise as a result of administration of tocolytic drugs? (author's transl)]

Fifty pregnant women admitted consecutively on account of threatened abortion or premature labour and treated with Ritodrine and Verapamil intravenously in the usual dosage were investigated with respect to creatine kinase activity and, in the event of a raised level, its isoenzyme creatine kinase--MB. Determinations were carried out before treatment and, in accordance with expected peak values in case of myocardial necrosis, after 6 and 12 hours. Three pathological values were recorded and these are discussed individually. Furthermore, statistical evaluation of the recorded values showed no significant differences.

Double blind trial of ritodrine and placebo in twin pregnancy

In a double blind trial, 25 patients with twin pregnancy were given 40 mg of ritodrine hydrochloride by mouth daily and 24 similar patients received a placebo. The ritodrine group had no significant prolongation of pregnancy nor increase in birth weight, and a high incidence of side effects occurred.

[Congenital atrial flutter with hydrops fetalis caused by tocolytic therapy (author's transl)]

A 31-year-old healthy woman received Ritodrine (Pre-Par) from the 26th week of gestation because of twin pregnancy. Three weeks before birth continous intravenous medication with the same drug was commenced because of premature uterine contractions. Five days later a heart rate of over 200/minute was noted in one of the twins. This tachycardia persisted until birth while the heart rate of the other twin remained normal. At 33 weeks monozygotic female twins were delivered after artifical rupture of membranes. One twin was normal, birth weight 1.6 kg. The other baby showed persistent atrial flutter, was hydropic (weight 2.75 kg) and suffered from gross cardiac failure. Atrial flutter was converted to sinus rhythm one hour after birth by DC-countershock. Digoxin was commenced, the child rapidly improved and now still remains in sinus rhythm six month later.