Voriconazole-induced QTc prolongation in a paediatric population

AIM

To evaluate Corrected QT (QTc) interval prolongation (QTcP) in paediatric patients treated with voriconazole (VRC) and identify its associated risk factors in this setting.

METHODS

Clinical, VRC-related and QTc interval data were collected retrospectively from the electronic medical records of VRC-treated paediatric patients attending a large tertiary medical centre in 2011-2016 who underwent electrocardiography before and during therapy. Paired comparison of QTc intervals before and during VRC treatment was performed, adjusted for concurrent medications, electrolyte disturbances and co-morbidities.

RESULTS

Fifty-five patients (mean age 10.1 ± 5.4 years) met the inclusion criteria; 34 had an oncologic or hemato-oncologic diagnosis. Mean QTc interval was 402.8 ± 27.9 msec before VRC treatment and 440.0 ± 45.3 msec on treatment (p < 0.001). During treatment, 38 patients (61.8%) had QTcP ≥30 msec and 17 (30.9%), QTcP ≥60 msec; 10 patients (18.2%) had QTc ≥500 msec of whom one acquired torsades de pointes. On multivariate analysis, older age (p = 0.025), lower potassium level (p = 0.025) and longer baseline QTc (0.032) were associated QTcP ≥60 msec, but not daily or cumulative dose of VRC.

CONCLUSION

This study demonstrated a high rate of clinically significant QTcP in VRC-treated children. Proper QTc monitoring, together with laboratory monitoring and electrolyte imbalance correction, is important to prevent cardiac arrhythmias in this patient population.

Voriconazole-induced QT prolongation among hemato-oncologic patients: clinical characteristics and risk factors

PURPOSE

The purpose of this study is to determine the rate of QTcP and associated risk factors in patients treated with voriconazole.

METHODS

We conducted a retrospective chart review of all patients treated with voriconazole in a large tertiary center between 2009 and 2015, using paired comparison of QTc intervals on and off voriconazole treatment, adjusted for comorbidities, electrolyte abnormalities, and concurrent medications.

RESULTS

Fifty-four patients were included, of whom 53 were diagnosed with oncologic/hemato-oncologic disease. Mean QTc during voriconazole therapy (448.0 ± 52.9 msec) was significantly longer compared to QTc off voriconazole (421.8 ± 42.2 msec; p = 0.002). QTcP ≥30 msec and ≥60 msec was demonstrated in 43% (23 patients) and 28% (15 patients), respectively. Multivariate analysis showed that QTcP was significantly associated with baseline QTc ≥ 450 msec (upper QTc quartile) (p < 0.01) and low serum potassium levels (p < 0.01). Contrarily, no significant association was found between mean voriconazole daily and cumulative dose and QTcP.

CONCLUSION

Our findings indicate that hemato-oncologic patients treated with voriconazole are at increased risk for QTcP, especially in the presence of baseline QTc ≥ 450 msec and low serum potassium levels.

Deferiprone-Induced Agranulocytosis : A Critical Review of Five Rechallenged Cases

The most serious adverse effect of deferiprone, the first orally active iron chelator, is agranulocytosis afflicting an estimated 1.6% of patients. Among the 13 reported patients who had experienced deferiprone-induced agranulocytosis or severe neutropenia, 5 were rechallenged. We studied the onset, clinical and rechallenge course of all 5 patients in an attempt to characterise the mechanisms involved in deferiprone-induced agranulocytosis, to verify whether rechallenge in future patients is ethically justified. Deferiprone-induced agranulocytosis showed no trend of dose dependency: of all patients who had experienced agranulocytosis 23% were treated with 50 mg/kg/day, 46% with 75 to 90 mg/kg/day, and 31 % with > 90 mg/kg/day. Available data including bone marrow aspiration in some patients support the hypothesis that an early myeloid precursor is the target cell affected by deferiprone. All 5 rechallenged patients re-experienced agranulocytosis/neutropenia. The lag period to agranulocytosis/neutropenia following reinduction was significantly shorter (13.2 ± 21.7 weeks compared with 46.4 ± 14.2 weeks in the first episode; p < 0.05). All but one of the rechallenged patients re-experienced agranulocytosis or neutropenia 2 to 4 weeks following re-exposure to deferiprone, suggesting a possible immune mechanism. We found that deferiprone was oxidised in vitro by hypochlorous acid, the major neutrophil oxidant to produce a myelotoxic metabolite. This reactive species demonstrated neutrophil toxicity and a dose-dependent lymphotoxic curve. However, we found no differences in the toxicity of this reactive species to neutrophils from 2 patients with a history of deferiprone-induced agranulocytosis when compared with controls. In combination with the clinical characteristics, these results suggest a reactive metabolite-induced immune-mediated reaction. These 5 rechallenged cases ethically preclude the rechallenge of additional cases.

