Drotaverine hydrochloride for augmentation of labor

OBJECTIVES

To study the use of drotaverine hydrochloride for acceleration of labor and relief of labor pains.

METHODS

In this double-blind placebo-controlled randomized study, 100 primigravidas in uncomplicated spontaneous labor at term were given drotaverine hydrochloride or placebo (distilled water) intramuscularly. Labor events, including pain (assessed by a visual analog scale and a verbal rating scale), neonatal outcome, and side effects of the drug were recorded. Student's t-test was used for analysis.

RESULTS

Forty-four patients in the drug group and 40 in the placebo group had complete data for analysis after decoding. In drotaverine group, there was a mean 15% reduction in the duration of the first stage of labor and a mean 19% reduction in the second stage. The maximum shortening of the first stage (28%) was observed when drotaverine was administered when cervical dilatation was 4 cm (P=0.044). There were no adverse fetal effects, but atonic postpartum hemorrhage was more common in the drotaverine group. There was no relief of pain with the drug except in the fourth stage of labor.

CONCLUSIONS

Drotaverine hydrochloride is safe and effective in accelerating labor, but not effective in lessening labor pain.

Effect of controlled-release oxybutynin on neurogenic bladder function in spinal cord injury

OBJECTIVE

This study evaluated the effects and tolerability of extended-release oxybutynin chloride on the frequency of voiding and catheterization and urodynamic capacity in spinal cord injury (SCI) patients with defined detrusor hyperreflexia.

METHODS

This was a 12-week, prospective, dose-titration study of extended-release oxybutynin (oxybutynin XL). SCI patients with urodynamically defined detrusor hyperreflexia were recruited for this study. Following a 7-day washout period, patients were evaluated via video-urodynamic study and then treatment was initiated at a dosage of 10 mg per day. Dosage was increased in weekly intervals to a maximum of 30 mg per day. Micturation frequency diaries and urodynamics were completed at baseline and repeated at week 12. Tolerability information was collected at each follow-up visit.

RESULTS

Ten patients (mean age = 49 years) with complete or incomplete SCI were enrolled. Participants reported clinical improvement (decreased urinary frequency and fewer incontinence episodes) with oxybutynin therapy following titration to 30 mg per day. All patients chose a final effective dosage of greater than 10 mg, with 4 patients taking the maximum of 30 mg per day. Mean cystometric bladder capacity increased from 274 mL to 380 mL (P = 0.008). No patient experienced serious adverse events during the 12-week study.

CONCLUSION

Oxybutynin XL is safe and effective in patients with detrusor hyperreflexia secondary to SCI. The onset of clinical efficacy occurs within 1 week, and daily dosages up to 30 mg are well tolerated.

The upregulation of type I plasminogen activator inhibitor in oral submucous fibrosis

Type I plasminogen activator inhibitor (PAI-1) is a 50 kDa glycoprotein belonging to the serine protease superfamily. PAI-1 is consistently and dramatically upregulated in a variety of fibrotic diseases. The aim of this study was to compare PAI-1 expression in normal human buccal mucosa and oral submucous fibrosis (OSF) specimens and further explore the potential mechanism that may lead to induced PAI-1 expression. Twenty-five OSF specimens and six normal buccal mucosa were examined by immunohistochemistry. The activity of PAI-1 from cells cultured from OSF and normal buccal mucosa were assayed using reverse-transcriptase polymerase chain reaction (RT-PCR) and Western blots. PAI-1 expression was significantly higher in OSF specimens and expressed mainly by fibroblasts, endothelial cells, and inflammatory cells. In addition, OSF exhibited higher PAI-1 expression than normal buccal mucosa fibroblast (BMF) both in mRNA and protein levels. To verify whether arecoline, a major areca nut alkaloid, could affect PAI-1 expression by human BMFs, RT-PCR and Western blots were used. The results demonstrated highly elevated PAI-1 mRNA and protein expression in normal human BMFs stimulated by arecoline. Taken together, these results suggest that PAI-1 expression is significantly upregulated in OSF tissues from areca quid chewers, and arecoline may be responsible for the enhanced PAI-1 expression in vivo.

