Propensity For Interactions Research Articles

Eprosartan

Eprosartan is an angiotensin II receptor antagonist (angiotensin II receptor blocker [ARB]) used in the treatment of hypertension. In large, randomized trials, eprosartan (with or without hydrochlorothiazide [HCTZ]) demonstrated superior antihypertensive efficacy to that of placebo and, when administered at comparable dosage regimens, had similar blood pressure-lowering effects to enalapril. Eprosartan was generally well tolerated in clinical trials and had a lower incidence of persistent dry cough than enalapril. Eprosartan has a neutral effect on metabolic parameters, such as serum lipid levels and glucose homeostasis, and a low propensity for pharmacokinetic drug interactions. The use of eprosartan or other ARBs in combination with HCTZ tends to reverse the potassium loss associated with thiazide diuretics. Independent of its antihypertensive effects, eprosartan was associated with improved clinical outcomes (primary composite endpoint of all causes of mortality and all cardiovascular and cerebrovascular events, including all recurrent events) compared with nitrendipine in a randomized, secondary prevention trial in hypertensive patients with previous cerebrovascular events (MOSES trial). Eprosartan also reduced blood pressure and was associated with a modest improvement in cognitive function in a large observational study in patients > or =50 years of age with newly diagnosed hypertension (OSCAR study). In both of these trials, additional antihypertensive therapy, such as HCTZ, was permitted. Therefore, eprosartan is a useful treatment option in the management of a broad range of patients with hypertension, and its use with HCTZ provides a rational combination regimen.

Pharmacokinetic Evaluation of Rifabutin in Combination with Lopinavir‐Ritonavir in Patients with HIV Infection and Active Tuberculosis

Human immunodeficiency virus (HIV)-associated tuberculosis is difficult to treat, given the propensity for drug interactions between the rifamycins and the antiretroviral drugs. We examined the pharmacokinetics of rifabutin before and after the addition of lopinavir-ritonavir. We analyzed 10 patients with HIV infection and active tuberculosis in a state tuberculosis hospital. Plasma was collected for measurement of rifabutin, the microbiologically active 25-desacetyl-rifabutin, and lopinavir by validated high-performance liquid chromatography assays. Samples were collected 2-4 weeks after starting rifabutin at 300 mg thrice weekly without lopinavir-ritonavir, 2 weeks after the addition of lopinavir-ritonavir at 400 and 100 mg, respectively, twice daily to rifabutin at 150 mg thrice weekly, and (if rifabutin plasma concentrations were below the normal range) 2 weeks after an increase in rifabutin to 300 mg thrice weekly with lopinavir-ritonavir. Noncompartmental and population pharmacokinetic analyses (2-compartment open model) were performed. Rifabutin at 300 mg without lopinavir-ritonavir produced a low maximum plasma concentration (C(max)) in 5 of 10 patients. After the addition of lopinavir-ritonavir to rifabutin at 150 mg, 9 of 10 had low C(max) values. Eight patients had dose increases to 300 mg of rifabutin with lopinavir-ritonavir. Most free rifabutin (unbound to plasma protein) C(max) values were below the tuberculosis minimal inhibitory concentration. For most patients, values for the area under the plasma concentration-time curve were as low or lower than those associated with treatment failure or relapse and with acquired rifamycin resistance in Tuberculosis Trials Consortium/US Public Health Service Study 23. One of the 10 patients experienced relapse with acquired rifamycin resistance. The recommended rifabutin doses for use with lopinavir-ritonavir may be inadequate in many patients. Monitoring of plasma concentrations is recommended.

Milnacipran

Milnacipran is a serotonin and norepinephrine reuptake inhibitor (SNRI) with negligible effects on any presynaptic or postsynaptic receptors. Milnacipran has unique pharmacokinetic and pharmacodynamic characteristics that distinguish it from the other marketed serotonin and norepinephrine reuptake inhibitors, venlafaxine, desvenlafaxine, and duloxetine such as equipotent serotonin and norepinephrine reuptake inhibition and a linear dose-concentration trend at therapeutic doses. The half-life of milnacipran is approximately 8 hours. In addition, milnacipran does not inhibit the cytochrome P 450 system, indicating minimal propensity for drug-drug interactions. The antidepressant efficacy of milnacipran has been clearly established in a number of randomized, double-blind, placebo-controlled clinical trials, and it has been widely used for treating major depressive disorder. Moreover, evidence suggests that milnacipran is effective and tolerable in the treatment of fibromyalgia and may have usefulness for fatigue and anxiety symptoms. The current paper reviews researches conducted to date that is relevant to the efficacy, tolerability, and mechanism of action of milnacipran in the treatment of depression, fibromyalgia, and other psychiatric syndromes. Future directions of research are also identified.