Induction infliximab levels among patients with acute severe ulcerative colitis compared with patients with moderately severe ulcerative colitis

BACKGROUND

Infliximab is effective as salvage therapy for patients with steroid refractory acute severe ulcerative colitis (UC). Although current data suggest that the pharmacokinetics of infliximab are influenced by inflammatory burden in patients with acute severe UC, data comparing infliximab trough levels in patients with acute severe UC vs. moderately severe UC are scarce.

AIM

To compare infliximab trough and anti-infliximab antibody levels at a standard fixed time-point during induction between patients with acute severe and moderately severe UC.

METHODS

A multi-centre retrospective study comparing infliximab drug and antibody levels 14 days after the first infusion in hospitalised acute severe UC versus out-patients with moderately severe UC was performed.

RESULTS

Sixteen acute severe UC patients, hospitalised between 2010-2015 and refractory to intravenous corticosteroids, were treated with infliximab 5 mg/kg salvage therapy. They were compared to 16 moderately severe UC out-patient controls. Mean infliximab trough levels at day 14 were significantly lower in patients with acute severe UC compared to moderately severe UC (7.15 ± 5.3 vs. 14.4 ± 11.2 μg/mL, P = 0.007). Seven patients (three acute severe and four moderate severe UC) were primary nonresponders to infliximab induction therapy. Infliximab level at day 14 did not differ between responders and nonresponders (9.8 ± 9 vs. 12.1 ± 10.6 μg/mL, respectively, P = N.S.). However, week 2 median antibody-to-infliximab levels were numerically higher among primary nonresponders (3.4 ± 5.7 vs. 1.2 ± 4 μg/mL-eq, respectively, P = 0.06).

CONCLUSIONS

Infliximab trough levels at day 14 were lower in patients with acute severe UC compared to moderately severe UC, possibly due to a higher inflammatory burden and/or increased drug clearance. However, drug levels at day 14 were not lower among nonresponders compared with responders. Controlled trials are warranted to examine whether an a-priori-intensified infliximab induction protocol will lead to an improved outcome in acute severe UC.

Undetectable anti-TNF drug levels in patients with long-term remission predict successful drug withdrawal

BACKGROUND

Low drug levels are associated with emerging loss of response to anti-TNF. However, this may not be the case in patients with long-term remission.

AIM

To investigate the outcome of anti-TNF discontinuation in patients with long-term remission and incidental undetectable drug levels.

METHODS

A retrospective cohort study examining the duration of relapse-free survival in IBD patients in remission who discontinued infliximab or adalimumab having undetectable drug levels.

RESULTS

Forty eight patients who discontinued anti-TNF while in remission and had available drug levels were identified in two centres in France and Israel (infliximab-treated 35, adalimumab-13, Crohn's disease 30, ulcerative colitis 18, mean treatment duration of 22.7 ± 12.4 months). Endoscopy/MRE before stopping showed absence of active inflammation in 40/42 (95%) of evaluated patients, while inflammatory biomarkers (CRP and/or Calprotectin) were completely normal in only 31/48 (65%) of patients. During 12 months median follow-up, relapse occurred in 16/20 (80%) of patients who stopped anti-TNF while having measurable drug levels compared with 9/28 (32%) of patients who had undetectable drug levels (OR: 8.4, 95% CI: 2.2-32, P = 0.002). Relapse-free survival after anti-TNF cessation was significantly longer in patients with absent drug compared to those with detectable drug (P < 0.001, log rank test). On multivariate analysis, a patient's decision to stop therapy was weakly associated and abnormal inflammatory biomarkers and detectable drug levels were both strongly and independently associated with a higher risk of relapse after drug discontinuation.

CONCLUSION

Incidental finding of undetectable anti-TNF drug levels in patients with stable long-term deep remission may identify a subset of patients whose clinical remission is no longer dependent on anti-TNF treatment.

Bioavailability of oral vs. subcutaneous low-dose methotrexate in patients with Crohn's disease

BACKGROUND

Oral methotrexate and folic acid are partly absorbed by a common intestinal transporter.

AIM

: To determine the relative bioavailability of oral low-dose methotrexate administered with and without concomitant folic acid vs. subcutaneous administration in patients with stable Crohn's disease.