Controlled, double-blind, multicentre clinical trial to investigate long-term tolerability and efficacy of trospium chloride in patients with detrusor instability

Our objectives were to ascertain the tolerability and efficacy of trospium chloride in doses of 20 mg twice daily for long-term therapy (52 weeks) in patients with urge syndrome. The trial comprised a total of 358 patients with urge syndrome or urge incontinence. After randomisation in the ratio of 3:1, participants were treated continuously for 52 weeks with either trospium chloride (20 mg twice daily) or oxybutynin (5 mg twice daily). At intervals of 4-8 weeks, patients were physically examined with measurements of blood pressure and pulse rate, were questioned about any adverse events, checked for compliance and underwent relevant laboratory tests. As an additional safety measure, an ECG was made at 26 and 52 weeks. Urodynamic measurements were performed at the beginning, and at 26 and 52 weeks to determine the maximal cystometric bladder capacity. Among others things, the frequencies of micturition, incontinence and number of urgency events were recorded in patient diary protocols in weeks 0, 2, 26 and 52. The evaluation of vital parameters, laboratory results and ECGs did not show any relevant changes attributable to the action of the anticholinergics. Analysis of the micturition diary clearly indicated a reduction of the micturition frequency, incontinence frequency, and a reduction of the number of urgencies in both treatment groups. Mean maximum cystometric bladder capacity increased during treatment with trospium chloride by 92 ml after 26 weeks and 115 ml after 52 weeks (P=0.001). Further comparison with oxybutynin did not reveal any statistically significant differences in urodynamic variables between the drugs. Adverse events occurred in 64.8% of the patients treated with trospium chloride and 76.7% of those treated with oxybutynin. The main symptom encountered in both treatment group was dryness of the mouth. For patients on trospium chloride, the estimated risk of an unexpected adverse event was 0.027 per patient per week for all adverse events and 0.009 for dryness of the mouth, resulting in a considerably lower risk during treatment given with trospium chloride than with oxybutynin (0.045 and 0.021, respectively). An overall assessment for each of the drugs reveals a comparable efficacy level and a better benefit-risk ratio for trospium chloride than for oxybutynin due to better tolerability.

[The elderly patient with urge incontinence or urge-stress incontinence - efficacy and cardiac safety of propiverine]

PURPOSE

The efficacy of propiverine in elderly patients suffering from urge incontinence or urge-stress incontinence was intended to be investigated. Especially in elderly patients a cardiac influence of propiverine is possible due to its dual mode of action. That is why besides the efficacy especially the cardiac safety was intended to be investigated.

MATERIAL AND METHODS

Ninety-eight patients (21 male, 77 female; 67.7 +/- 6.3 years of age) suffering from urgency, urge incontinence or mixed urge-stress incontinence were included in the double-blind, multicentre, placebo-controlled, randomized study. After a two-week placebo run-in period, the patients received propiverine (15 mg t. i. d.) or placebo (t. i. d.) for four weeks. Before (U 1, U 2) and during the treatment period (U 3, U 4), standard ECG's and 24 h long-term ECG's were recorded.

RESULTS

Propiverine caused a significant reduction in the micturition frequency (U 2 : 8.7 +/- 4.2, U 4 : 6.5 +/- 3.2 ml; p < 0.01) reflected in a significant increase in the average micturition volume (U 2 : 163.5 +/- 65.9, U 4 : 216.3 +/- 101.5 ml; p < 0.01) and a significant reduction in the episodes of incontinence (- 54 %; p < or = 0.05). These findings were confirmed by the overall assessment after four weeks in which approximately 90 % of patients under propiverine were either free from urge incontinence and urge symptoms or improved. The efficacy parameters demonstrated a better efficacy for urge incontinence than for mixed urge-stress incontinence. Resting and ambulatory electrocardiograms evidenced no significant changes. Neither QTc interval nor other cardiac parameters were relevantly altered. The frequency of cardiac events (Lown classes IV a/b) was fortuitous, revealing no difference between placebo and propiverine. The incidence of adverse events was very low (2 % dryness of the mouth under propiverine) and confirmed by the findings from the quality of life questionnaires.