Prediction of small molecule binding property of protein domains with Bayesian classifiers based on Markov chains

Accurate computational methods that can help to predict biological function of a protein from its sequence are of great interest to research biologists and pharmaceutical companies. One approach to assume the function of proteins is to predict the interactions between proteins and other molecules. In this work, we propose a machine learning method that uses a primary sequence of a domain to predict its propensity for interaction with small molecules. By curating the Pfam database with respect to the small molecule binding ability of its component domains, we have constructed a dataset of small molecule binding and non-binding domains. This dataset was then used as training set to learn a Bayesian classifier, which should distinguish members of each class. The domain sequences of both classes are modelled with Markov chains. In a Jack-knife test, our classification procedure achieved the predictive accuracies of 77.2% and 66.7% for binding and non-binding classes respectively. We demonstrate the applicability of our classifier by using it to identify previously unknown small molecule binding domains. Our predictions are available as supplementary material and can provide very useful information to drug discovery specialists. Given the ubiquitous and essential role small molecules play in biological processes, our method is important for identifying pharmaceutically relevant components of complete proteomes. The software is available from the author upon request.

Surface Modification of PLGA Particles: The Interplay between Stabilizer, Ligand Size, and Hydrophobic Interactions

Therapeutic and diagnostic carriers can be functionalized with active targeters to induce tissue-specific delivery. However, the possible impact of adsorbed steric stabilizer such as the frequently used poloxamers (Pluronics) on surface modification of poly(D,L-lactide-co-glycolide) (PLGA) particles has not been examined so far. Therefore, three model ligands of different molecular weights (653; 36,000; 155,000 g/mol) covering the size range of important targeters were conjugated to the surface of PLGA microparticles in the presence of different concentrations of Pluronic F68 (0.01-5%, w/v). Flow cytometry and fluorimetric quantification revealed for all tested ligands that high Pluronic concentrations decreased the coupling efficiency to a half or even one-third of that achieved in the absence of stabilizer. Moreover, the reduction strongly depends on the ligand size and its propensity for hydrophobic interactions. Apart from that, a high degree of particle aggregation was observed with Pluronic concentrations below 0.1% (w/v). Thus, a compromise has to be found, which combines sufficient stability with the best possible ligand coupling efficiency. For the studied system, 0.1% (w/v) turned out to be the optimum concentration of Pluronic F68.

Analysis of the Dynamics of Assembly and Structural Impact for a Histidine Tagged FGF1−1.5 nm Au Nanoparticle Bioconjugate

Whether assembling proteins onto nanoscale, mesoscopic, or macroscropic material surfaces, maintaining a protein's structure and function when conjugated to a surface is complicated by the high propensity for electrostatic or hydrophobic surface interactions and the possibility of direct metal coordination of protein functional groups. In this study, the assembly of a 1.5 nm CAAKA passivated gold nanoparticle (AuNP) onto FGF1 (human acidic fibroblast growth factor) using an amino terminal His(6) tag is analyzed. The impact of structure and time-dependent changes in the structural elements in FGF1and FGF1-heparin in the presence of the AuNP is probed by a molecular beacon fluorescence assay, circular dichroism, and NMR spectroscopy. Analysis of the results indicates that a time-dependent evolution of the protein structure without loss of FGF1 heparin binding occurs following the formation of the initial FGF1-AuNP complex. The time-dependent changes are believed to reflect protein sampling of the AuNP surface to minimize the free energy of the AuNP-FGF1 complex without impacting FGF1 function.

EasyMIFs and SiteHound: a toolkit for the identification of ligand-binding sites in protein structures

SiteHound uses Molecular Interaction Fields (MIFs) produced by EasyMIFs to identify protein structure regions that show a high propensity for interaction with ligands. The type of binding site identified depends on the probe atom used in the MIF calculation. The input to EasyMIFs is a PDB file of a protein structure; the output MIF serves as input to SiteHound, which in turn produces a list of putative binding sites. Extensive testing of SiteHound for the detection of binding sites for drug-like molecules and phosphorylated ligands has been carried out. EasyMIFs and SiteHound executables for Linux, Mac OS X, and MS Windows operating systems are freely available for download from http://sitehound.sanchezlab.org/download.html. Supplementary data are available at Bioinformatics online.