METHODS

Ten patients were randomized to receive their regular maintenance dose of methotrexate (15-25 mg) for three consecutive weeks: orally, orally with 5 mg folic acid or subcutaneously. Blood samples were drawn at specified intervals during 24 h, and methotrexate levels were determined by fluorescence immunoassay. Areas under the curve extrapolated to infinity (AUC infinity ) were compared between the three routes.

RESULTS

The geometric mean AUC infinity values (95% confidence intervals) were 360 nmol x h/L (301-430 nmol x h/L), 261 nmol x h/L (214-318 nmol x h/L) and 281 nmol x h/L (209-377 nmol x h/L) per milligram of methotrexate administered for subcutaneous, oral and oral with folic acid administration, respectively (P < 0.05 and P < 0.01 for oral with folic acid and oral vs. subcutaneous administration, respectively). The geometric mean relative bioavailabilities (95% confidence intervals) were 0.73 (0.62-0.86) and 0.77 (0.60-0.99) for oral and oral with folic acid administration, respectively (difference not significant).

CONCLUSIONS

In patients with stable Crohn's disease, the oral bioavailability of methotrexate is highly variable and averages 73% of that of subcutaneous administration. Concomitant folic acid has no significant effect on the bioavailability. Dose adjustments based on individual pharmacokinetic assessment should be considered when switching patients from parenteral to oral therapy.

Effect of a single dose of esmolol on the bispectral index scale (BIS) during propofol/fentanyl anaesthesia

BACKGROUND

Esmolol, a short-acting beta 1-antagonist, can reduce anaesthetic requirements and decrease seizure activity during electroconvulsive therapy even after a single dose of 80 mg. We studied the effect of esmolol on the bispectral index scale (BIS), which is a processed EEG recently introduced to monitor depth of anaesthesia.

METHODS

We gave esmolol 80 mg to 30 healthy male patients after induction of anaesthesia using propofol, with either fentanyl (group 1) or placebo (group 2). Patients were ventilated mechanically through a laryngeal mask airway and anaesthesia was maintained using propofol to keep the BIS value between 55 and 60.

RESULTS

Esmolol did not affect the BIS index value in either group. In group 1, the areas (mean (SD)) under the BIS vs time curve 3 min before and 3 min after esmolol administration were 145 (9) and 146 (8) respectively (P = 0.116). In group 2 values were 147 (8) and 146 (7) respectively (P = 0.344). In contrast, in group 1 the area under the systolic arterial pressure (SAP) curve was 299 (31) before and 270 (29) after esmolol (P < 0.001), and 156 (17) and 141 (17) respectively for heart rate (P < 0.001). In group 2 values were 326 (36) and 302 (41) for SAP (P < 0.001) and 182 (25) and 155 (22) for heart rate (P < 0.001).

CONCLUSIONS

The results suggest that a single dose of esmolol affects the SAP and heart rate but does not affect BIS values.

Interindividual variability in sensitivity to warfarin--Nature or nurture?

BACKGROUND

Interindividual variability in responses to warfarin is attributed to dietary vitamin K, drug interactions, age, or genetic polymorphism in the cytochrome P4502C9 enzyme (CYP2C9) (allelic variants 2C9*2 and 2C9*3 ) linked with impaired metabolism of the potent enantiomere S-warfarin.

PATIENTS AND METHODS

We quantified the relative effects of age and of simultaneously determined CYP2C9 genotype, plasma warfarin and vitamin K concentrations, and concurrent medications on warfarin maintenance doses in 156 patients at optimized stable anticoagulation.

RESULTS

Allele frequencies for CYP2C9*1, CYP2C9*2, and CYP2C9*3 were 0.84, 0.10, and 0.06. Warfarin doses were 6.5 +/- 3.2, 5.2 +/- 2.4, and 3.3 +/- 2.0 mg/d in the 3 genotype groups (P < .0001). Warfarin doses decreased with age as follows: 7.7 +/- 3.7 versus 4.9 +/- 2.9 mg/d at < 50 years and >66 years (P < .001), mainly as a result of decreased plasma warfarin clearance (2.8 +/- 1.4 mL/min versus 1.9 +/- 0.8 mL/min; P < .001). Vitamin K (1.6 +/- 1.1 ng/mL) did not differ among the age or genotype groups. Patients >or=66 years old with the CYP2C9*3 allele required only 2.2 +/- 1.2 mg/d compared with 7.9 +/- 3.7 mg/d in those <or=65 years old bearing the CYP2C9*1 allele (P < .001). On multiple regression, warfarin maintenance doses were independently associated with plasma warfarin (reflecting its metabolic clearance) (r (2) = 0.26), age (possibly reflecting increased intrinsic sensitivity) (r (2) = 0.12), and genotype (reflecting S-warfarin levels) (r (2) = 0.10) but not with plasma vitamin K.