CONCLUSIONS

A favourable benefit-risk ratio in the treatment of elderly patients suffering from urgency, urge incontinence or combined urge-stress incontinence is therefore proven for propiverine. Cardiac arrhythmia were not induced.

Use of atropine in patients with submaximal heart rate during exercise myocardial perfusion SPECT

BACKGROUND

Failure to reach 85% of maximal predicted heart rate (MPHR) during exercise may render a myocardial perfusion single photon emission computed tomography (MPS) study nondiagnostic for ischemia detection. Although commonly used to increase heart rate (HR) during dobutamine stress, the administration of atropine for patients failing to achieve 85% of MPHR during exercise performed for MPS is still infrequent.

METHODS AND RESULTS

Patients undergoing dual-isotope MPS were considered candidates for the study when, during exercise treadmill testing, they had less than 85% of MPHR and were unable to continue because of fatigue, without an ischemic response. Forty-seven patients (aged 65.3 +/- 12.5 years, 78.7% men) received atropine (0.6-1.2 mg). Maximal HR achieved before and after atropine was 118.0 +/- 14.8 beats/min (76.3% +/- 6.2% of MPHR) and 146.4 +/- 12.6 beats/min (94.4% +/- 8.1% of MPHR), respectively (P < .001). Of patients, 44 (93.6%) reached at least 85% of MPHR after atropine and had diagnostic MPS studies. After atropine, arrhythmias occurred in 14 patients (29.8%) and other minor side effects in 1 (2.1%).

CONCLUSIONS

Atropine allows patients initially failing to achieve 85% of MPHR during exercise to increase HR and have a diagnostic MPS study, without major complications. It may provide an alternative to pharmacologic stress for patients with a blunted HR response to exercise.

A benefit-risk assessment of extended-release oxybutynin

Oxybutynin is a muscarinic receptor antagonist, which has been available for a number of years in its original immediate-release (IR) formulation. While oxybutynin IR has proven effective for the treatment of overactive bladder, its extended use can be limited by adverse effects, particularly dry mouth. An extended-release (ER) formulation of oxybutynin based on the OROS system has recently become available, which allows once daily administration. In direct comparison to oxybutynin IR, oxybutynin ER has an increased oral bioavailability for the parent compound oxybutynin which is accompanied by a reduced bioavailability for the active metabolite N-desethyl-oxybutynin. The latter has been implicated in mediating a major part of the adverse effects of oxybutynin treatment. Two double-blind, placebo-controlled, randomised studies in patients with overactive bladder have demonstrated that oxybutynin ER has a similar efficacy as oxybutynin IR but with improved tolerability. This is in line with clinical pharmacological studies demonstrating a smaller impairment of saliva production with oxybutynin ER than with oxybutynin IR. Thus, the ER formulation of oxybutynin maintains the therapeutic benefits and concomitantly improves tolerability.

Generalized tetany: an unusual complication during dobutamine stress echocardiography

Dobutamine stress echocardiography is a frequently used noninvasive method for the evaluation of inducible myocardial ischemia, myocardial viability, and preoperative cardiac risk. Although its clinical safety has been validated, side effects and complications especially with the coadministration of atropine can occur. We report a case of generalized tetany in a 49-year-old woman undergoing dobutamine stress echocardiography.