Malleable Machines in Transcription Regulation: The Mediator Complex

The Mediator complex provides an interface between gene-specific regulatory proteins and the general transcription machinery including RNA polymerase II (RNAP II). The complex has a modular architecture (Head, Middle, and Tail) and cryoelectron microscopy analysis suggested that it undergoes dramatic conformational changes upon interactions with activators and RNAP II. These rearrangements have been proposed to play a role in the assembly of the preinitiation complex and also to contribute to the regulatory mechanism of Mediator. In analogy to many regulatory and transcriptional proteins, we reasoned that Mediator might also utilize intrinsically disordered regions (IDRs) to facilitate structural transitions and transmit transcriptional signals. Indeed, a high prevalence of IDRs was found in various subunits of Mediator from both Saccharomyces cerevisiae and Homo sapiens, especially in the Tail and the Middle modules. The level of disorder increases from yeast to man, although in both organisms it significantly exceeds that of multiprotein complexes of a similar size. IDRs can contribute to Mediator's function in three different ways: they can individually serve as target sites for multiple partners having distinctive structures; they can act as malleable linkers connecting globular domains that impart modular functionality on the complex; and they can also facilitate assembly and disassembly of complexes in response to regulatory signals. Short segments of IDRs, termed molecular recognition features (MoRFs) distinguished by a high protein–protein interaction propensity, were identified in 16 and 19 subunits of the yeast and human Mediator, respectively. In Saccharomyces cerevisiae, the functional roles of 11 MoRFs have been experimentally verified, and those in the Med8/Med18/Med20 and Med7/Med21 complexes were structurally confirmed. Although the Saccharomyces cerevisiae and Homo sapiens Mediator sequences are only weakly conserved, the arrangements of the disordered regions and their embedded interaction sites are quite similar in the two organisms. All of these data suggest an integral role for intrinsic disorder in Mediator's function.

Evidence for a Coiled-coil Interaction Mode of Disordered Proteins from Bacterial Type III Secretion Systems

Gene clusters encoding various type III secretion system (T3SS) injectisomes, frequently code downstream of the conserved atpase gene for small hydrophilic proteins whose amino acid sequences display a propensity for intrinsic disorder and coiled-coil formation. These properties were confirmed experimentally for a member of this class, the HrpO protein from the T3SS of Pseudomonas syringae pv phaseolicola: HrpO exhibits high alpha-helical content with coiled-coil characteristics, strikingly low melting temperature, structural properties that are typical for disordered proteins, and a pronounced self-association propensity, most likely via coiled-coil interactions, resulting in heterogeneous populations of quaternary complexes. HrpO interacts in vivo with HrpE, a T3SS protein for which coiled-coil formation is also strongly predicted. Evidence from HrpO analogues from all T3SS families and the flagellum suggests that the extreme flexibility and propensity for coiled-coil interactions of this diverse class of small, intrinsically disordered proteins, whose structures may alter as they bind to their cognate folded protein targets, might be important elements in the establishment of protein-protein interaction networks required for T3SS function.

Prokaryotic Gene Finding Based on Physicochemical Characteristics of Codons Calculated from Molecular Dynamics Simulations

An ab initio model for gene prediction in prokaryotic genomes is proposed based on physicochemical characteristics of codons calculated from molecular dynamics (MD) simulations. The model requires a specification of three calculated quantities for each codon: the double-helical trinucleotide base pairing energy, the base pair stacking energy, and an index of the propensity of a codon for protein-nucleic acid interactions. The base pairing and stacking energies for each codon are obtained from recently reported MD simulations on all unique tetranucleotide steps, and the third parameter is assigned based on the conjugate rule previously proposed to account for the wobble hypothesis with respect to degeneracies in the genetic code. The third interaction propensity parameter values correlate well with ab initio MD calculated solvation energies and flexibility of codon sequences as well as codon usage in genes and amino acid composition frequencies in ∼175,000 protein sequences in the Swissprot database. Assignment of these three parameters for each codon enables the calculation of the magnitude and orientation of a cumulative three-dimensional vector for a DNA sequence of any length in each of the six genomic reading frames. Analysis of 372 genomes comprising ∼350,000 genes shows that the orientations of the gene and nongene vectors are well differentiated and make a clear distinction feasible between genic and nongenic sequences at a level equivalent to or better than currently available knowledge-based models trained on the basis of empirical data, presenting a strong support for the possibility of a unique and useful physicochemical characterization of DNA sequences from codons to genomes.