CONCLUSIONS

At optimized steady state, individual sensitivity to warfarin is determined by CYP2C9 genotype and age with no effect of vitamin K. Prospective studies will determine the impact of these findings in clinical practice.

Pregnancy outcome after gestational exposure to terfenadine: A multicenter, prospective controlled study

BACKGROUND

Terfenadine is a selective, nonsedative, H(1)-blocker antihistamine used for a variety of allergic conditions. The widespread popularity of terfenadine and its use by many women in their reproductive age raises concerns regarding its safety during pregnancy. Presently, no prospective controlled study has addressed its safety during gestation.

OBJECTIVE

We sought to determine whether terfenadine use during pregnancy is associated with an increased risk of major malformations, decreased birth weight, perinatal complications, or developmental delays.

METHODS

A multicenter, prospective controlled study was performed. Pregnant women exposed to terfenadine during gestation were matched with control subjects exposed to drugs not known to adversely affect pregnancy outcome. The primary end point was the incidence of major malformations. Secondary outcomes of interest were pregnancy outcome, rates of preterm delivery, birth weight, and developmental milestones.

RESULTS

One hundred eighteen women were exposed to terfenadine during pregnancy. Among those exposed during the first trimester (n = 65), rates of major malformations in the terfenadine group did not differ from rates in their matched control subjects (0% vs 2%; relative risk, 0.57; 95% confidence interval, 0.06-5.39; P =.53). The birth weight in the terfenadine-exposed newborns was significantly lower compared with that in their matched control subjects (3335 +/- 582 vs 3499 +/- 617 g; P =.04). However, the rates of birth weight below 2500 g and birth weight below the 10th percentile for gestational age were not different between the groups. Univariate and multiple regression analysis revealed that none of the terfenadine therapy-related factors (daily dose, duration of therapy, and trimester of exposure) had a significant predictive effect on birth weight. Gestational age at delivery, rates of preterm deliveries, and developmental milestones were comparable between the groups.

CONCLUSIONS

On the basis of the limited sample size of this study, it appears that terfenadine is not associated with a 6-fold or greater increased incidence of major malformations. Terfenadine use during gestation was not associated with increased rates of prematurity or developmental delays. Further studies will be needed to confirm the finding of lower birth weight in newborns exposed to terfenadine.

Risk factors for long-term outcome of ifosfamide-induced nephrotoxicity in children

Ifosfamide is widely used in the treatment of pediatric solid tumors. Its main adverse effects are various forms of renal tubular and glomerular damage. The authors sought to determine factors that predict the risk for the development and severity of ifosfamide-induced nephrotoxicity in children and to examine the long-term outcome of this complication. A total of 174 children who had received ifosfamide for various cancers were studied. Nephrotoxicity was assessed by laboratory markers of glomerular and tubular function and a grading score (none, mild, moderate, severe). Patients were assessed 4 to 12 weeks after each ifosfamide course, 3 months after completion of chemotherapy, and 5 years later. Of 174 children, 72 (41.4%) developed tubular dysfunction, whereas only 11 (6.3%) demonstrated glomerular dysfunction; 40 (23.0%) demonstrated mild toxicity, 16 (9.2%) demonstrated moderate toxicity, and 16 (9.2%) developed severe nephrotoxicity. The four severity subgroups (none, mild, moderate, severe) received comparable doses/m2/cycle of ifosfamide and mesna. Children exhibiting severe toxicity were significantly younger compared to those with moderate, mild, or no nephrotoxicity (median age: 2.2, 7.0, 8.2, and 10.5 years, respectively; p < 0.001) and received significantly higher cumulative doses of ifosfamide (49.6 +/- 12.3, 46.0 +/- 13.1, 36.2 +/- 9.7, and 33.8 +/- 7.6 g/m2, respectively; p < 0.001). Cumulative doses of cisplatin were higher among children with severe nephrotoxicity compared to those with moderate, mild, or no toxicity, although this difference did not reach statistical significance. Of all risk factors analyzed by multiple regression analysis, age was the most significant predictor for the grade of nephrotoxicity (p < 0.001), followed by the cumulative dose of ifosfamide (p = 0.005). Seven out of 16 children (44.0%) with severe nephrotoxicity and 4 out of 16 children (25.0%) with moderate nephrotoxicity demonstrated severe chronic tubular toxicity over a follow-up period of 5 years. Since severe ifosfamide-induced renal toxicity tends to be chronic in a substantial number of treated children, it should be balanced carefully against efficacy. Cumulative ifosfamide doses of 45 g/m2 and above should be carefully considered, especially in children younger than age 3.