Hymecromone in the treatment of motor disorders of the bile ducts: a multicenter, double-blind, placebo-controlled clinical study

Biliary dyskinesia is frequently encountered in clinical practice and is characterized by pain during or after meals. The present study was designed to assess the action of hymecromone in patients with motor disorders of the bile ducts. One hundred twenty-three patients (36 men and 87 women) were enrolled in the multicenter double-blind placebo-controlled study. The mean age was 60.3 years +/- 14.2 SD. Diagnosis was dyspepsia in 58 patients, dyskinesia in 59, cholelithiasis in five and hepatopathy in one. The patients were divided into two groups. One group (61 patients) was treated with hymecromone (300 mg tablets at a dosage of 1,200 mg/day, 2 tablets midday and evening) and another group (62 patients) was treated with placebo. Treatment lasted for 14 days. Control of dyspepsia and pain symptoms of biliary origin was more marked and constant with hymecromone than with placebo. By the end of the treatment, patients in the hymecromone group showed a 70.3% reduction in intensity of spontaneous abdominal pain, while the placebo group showed a 43.8% reduction. Hymecromone was well accepted by the patients and judged to be effective by the investigator in 88.5% of patients treated. The possibility of using hymecromone in 300-mg tablets in the treatment of motor disorders of the bile ducts is thus confirmed.

Trospium chloride in patients with detrusor overactivity: meta-analysis of placebo-controlled, randomized, double-blind, multi-center clinical trials on the efficacy and safety of 20 mg trospium chloride twice daily

OBJECTIVES

Primary objective of this meta-analysis was to produce a systematic and quantitative review of two independent clinical trials of 20 mg trospium chloride (TCI) twice daily (b.i.d.) in patients with detrusor overactivity [Alloussi et al. 1998, Cardozo et al. 2000].

PATIENTS AND METHODS

In two placebo-controlled, double-blind, multi-center studies, the effect of TCl on detrusor function was evaluated using urodynamic measurements. All 517 patients were randomized to receive TCl or placebo for 3 weeks. Urodynamic variables were measured at the beginning and at the end of the treatment. Safety was evaluated on the basis of adverse events (AEs), vital signs and laboratory tests.

RESULTS

TCl produced significant improvements in 'maximum cystometric bladder capacity' (median treatment effect = 52 ml, 95% confidence interval 32-71 ml, p<0.0001) and 'urinary volume at first unstable contraction' (median treatment effect = 48 ml, 95% confidence interval 28 to 68 ml, p = 0.0001). The patients' assessment of efficacy also showed significantly greater clinical improvement in the TCl group than in the placebo group (p < 0.0001). The patients recorded a 'cure' or a 'marked improvement' more often in the TCl group than in the placebo group (47.9% and 19.7%, respectively). TCl was well tolerated, with similar frequencies of AEs reported in both groups (TCl: 35.7%, placebo group: 38.9%).

CONCLUSIONS

Trospium chloride (20 mg twice daily) is an effective and safe medication for the treatment of detrusor overactivity.

Effects of 10 mg and 15 mg oral procyclidine on critical flicker fusion threshold and cardiac functioning in healthy human subjects

The critical flicker fusion threshold (CFFT) is thought to index alertness and cortical arousal. Sedative drugs reduce CFFT while psychostimulants increase it. Procyclidine is an anticholinergic that is used to control the extrapyramidal side-effects of antipsychotics in schizophrenia. This study examined the effects of clinically relevant doses of oral procyclidine administration on CFFT and heart rate in two separate experiments (Experiment 1, drug dose: 10 mg, n = 16; Experiment 2, drug dose: 15 mg, n = 12) involving healthy subjects using a double-blind, placebo-controlled, cross-over design. 10 mg procyclidine had no significant effect on CFFT, heart rate or self-ratings of mood, but the 15 mg dose significantly lowered CFFT at 1 h and 2 h after procyclidine administration, increased drowsiness ratings and produced a drop in heart rate. The effects observed in this study may have implications for treatment compliance of schizophrenic patients, choice of antipsychotics, prescribing to patients with heart disease and monitoring of cardiac function under treatment. Further investigations are required to quantify the effects of procyclidine on CFFT and cardiac function in patients with schizophrenia.