The use of fluvastatin in cardiovascular risk management

Background: Fluvastatin was the first synthetic 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin) to be developed and is used in the management of dyslipidaemia in primary and secondary prevention of cardiovascular disease. Objective: This article reviews the properties of fluvastatin and experience accrued through its use in clinical practice and clinical trials. Methods: Relevant publications were identified through the PubMed database and product information held by the US Federal Drug Administration was also reviewed. Results/conclusions: In the authors' opinion, fluvastatin exhibits a favourable safety profile in comparison to other statins, with a low incidence of adverse effects and a reduced propensity for interactions with other drugs. However, fluvastatin is a less potent cholesterol-lowering agent than newer statins on the market and its future predominant use is likely to be in niche patient groups at risk of side effects or drug interactions with other agents.

Halogenated ligands and their interactions with amino acids: Implications for structure–activity and structure–toxicity relationships

The properties of chemicals are rooted in their molecular structure. It follows that structural analysis of specific interactions between ligands and biomolecules at the molecular level is invaluable for defining structure–activity relationships (SARs) and structure–toxicity relationships (STRs). This study has elucidated the structural and molecular basis of interactions of biomolecules with alkyl and aryl halides that are extensively used as components in many commercial pesticides, disinfectants, and drugs. We analyzed the protein structures deposited in Protein Data Bank (PDB) for structural information associated with interactions between halogenated ligands and proteins. This analysis revealed distinct patterns with respect to the nature and structural characteristics of halogen interactions with specific types of atoms and groups in proteins. Fluorine had the highest propensity of interactions for glycine, while chlorine for leucine, bromine for arginine, and iodine for lysine. Chlorine, bromine and iodine had the lowest propensity of interactions for cysteine, while fluorine had a lowest propensity for proline. These trends for highest propensity shifted towards the hydrophobic residues for all the halogens when only interactions with the side chain were considered. Halogens had equal propensities of interaction for the halogen bonding partners (nitrogen and oxygen atoms), albeit with different geometries. The optimal angle for interactions with halogens was ∼120° for oxygen atoms, and ∼96° for nitrogen atoms. The distance distributions of halogens with various amino acids were mostly bimodal, and the angle distributions were unimodal. Insights gained from this study have implications for the rational design of safer drugs and commercially important chemicals.

Desvenlafaxine succinate for major depressive disorder

Desvenlafaxine (O-desmethylvenlafaxine) is the major active metabolite of venlafaxine. Desvenlafaxine succinate is now undergoing active evaluation for its therapeutic efficacy in a variety of disorders, including major depressive disorder, vasomotor symptoms associated with menopause, fibromyalgia and diabetic neuropathy. Desvenlafaxine is a serotonin and norepinephrine reuptake inhibitor (SNRI) with similar activity to its parent compound venlafaxine, and little affinity for other brain targets, including muscarinic, cholinergic, histamine H(1) and alpha-adrenergic receptors. Desvenlafaxine has linear pharmacokinetics, low protein binding, a half-life of approximately 10 hours and is metabolized primarily via glucuronidation, and to a minor extent through CYP3A4. The desvenlafaxine succinate formulation appears to have good oral bioavailability. Clearance rates are reduced in the elderly, those with severe renal dysfunction and those with moderate to severe hepatic dysfunction, which may require dosage adjustments. Three published clinical trials have shown supportive but mixed results for the efficacy of desvenlafaxine in the treatment of major depressive disorder with daily doses ranging from 100 mg to 400 mg. One published clinical trial has shown mixed results for the efficacy of desvenlafaxine in the treatment of vasomotor symptoms associated with menopause with daily doses ranging from 50 mg to 200 mg. In these four clinical trials, desvenlafaxine was associated with several mild adverse effects, with the most common effect being nausea. Less common, but more serious, adverse effects reported in these trials included hypertension, QTc interval prolongation, exacerbation of ischemic cardiac disease, elevated lipids and elevated liver enzymes. The exact nature of these serious adverse effects, including the prevalence, clinical significance and potential risk factors, still needs to be fully elucidated. Desvenlafaxine has a low propensity for pharmacokinetic-based drug interactions, although it has the same potential for pharmacodynamic interactions as other serotonin-norepinephrine reuptake inhibitors. Desvenlafaxine is currently another treatment option for major depressive disorder. The only identified potential advantage of desvenlafaxine over venlafaxine or other antidepressant agents at this time is the apparently reduced risk for pharmacokinetic drug interactions.