Treating allergic rhinitis in pregnancy. Safety considerations

Allergic rhinitis affects approximately one-third of women of childbearing age. As a result, symptoms ranging from sneezing and itching to severe nasal obstruction may require pharmacotherapy. However, product labels state that medications for allergic rhinitis should be avoided during pregnancy due to lack of fetal safety data, even though the majority of the agents have human data which refute these notions. We present a systematic and critical review of the medical literature on the use of pharmacotherapy for the management of allergic rhinitis during pregnancy. Electronic databases and other literature sources were searched to identify observational controlled studies focusing on the rate of fetal malformations in pregnant women exposed to agents used to treat allergic rhinitis and related diseases compared with controls. Immunotherapy and intranasal sodium cromoglycate (cromolyn) and beclo-methasone would be considered as first-line therapy, both because of their lack of association with congenital abnormalities and their superior efficacy to other agents. First-generation (e.g. chlorpheniramine) and second-generation (e.g. cetirizine) antihistamines have not been incriminated as human teratogens. However, first-generation antihistamines are favoured over their second generation counterparts based on their longevity, leading to more conclusive evidence of safety. There are no controlled trials with loratadine and fexofenadine in human pregnancy. Oral, intranasal and ophthalmic decongestants (e.g. pseudoephedrine, phenylephrine and oxymetazoline, respectively) should be considered as second-line therapy, although further studies are needed to clarify their fetal safety. No human reproductive studies have been reported with the ophthalmic antihistamines ketorolac and levocabastine, although preliminary data reported suggest no association between pheniramine and congenital malformations. There are no documented epidemiological studies with intranasal corticosteroids (e.g. budesonide, fluticasone propionate, mometasone) during pregnancy; however, inhaled corticosteroids (e.g. beclomethasone) have not been incriminated as teratogens and are commonly used by pregnant women who have asthma. In summary, women with allergic rhinitis during pregnancy can be treated with a number of pharmacological agents without concern of untoward effects on their unborn child. Although the choice of agents in part should be based on evidence of fetal safety, issue of efficacy needs to be addressed in order to optimally manage this condition.

Meta-analytic review of the clinical effectiveness of oral deferiprone (L1)

OBJECTIVE

To summarize efficacy and effectiveness in iron overloaded patients treated with the orally active iron chelator deferiprone also known as L1 or, using meta-analysis of the literature.

METHODS

We reviewed the literature, searching Medline and Embase databases, as well as reviews and other literature on the topic. Inclusion criteria were: original clinical trials reporting results for serum ferritin concentration (SF), hepatic iron concentration or urinary iron excretion (UIE). Efficacy data had to have been reported after > or =3 months of treatment. Data were combined using a random effects model (Cochrane) modified for use with single groups to produce a point estimate and a 95% confidence interval. To summarize the clinical effectiveness, overall proportion of patients where deferiprone was able to reduce serum ferritin was calculated. We also examined average (mg x l(-1)) serum ferritin levels over the reported time (mean) and absolute decrease from the baseline after therapy. To summarize efficacy, success was defined as the proportion of patients who achieved UIE of 25 mg per day or 0.5 mg x kg(-1) x day(-1), which equals the average amount received from monthly blood transfusions. We also calculated the overall average level (mg per day) of UIE over the reported time of therapy (mean). As part of a sensitivity analysis, data were analyzed for two ranges of deferiprone dosage: < or = 50 mg x kg(-1) x day(-1) and > or =75 mg x kg(-1) x day(-1).

RESULTS

Of 83 identified references, nine clinical trials met our inclusion criteria, providing data for 129 iron overloaded patients. After a mean of 16 months of therapy (range 6.4 36 months) with 66.4 mg x kg(-1) x day(-1) (mean) of deferiprone, 75.5% of highly iron overloaded patients had a decrease in serum ferritin from baseline. The average drop in serum ferritin of 0.8 mg x l(-1) was 23.5% from baseline. The overall average UIE for therapy was 28.8 mg per day in patients receiving > or = 75 mg x kg(-1) x day(-1) over 8.5 months of therapy. At the same dosage, more than half of the patients (51.8%) achieved negative iron balance. When studies with patients receiving lower dosage (< or = 50 mg x k(-1) x day(-1)) were included, the success rate was 45.1%.