Antispasmodic/analgesic associations in primary dysmenorrhea double-blind crossover placebo-controlled clinical trial

We studied 125 patients with primary dysmenorrhea in a prospective randomized double-blind crossover study. After an admission pretreatment period without medication, the patients completed three consecutive randomized treatment phases with lysine clonixinate 125 mg plus propinox 10 mg or paracetamol 500 mg plus hyoscine N-butylbromide 10 mg or placebo, according to a fixed-dose schedule of 1 tablet every 6 h, 3 days before onset of menses and for 5 days thereafter. Changes in menstrual pain intensity and duration, amount of bleeding measured according to the number of daily pads used and concomitant symptoms were assessed on the fifth day of each cycle. Every night, the patients recorded the average intensity of menstrual pain during the first 4 days of menstruation in a diary The follow-up visit carried out at day 5 showed significant reduction in pain intensity with both active treatments vs. the other two phases: baseline: 2.72 +/- 0.61; placebo: 1.85 +/- 0.87; lysine clonixinate plus propinox 1.36 +/- 0.81, and paracetamol plus hyosine N-butylbromide: 1.45 +/- 0.87. The patients' diaries showed increasingly lower pain intensities starting from day 1 with the three treatments. Active treatments revealed significantly higher analgesic efficacy from the outset compared with baseline and placebo; however, only the lysine clonixinate plus propinox combination reached a statistically significant difference by days 3 and 4. No changes in duration or intensity of menstrual bleeding or in the incidence of adverse effects were observed during the four study periods.

[Safety profile of NO-SPA]

The aim of the safety analysis performed by Chinoin Drug Safety Unit was to summarise the safety profile of NO-SPA (drotaverine hydrochloride), the Hungarian spasmolytic well known in Hungary and abroad. Authors collected the safety data from clinical studies between 1964-1998 for the determination of the adverse event frequency. Based on the data of 12111 patients treated with NO-SPA in 37 clinical trials 0.9% frequency of adverse events was found. The value indicates uncommon (0.1-1%) adverse event frequency according to the criteria for frequency categories. The benefit-risk ratio of NO-SPA is favourable, since the therapeutic effect does not include frequent adverse reaction occurrence.

Central anticholinergic syndrome in a child undergoing circumcision

We describe one of the few pediatric cases of central anticholinergic syndrome (CAS) in an 8-year-old boy undergoing elective surgery. Deep sedation, inadequate response to stimuli and reduced muscular tone of the upper airway resulting in airway obstruction were the clinical manifestations of CAS. The symptoms resolved immediately after administration of physostigmine. This case illustrates the importance of considering central anticholinergic syndrome as a differential diagnosis in children if prolonged sedation after general anesthesia occurs.

Urinary antispasmodic use and the risks of ventricular arrhythmia and sudden death in older patients

OBJECTIVES

The introduction of new medications to treat overactive bladder has resulted in a significant increase in the number of individuals with this condition who use medications for symptoms. Formal epidemiological studies of the safety of these medications in typical patient populations are lacking, particularly studies of serious events. We sought to determine whether the use of urinary antispasmodics increases the risk of ventricular arrhythmias or sudden death.

DESIGN

Retrospective cohort study.

SETTING

Retrospective analysis of data of participants in community, hospital or nursing home setting.

PARTICIPANTS

Fourteen thousand six hundred thirty-eight subjects with a diagnosis of urinary incontinence made between January 1, 1991, and June 30, 1995; all were aged 65 and older and enrolled in Medicare and Medicaid or the Pharmacy Assistance for the Aged and Disabled programs of New Jersey.

MEASUREMENTS

Filled prescriptions for oxybutynin (Ditropan), flavoxate (Urispas), hyoscyamine (Cystospas), and hyoscyamine sulfate (Cystospas-M) were used to define days of exposure to these drugs. We also identified all use of nonsedating antihistamines and cytochrome P450 3A4 inhibitors, and their concurrent use, to serve as a positive control exposure. Two outcomes were then defined: a new diagnosis of ventricular arrhythmia combined with initiation of an antiarrhythmic medication and sudden death. Other covariates, including clinical, demographic, medication use, and healthcare utilization variables, were also assessed. Adjusted risk ratios of ventricular arrhythmia and sudden death were derived from multivariable Cox proportional hazards models.