Residue contact-count potentials are as effective as residue-residue contact-type potentials for ranking protein decoys

BackgroundFor over 30 years potentials of mean force have been used to evaluate the relative energy of protein structures. The most commonly used potentials define the energy of residue-residue interactions and are derived from the empirical analysis of the known protein structures. However, single-body residue 'environment' potentials, although widely used in protein structure analysis, have not been rigorously compared to these classical two-body residue-residue interaction potentials. Here we do not try to combine the two different types of residue interaction potential, but rather to assess their independent contribution to scoring protein structures.ResultsA data set of nearly three thousand monomers was used to compare pairwise residue-residue 'contact-type' propensities to single-body residue 'contact-count' propensities. Using a large and standard set of protein decoys we performed an in-depth comparison of these two types of residue interaction propensities. The scores derived from the contact-type and contact-count propensities were assessed using two different performance metrics and were compared using 90 different definitions of residue-residue contact. Our findings show that both types of score perform equally well on the task of discriminating between near-native protein decoys. However, in a statistical sense, the contact-count based scores were found to carry more information than the contact-type based scores.ConclusionOur analysis has shown that the performance of either type of score is very similar on a range of different decoys. This similarity suggests a common underlying biophysical principle for both types of residue interaction propensity. However, several features of the contact-count based propensity suggests that it should be used in preference to the contact-type based propensity. Specifically, it has been shown that contact-counts can be predicted from sequence information alone. In addition, the use of a single-body term allows for efficient alignment strategies using dynamic programming, which is useful for fold recognition, for example. These facts, combined with the relative simplicity of the contact-count propensity, suggests that contact-counts should be studied in more detail in the future.

Re‐examining the core features of autism: a comparison of autism spectrum disorder and fetal alcohol spectrum disorder

Autism spectrum disorder (ASD) and fetal alcohol spectrum disorder (FASD) are both characterized by social difficulties, but overall clinical descriptions of the two disorders are different. Twenty-nine children with autism and 33 children with pervasive developmental disorder-not otherwise specified (PDD-NOS) were compared to 29 children with FASD of equivalent age and full-scale IQ. To isolate social deficits that are most unique to ASD, all participants were administered the Autism Diagnostic Observation Schedule (ADOS). Parents of the children completed the Autism Diagnostic Interview-Revised (ADI-R). Difficulties in initiating social interaction, sharing affect, and using nonverbal communication were common in children with ASD but rare in children with FASD. Socially inappropriate behaviors and difficulty with peers were common in both groups. These findings suggest that whereas propensity for social interaction appears to be a differentiating factor between children with ASD and those with non-spectrum disorders, impaired quality of social interaction may be less diagnostically discriminative.

The Length Dependence of the PolyQ-mediated Protein Aggregation

Polyglutamine (polyQ) repeat disorders are caused by the expansion of CAG tracts in certain genes, resulting in transcription of proteins with abnormally long polyQ inserts. When these inserts expand beyond 35-45 glutamines, affected proteins form toxic aggregates, leading to neuron death. Chymotrypsin inhibitor 2 (CI2) with an inserted glutamine repeat has previously been used to model polyQ-mediated aggregation in vitro. However, polyQ insertion lengths in these studies have been kept below the pathogenic threshold. We perform molecular dynamics simulations to study monomer folding dynamics and dimer formation in CI2-polyQ chimeras with insertion lengths of up to 80 glutamines. Our model recapitulates the experimental results of previous studies of chimeric CI2 proteins, showing high folding cooperativity of monomers as well as protein association via domain swapping. Surprisingly, for chimeras with insertion lengths above the pathogenic threshold, monomer folding cooperativity decreases and the dominant mode for dimer formation becomes interglutamine hydrogen bonding. These results support a mechanism for pathogenic polyQ-mediated aggregation, in which expanded polyQ tracts destabilize affected proteins and promote the formation of partially unfolded intermediates. These unfolded intermediates form aggregates through associations by interglutamine interactions.