CONCLUSION

Overall, deferiprone has clinical efficacy in achieving negative iron balance and reducing body iron burden in highly iron overloaded patients. After an average of 16 months of deferiprone in doses > or = 75 mg x kg(-1) x day(-1), most patients had a decrease in ferritine concentration.

Clinical pharmacology and therapeutic drug monitoring in neonates and children

From a pharmacotherapy perspective, the process of development and growth represents an unstable and dynamic condition. Age-related changes in drug absorption, distribution, and metabolism among neonates, infants, and prepubescent children create a unique situation that may increase drug toxicity of some agents and protect from toxicity of other agents. Understanding the age-related changes in drug disposition that are relevant for therapeutic response and toxicity is essential for optimizing pharmacotherapy at different stages of childhood.

The safety of omeprazole during pregnancy: a multicenter prospective controlled study

OBJECTIVES

Our purpose was to determine whether omeprazole use during pregnancy is associated with an increased risk of malformations, spontaneous abortions, decreased birth weight, or perinatal complications.

STUDY DESIGN

In a multicenter, prospective controlled study, pregnant women exposed to omeprazole during gestation were matched with controls exposed to nonteratogens and with disease-paired controls who used histamine blockers for similar indications. The primary end point was the incidence of major malformations.

RESULTS

One hundred thirteen pregnant women were exposed to omeprazole during pregnancy. Rates of major malformations in the omeprazole group (4%) did not differ from controls exposed to nonteratogens (2%) (P = .68, relative risk = 1.94, 95% confidence interval 0.36 to 10.36) and disease-paired controls (2.8%). Birth weight, gestational age at delivery, preterm deliveries, and neonatal complications were comparable among the three groups.

CONCLUSIONS

No association was found between exposure to omeprazole during the period of organogenesis and increased risk for major malformations. Exposure throughout pregnancy is not associated with increased risk of spontaneous abortions, decreased birth weight, or perinatal complications.

Diabetic nephropathy in hypertransfused patients with beta-thalassemia. The role of oxidative stress

OBJECTIVE

Pathogenesis of diabetes-related microvascular complications involving oxidative damage by free radicals has been demonstrated. Free radical generation has been shown to derive largely from iron. Our objectives, therefore, were to determine if there is an increased incidence and/or an accelerated course of nephropathy in patients with diabetes, secondary to transfusional hemochromatosis, and to examine whether free radical activity contributes to the development of this complication.

RESEARCH DESIGN AND METHODS

We evaluated nine patients with homozygous beta-thalassemia, complicated by clinically overt diabetes, for diabetic nephropathy over a 7-year period. Lipid peroxidation was quantified by measuring the presence of 20 saturated and unsaturated aldehydes, and results were compared with five normotensive type 1 diabetic patients without iron overload.

RESULTS

Nephropathy developed in five of nine patients (55%) after a mean duration of overt diabetes of 3.6 +/- 2.0 years. Three patients showed evidence of progressive microalbuminuria over a 7-year period (24.7-46.2, 52.2-430.1, and 17.7-54.3 micrograms/min, respectively). Two patients with borderline microalbuminuria (19.9 and 14.5 micrograms/min, respectively) demonstrated stable albumin excretion rates over the follow-up period. Total aldehyde concentration was significantly higher in beta-thalassemia diabetic patients, compared with nonthalassemic diabetic control subjects (8,106 +/- 1,280 vs. 4,594 +/- 247 nmol/l; P < 0.0001). The three patients with progressive microalbuminuria demonstrated significantly higher total aldehyde concentration, compared with the other beta-thalassemia diabetic patients with stable albumin excretion (9,428 +/- 337 vs. 7,445 +/- 1,003 nmol/l; P < 0.01). Serum vitamin E concentrations were significantly lower in beta-thalassemia patients with diabetes, compared with diabetic patients without iron overload (12.1 +/- 6.0 vs. 25.9 +/- 11.4 mumol/l; P = 0.02). Serum vitamin C concentrations did not differ between the two groups. Multiple regression analysis demonstrated total aldehyde concentration to be the most significant predictor for the development of microalbuminuria (P = 0.01), followed by the duration of diabetes (P = 0.02) and glycemic control (P = 0.02).

CONCLUSIONS

Early development and an accelerated course of diabetic nephropathy in iron-loaded patients with beta-thalassemia are observed. These findings may be attributed to high oxidative stress in these patients, which is secondary to iron-derived free radicals and to the patients' diminished antioxidant reserves.