RESULTS

There was no significant association between periods of use of urinary antispasmodics and the development of ventricular arrhythmias (adjusted risk ratio (RR) = 1.23, 95 confidence interval (CI) = 0.87-1.75) or sudden death (adjusted RR = 0.70, 95% CI = 0.28-1.74). A significantly increased risk of ventricular arrhythmia was observed for the positive control regimen, concurrent use of nonsedating antihistamines and cytochrome P450 3A4 inhibitors (adjusted RR = 5.47; 95% CI = 1.34-22.26), but not for use of either drug group alone. Concurrent use of nonsedating antihistamines and cytochrome P450 3A4 inhibitors was also associated with a significant increase in the risk of sudden death (adjusted RR = 21.50, 95% CI = 5.23-88.37). Other variables significantly associated with ventricular arrhythmia included ischemic heart disease and congestive heart failure, whereas nursing home use before the index date was associated with a decreased likelihood of receiving a diagnosis of and treatment for ventricular arrhythmia. Other variables significantly associated with sudden death included male gender, black race, and congestive heart failure.

CONCLUSIONS

Antimuscarinic urinary antispasmodics available before 1996 were not associated with an increased risk of ventricular arrhythmias and sudden death. Additional study will be required to confirm these results, exclude the possibility of unmeasured confounders contributing to any lack of an observed relationship, and extend these findings to newer agents such as tolterodine.

Safety and efficacy of glucagon as a premedication for upper gastrointestinal endoscopy--a comparative study with butyl scopolamine bromide

BACKGROUND

Glucagon inhibits digestive motility and is used for endoscopic premedication; however, its effect on cardiopulmonary function during endoscopy has not yet been fully investigated.

AIM

To clarify the efficacy and safety of glucagon compared with butyl scopolamine bromide as upper gastrointestinal endoscopy premedication.

METHODS

Two hundred and forty consecutive patients over 40 years of age, referred for upper gastrointestinal endoscopy, without any complications, were studied. These patients were randomly premedicated with butyl scopolamine bromide (SC group) or glucagon (G group). Time course changes in blood pressure, arterial oxygen saturation, heart rate and the number of retching episodes during endoscopy were examined. The efficacy of glucose tablets after upper gastrointestinal endoscopy to prevent hypoglycaemia caused by glucagon was evaluated. Cardiopulmonary parameters were also examined in 77 complicated patients with glucagon premedication (GC group).

RESULTS

A continuous increase in heart rate during upper gastrointestinal endoscopy was observed in the SC group, but not in the G and GC groups. Blood pressure, arterial oxygen saturation and number of retching episodes were not different between the groups. Hypoglycaemia-related symptoms were frequent in the G group without glucose tablets, but were prevented by the administration of glucose.

CONCLUSIONS

Glucagon has a weaker effect on cardiopulmonary function during upper gastrointestinal endoscopy than butyl scopolamine bromide. Glucose administration prevents hypoglycaemia-related symptoms caused by glucagon.

Validation of a stable isotope gastric emptying test for normal, accelerated or delayed gastric emptying

To validate a 13C-Spirulina platensis breath test for measurement of accelerated or delayed gastric emptying, we measured gastric emptying of egg containing 13C-S. platensis and 99mTc-sulphur colloid by breath 13 CO2 every 15 min over 3 h and scintigraphy every 15-30 min over 5 h in 57 healthy volunteers. Thirty-three received no treatment, 10 received erythromycin, and 14 atropine. A generalized linear regression model predicted half-emptying time by scintigraphy (t1/2S) from breath 13CO2 (t1/2B) data. Accuracy was assessed by standard deviation (SD) of differences between t1/2S and t1/2B and by receiver operating characteristic (ROC) curves. Regression models using breath samples at baseline, and 45, 90, 105 and 120 min, predicted t1/2B (mean +/- SD) at 118 +/- 59 min, similar to t1/2S (118 +/- 67 min). Correlation between t1/2B and t1/2S was significant (r=0.88; P < 0.0001). Differences between t1/2S and t1/2B were: 18-19.2 min for t1/2 < 70-150 min, and 68.3 min for t1/2 > 150 min. Breath test detected abnormal emptying with a sensitivity of 86% and specificity of 80%. Thus, the 13C-S. platensis test measures gastric emptying t1/2 for solids, which is accelerated or delayed to mimic a range of conditions from dumping syndrome to severe gastroparesis, with high sensitivity and specificity. Additional breath samples are needed to increase sensitivity in detecting accelerated gastric emptying.