What type of faculty member interacts with what type of firm? Some reasons for the delocalisation of university–industry interaction

While there is significant interest in improving university–industry interaction, literature on the university side has tended not to focus on the characteristics of the personnel involved and has largely ignored the issue that there are differences between types of faculty member in their degrees of interaction. This question is especially relevant at regional level, as those faculty members who do interact with industry may show a preference for firms that are larger and technologically superior to those in the region. Most analysts, however, have tended to focus on the national level, particularly on those countries at the forefront of technological innovation. In the absence of any formal theory, we propose a two-step method to formulate the hypothesis that only selected faculty members interact with selected firms. First, we identify the type of faculty member who interacts with firms. Second, we examine whether this type of faculty member interacts with every type of firm. A test sample is drawn from the Valencian Community of Spain, a region with low absorptive capacity, where firms may show undesirable properties for university interaction. The results allow us to challenge the view that certain individual universities may show a higher propensity for interaction once we take into account differences between the individual characteristics of their faculty members. We also claim that in a region like the Valencian Community, faculty members who usually participate in contracts (male, holding an administrative position) do so mainly with larger firms, but not with firms from their own region, where they find lower technological standards. This partly explains the delocalisation of university–industry interaction.

Feeling emotional: the amygdala links emotional perception and experience

Feeling emotional: the amygdala links emotional perception and experience

Oxcarbazepine in the treatment of bipolar and schizoaffective disorders

Oxcarbazepine is an antiepileptic drug that has been approved by the US FDA and is indicated for use as monotherapy or adjunctive therapy in the treatment of partial seizures in adults and children aged over 4 years. The aim of this report is to investigate the results of clinical trials in order to ascertain the efficacy and safety of oxcarbazepine for use in bipolar disorder and schizoaffective disorder. Oxcarbazepine is a keto-congener of carbamazepine with fewer side effects and drug interactions. Orally administrated oxcarbazepine is rapidly and completely absorbed and has a half-life of 9 h. Currently, there is a lack of controlled clinical trials studying the use of oxcarbazepine. In light of controlled and open-label prospective studies, it may be useful for manic symptoms in the treatment of bipolar and schizoaffective patients. Case reports, retrospective and prospective studies suggest that oxcarbazepine might have prophylactic efficacy and long-term benefit for these patients. In addition, owing to its lower propensity for drug interactions and side effects, it may be useful in the treatment of refractory patients with bipolar and schizoaffective disorder. However, most of the trials have relevant methodological shortcomings. The side-effect profile of oxcarbazepine is similar to carbamazepine, but the severity of these effects appears to be slightly less. The symptoms that are most frequently associated with the use of oxcarbazepine are asthenia, headache, dizziness, somnolence, nausea, diplopia and skin rash. Isolated cases of hyponatremic coma have been reported, thus electrolyte abnormalities should be closely monitored. Oxcarbazepine is now a generic drug, but the metabolite licarbazepine and other related compounds, such as eslicarbazepine, are currently being studied under controlled conditions and might become useful therapies for bipolar and schizoaffective disorder in the future.

Maximizing anticholinergic therapy for overactive bladder: has the ceiling been reached?

Urinary incontinence affects an estimated 20-33% of adults the USA and 55% of the country's elderly [1], having a more substantial impact on the physical and mental dimension of quality of life than other common chronic diseases. Muscarinic receptor antagonists, including oxybutynin, tolterodine, trospium chloride, darifenacin, and solifenacin, are front-line therapies for overactive bladder (OAB), with an efficacy of 65-75% in reducing major symptoms. Strategies to increase the therapeutic index have included behavioural therapy, flexible dosing, and dose escalation, as well as newer formulations that reduce anticholinergic side-effects. Among approved OAB agents, the oxybutynin transdermal-delivery system has been associated with a lower incidence of dry mouth than immediate- and extended-release formulations of traditional agents. With a low propensity for drug interactions and dry mouth, it is a likely candidate for older patients taking multiple medications. The transdermal patch bypasses systemic and first-pass metabolism, avoiding higher plasma concentrations of the active metabolite (N-desethyloxybutynin) thought to be associated with dry mouth symptoms. Anticholinergics have a significant role to play in the management of OAB; newer drugs targeted toward muscarinic receptors, and novel delivery systems, continue to increase the therapeutic index for this condition.