Pregnancy outcome following gestational exposure to fluoroquinolones: a multicenter prospective controlled study

Concerns regarding the teratogenicity of fluoroquinolones have resulted in their restricted use during gestation. This is despite an increasing need for their use due to emerging bacterial resistance. The objectives of the present investigation were to evaluate pregnancy and fetal outcomes following maternal exposure to fluoroquinolones and to examine whether in utero exposure to quinolones is associated with clinically significant musculoskeletal dysfunctions. We prospectively enrolled and followed up 200 women exposed to fluoroquinolones (norfloxacin, ciprofloxacin, ofloxacin) during gestation. Pregnancy outcome was compared with that for 200 controls matched for age and for smoking and alcohol consumption habits. Controls were exposed to nonteratogenic, nonembryotoxic antimicrobial agents matched by indication, duration of therapy (+/- 3 days), and trimester of exposure. Rates of major congenital malformations did not differ between the group exposed to quinolones in the first trimester (2.2%) and the control group (2.6%) (relative risk, 0.85; 95% confidence interval, 0.21 to 3.49). Women treated with quinolones had a tendency for an increased rate of therapeutic abortions compared with the rate among women exposed to nonteratogens (relative risk, 4.50; 95% confidence interval, 0.98 to 20.57), resulting in lower live-birth rates (86 versus 94%; P = 0.02). The rates of spontaneous abortions, fetal distress, and prematurity and the birth weight did not differ between the groups. Gross motor developmental milestone achievements did not differ between the children of the mothers in the two groups. We concluded that the use of fluoroquinolones during embryogenesis is not associated with an increased risk of major malformations. There were no clinically significant musculoskeletal dysfunctions in children exposed to fluoroquinolones in utero. The higher rate of therapeutic abortions observed in quinolone-exposed women compared to that for their controls may be secondary to the misperception of a major risk related to quinolone use during pregnancy.

Ifosfamide-induced nephrotoxicity in children: critical review of predictive risk factors

Ifosfamide is widely used in the treatment of pediatric solid tumors. Its main adverse effects are various forms of renal tubular and glomerular damage. Many risk factors have been proposed to play a role in the development and severity of nephrotoxicity in children receiving ifosfamide, among which are 1) patient's age, 2) cumulative ifosfamide dose, 3) concurrent administration of cis or carboplatinum, 4) unilateral nephrectomy, and 5) method of ifosfamide administration. However, presently there is no consensus regarding the weight of each one of them. Therefore, we critically reviewed the major studies that have evaluated the different risk factors in an attempt to determine the relative importance of each. Cumulative ifosfamide doses of >/=60 g/m appears to be the most consistent independent predictor for both the development and the severity of nephrotoxicity, whereas a younger age (<5 years of age) was associated primarily with the more severe and chronic forms of proximal tubulopathy. Comparable incidence and severity forms of proximal tubulopathy among children who had been treated with cis platinum in addition to ifosfamide and those who had not indicate that platinums probably potentiate ifosfamide-induced renal damage rather than act as a major independent risk factor. Finally, although unilateral nephrectomy has been proposed as a significant risk factor in different studies, the relatively small number of nephrectomized children in these cohorts limit the strength of this association. To reduce the frequency and severity of ifosfamide-induced nephrotoxicity, it appears that cumulative doses of 60 g/m should be considered carefully, especially in children <5 years of age.

Therapeutic approach to hypertension during pregnancy

QuestionQuite a few of my pregnant patients have hypertensive disorders. What is the threshold for treating hypertension during pregnancy? Which of the various antihypertensive agents are considered safe during pregnancy?AnswerPharmacologic therapy could benefit mother and baby when diastolic pressure exceeds 110 mm Hg. Preeclampsia must be followed closely. Methyldopa (eg, Aldomet) and hydralazine (eg, Apresoline) are still the drugs of choice during pregnancy, although the safety and efficacy of calcium channel blockers and Beta-blockers appear well established.

Managing exposure to chickenpox during pregnancy. New program

QUESTION

Every year several of my pregnant patients ask me what to do about being exposed to a child who later comes down with chickenpox. What is your recommendation?

ANSWER

Whether or not a mother had chickenpox in childhood often does not accurately determine her immunity. A rapid test, such as the latex agglutination test, is useful. If test results are negative, or if testing is not feasible, varicella zoster immunoglobulin should be administered within 96 hours of exposure.

Fetal alcohol syndrome. Role of the family physician

QuestionOne of my female patients drinks heavily. Although she is not planning to conceive, I worry that her lifestyle might lead to pregnancy and danger for her fetus. What do you recommend?AnswerYou should counsel your patient on effective contraception and advise her about the advantages of the various methods available.