Antiapoptotic effect of dipyrone on HL-60, Jurkat and Raji cell lines submitted to UV irradiation, arachidonic acid and cycloheximide treatments

The effect of dipyrone (metamizol) on cell viability was evaluated in human leukocyte cell lines upon different apoptotic treatments: arachidonic acid (AA), cycloheximide (CHX), tumor necrosis factor (TNF) and ultraviolet (UV) irradiation. Dipyrone had a dual effect: at high concentrations (beyond 300 microM), it was cytotoxic, leading to apoptosis, whereas at lower concentrations (37.5-300 microM), it was cytoprotective, delaying the loss of membrane integrity triggered by arachidonic acid (100-200 microM) and UV irradiation and the cytotoxicity of cycloheximide (25-50 microM). No effect of dipyrone was found on TNF-induced cytotoxicity (250 ng/ml). The cytoprotective effect of dipyrone is associated with a decrease in DNA fragmentation, as assessed by electrophoresis of genomic DNA and by flow cytometry; a reduction in the percentage of condensed nuclei, as evaluated by DNA staining with Hoescht 33342 and a decrease in poly(ADP)-ribose polymerase (PARP) cleavage, as assessed by Western blotting. The cytoprotective effect of dipyrone on leukocyte apoptosis occurs at concentrations usually found for the main active metabolite of the drug and may have implications on the therapeutic and side effects caused by this agent.

Effects of tolterodine, trospium chloride, and oxybutynin on the central nervous system

Antimuscarinic compounds are increasingly used to treat the symptoms of overactive bladder; however, their use is often restricted by peripheral adverse effects (AEs). On the other hand, data regarding their influence on the central nervous system (CNS) are limited. This randomized, single-blind, parallel-group quantitative-topographical EEG (qEEG) study of clinical phase I investigates the potential CNS adverse effects of the three antimuscarinic drugs--tolterodine, oxybutynin, and trospium chloride--in comparison to placebo. Overall, 4 x 16 (total 64) young, healthy male volunteers were included in the study. The subjects were given either placebo or the clinically recommended daily doses of the drugs dispensed in three doses on a single day (tolterodine 2 mg bid and once placebo, total 4 mg/d; oxybutynin 5 mg tid, total 15 mg/d; and trospium chloride 15 mg tid, total 45 mg/d). The qEEG was recorded prior to and up to 4 hours after each intake of the trial medication (a total of 10 qEEG sessions) under three different conditions: at rest with eyes open, eyes closed, and under mental demand. The drug tolerability was subjectively evaluated by the volunteer and the investigator. In comparison to placebo (10% confidence interval), tolterodine and trospium chloride did not induce changes of the qEEG power in five of the six frequency bands (i.e., delta, alpha 1, alpha 2, beta 1, and beta 2). Isolated power decreases were only observed in the theta frequency band. In contrast, oxybutynin caused significant power reductions in four frequency bands (theta, alpha 1, alpha 2, and beta 1; p < 0.01). The subjectively evaluated drug tolerability was comparable between all treatment groups, although differences in the AE occurrence existed, with the AE frequency being higher in the oxybutynin group. The results of this study support the findings that oxybutynin as a tertiary amine crosses the blood-brain barrier, causing significant qEEG activity changes and more pronounced central adverse effects. Although tolterodine is also a tertiary amine, it shows limited effects on qEEG activity (i.e., slight theta power reductions), comparable to the effects of trospium chloride, a quarternary amine, which barely crosses the blood-brain barrier. The minimal qEEG changes observed with tolterodine and trospium chloride reflect most probably a rebound message from the peripheral target organs. Prescription of oxybutynin thus implicates a higher risk of CNS side effects.