Pharmacokinetic changes during pregnancy and their clinical relevance

The dynamic physiological changes that occur in the maternal-placental-fetal unit during pregnancy influence the pharmacokinetic processes of drug absorption, distribution and elimination. Pregnancy-induced maternal physiological changes may affect gastrointestinal function and hence drug absorption rates. Ventilatory changes may influence the pulmonary absorption of inhaled drugs. As the glomerular filtration rate usually increases during pregnancy, renal drug elimination is generally enhanced, whereas hepatic drug metabolism may increase, decrease or remain unchanged. A mean increase of 8 L in total body water alters drug distribution and results in decreased peak serum concentrations of many drugs. Decreased steady-state concentrations have been documented for many agents as a result of their increased clearance. Pregnancy-related hypoalbuminaemia, leading to decreased protein binding, results in increased free drug fraction. However, as more free drug is available for either hepatic biotransformation or renal excretion, the overall effect is an unaltered free drug concentration. Since the free drug concentration is responsible for drug effects, the above mentioned changes are probably of no clinical relevance. The placental and fetal capacity to metabolise drugs together with physiological factors, such as differences acid-base equilibrium of the mother versus the fetus, determine the fetal exposure to the drugs taken by the mother. As most drugs are excreted into the milk by passive diffusion, the drug concentration in milk is directly proportional to the corresponding concentration in maternal plasma. The milk to plasma (M:P) ratio, which compares milk with maternal plasma drug concentrations, serves as an index of the extent of drug excretion in the milk. For most drugs the amount ingested by the infant rarely attains therapeutic levels.

Acid-suppressing drugs during pregnancy

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Two cases of chlorinated hydrocarbon-associated myocardial ischemia

Chlorinated hydrocarbons are well known to produce ventricular arrhythmias because of myocardial sensitization to endogenous catecholamines, but cases of myocardial ischemia have not been described frequently. We report 2 cases of myocardial ischemia after exposure to chlorinated hydrocarbons. The first patient developed an asymptomatic myocardial infarction after inhalation of 1,1,1-trichloroethane at work. It is believed that 1,1,1-trichloroethane produced a coronary spasm that was sufficient to cause myocardial necrosis in the presence of coronary vessels already compromised by atherosclerosis. The second patient developed a reversible symptomatic myocardial ischemia of 4 h duration after chloral hydrate overdose. The evolution in both patients was favorable. Exposure to chlorinated hydrocarbons can be associated with myocardial ischemia particularly if the coronary circulation is already compromised.

Immune function in patients with beta thalassaemia receiving the orally active iron-chelating agent deferiprone

Short-term deferiprone may reduce body iron in some patients with thalassaemia major. Concerns regarding potential immunosuppressive effects of deferiprone have been raised from results of animal studies and case reports in humans. We studied immune function in 57 thalassaemia patients: 36 treated with deferiprone (L1; CP020) and 21 treated with desferrioxamine (DFO). Circulating B lymphocytes were increased in all patient groups. No differences were detected between treatment groups in percentages of circulating lymphocytes, concentrations of IgG, IgM or IgA, specific antibody titres, complement levels, or in vitro lymphocyte proliferation. No clinically important infections were observed in any patient. These data suggest that no clinical or laboratory changes consistent with immuno-suppression or immunodeficiency are observed during deferiprone therapy.

Pregnancy outcome and neurodevelopment of children exposed in utero to psychoactive drugs: the Motherisk experience

This paper presents an overview of the Motherisk Program data on pregnancy outcome and neurodevelopment of children exposed in utero to selected psychoactive drugs. First, the use of cocaine during pregnancy has been associated with increased risk of spontaneous abortions, abruptio placenta, premature labor, and stillbirth. Twenty-three adopted children exposed in utero to cocaine demonstrated an 8-fold increase in risk for microcephaly compared with controls. Global intelligence quotients (IQ) did not differ between the 2 groups, but the cocaine-exposed children achieved significantly lower scores on the Reynell language test. Second, the long-term neurobehavioral effects of fetal alcohol syndrome (FAS) were studied in 384 children to show that alcohol-induced brain insults, which consist of attention and memory deficits together, and poor adaptability and organization are not attenuated with age. Third, the rates of major malformations in children exposed in utero to fluoxetine, tricyclic antidepressants, and nonteratogenic drugs did not differ or exceed the expected rates in the general population. A 2nd phase of this study established the safety of antidepressants during pregnancy by demonstrating that the mean IQ and language scores are comparable in the 3 groups. A level 2 ultrasonography is recommended in cases of in utero exposure to lithium and carbamazepine because of an increased risk of cardiac malformations and spina bifida, respectively.