Patient reporting of potential adverse drug reactions: a methodological study.

AIMS: To develop a systematic generic method of enabling patients to report symptoms which they believe to be due to a particular prescribed drug. METHODS: A piloted body system-based questionnaire was distributed to patients registered with 79 medical practices in Grampian prescribed one of nine recently marketed 'black triangle' drugs. These comprised four antidepressants, three antiepileptics and two analgesics. This requested respondents to identify any symptoms experienced over the previous year which they thought could be due to the 'black triangle' drug they had used. A sample of medical records was examined to compare symptoms recorded with those reported by patients. A classification system was developed for the study to enable the assessment of symptoms reported for their potential relationship to patients' drug therapy. All symptoms reported were classified, taking into account information provided by patients on their concomitant drugs and diseases. A specialist pharmacist independently re-classified a sample of the symptoms to validate the process. RESULTS: A 36.3% response rate was obtained (837/2307) with 742 respondents (88.6%) reporting at least one symptom. The median per patient was 6.0 (range 0--71), with almost half (406, 48.5%) reporting fewer than five symptoms. Most symptoms (71.0%) were classified as being probably or possibly related to the drugs studied. Agreement between researcher and specialist on the classification of 75.3% of 716 symptoms was obtained (Kappa=0.563). Responses from patients prescribed antidepressant drugs were more likely to include symptoms potentially caused by these drugs (74.5% of all symptoms reported) than those from patients prescribed analgesics (67.4%) or antiepileptics (65.1%, chi2 = 23.858, d.f. = 2, P < 0.001). Patients reporting large numbers of symptoms were more likely to report some which were classed as unlikely to be an ADR or unattributable (chi2 = 80.587, d.f. = 3, P < 0.001). Of the 742 reporting symptoms in questionnaires, 402 (54.2%) claimed to have reported some or all of these to their doctor. Only 162 (22.6%) of 716 patient-reported symptoms were documented in the primary care medical records of 103 patients prescribed tramadol or venlafaxine. CONCLUSIONS: Respondents were clearly willing to report symptoms, the majority of which were classed as possibly/probably related to the drugs studied. The results suggest that patients do not report all symptoms they suspect to be ADRs to their GP and that GPs do not record all symptoms which may be reported to them. The method could help to identify problems which patients perceive as being related to their drug therapy and contribute to increased ADR reporting.

Vancomycin resistance reversal in enterococci by flavonoids.

The development of clinical vancomycin-resistant strains of enterococci (VRE) is a major cause for concern. Here we show that a combination of galangin or 3,7-dihydroxyflavone with vancomycin may be used to sensitize resistant strains of Enterococcus faecalis and Enterococcus faecium to the level of vancomycin-sensitive strains. Minimum inhibitory concentrations (MICs) and viable counts were determined in Iso-sensitest broth using a microtitre method. MICs of vancomycin against 67% of resistant clinical isolates and a type strain of enterococci were lowered from > 250 microg mL(-1) to < 4 microg mL(-1) in the presence of galangin (12.5 microg mL(-1)) or 3,7-dihydroxyflavone (6.25 microg mL(-1)). Viable counts for type culture E. faecalis ATCC 51299 showed the flavonoids alone significantly lowered numbers of colony forming units (CFUs). CFUs were maintained at low levels (< 10(3) CFU mL(-1)) for 24 h by vancomycin/flavone combinations. This combinational action in reversing vancomycin resistance of enterococci highlights novel drug targets and has importance in the design of new therapeutic regimes against resistant pathogens.

Baicalin synergy with beta-lactam antibiotics against methicillin-resistant Staphylococcus aureus and other beta-lactam-resistant strains of S. aureus.

Bacterial resistance to antibiotics is a serious global problem and includes strains of beta-lactam-resistant Staphylococcus aureus and methicillin-resistant S. aureus (MRSA). Novel antimicrobials and/or new approaches to combat the problem are urgently needed. The Chinese herb Xi-nan Huangqin (Scutellaria amoena C.H. Wright) has been used in traditional Chinese medicine to treat a wide range of infectious diseases. In this study we have examined the antibacterial action of baicalin, a flavone isolated from the herb. When combined with 16 microg mL(-1) baicalin, minimum inhibitory concentrations (MICs) of benzylpenicillin against MRSA and penicillin-resistant S. aureus were reduced from 125 and 250 microg mL(-1) to 4 and 16 microg mL(-1), respectively. This activity of baicalin was dose-dependent. Viable counts showed that the killing of MRSA and beta-lactam-resistant S. aureus cells by 10 to 50 microg mL(-1) ampicillin, amoxycillin, benzylpenicillin, methicillin and cefotaxime was potentiated by 25 microg mL(-1) baicalin. From the study it was concluded that baicalin has the potential to restore the effectiveness of beta-lactam antibiotics against MRSA and other strains of beta-lactam-resistant S. aureus. In view of its limited toxicity baicalin offers potential for the development of a valuable adjunct to beta-lactam treatments against otherwise resistant strains of microorganisms.

Intermediate species possessing bent DNA are present along the pathway to formation of a final TBP-TATA complex.

Binding of the TATA-binding protein (TBP) to the "TATA" sequences present in the promoters of eukaryotic class II genes is the first step in the sequential assembly of transcription pre-initiation complexes. Myriad structural changes, including severe bending of the DNA, accompany TBP-TATA complex formation. A detailed kinetic study has been conducted to elucidate the mechanistic details of TBP binding and DNA bending. The binding of Saccharomyces cerevisiae TBP to the adenovirus major late promoter (AdMLP) was followed in real-time through a range of temperatures and TBP concentrations using fluorescence resonance energy transfer (FRET) and stopped-flow mixing. The results of association and relaxation kinetics and equilibrium binding experiments were analyzed globally to obtain the complete kinetic and energetic profile of the reaction. This analysis reveals a complex mechanism with two intermediate species, with the DNA in the intermediates apparently bent similarly to the DNA in the final complex. TBP binding and DNA bending occur simultaneously through the multiple steps of the reaction. The first and third steps in this sequential process show nearly identical large increases in both enthalpy and entropy, whereas the middle step is highly exothermic and proceeds with a large decrease in entropy. The first intermediate is significantly populated at equilibrium and resembles the final complex both structurally and energetically. It is postulated that both this intermediate and the final complex bind transcription factor IIB in the second step of pol II pre-initiation complex assembly. A consequence of such a reactive intermediate is that the rate of assembly of transcriptionally competent pre-initiation complexes from bi-directionally bound TBP is greatly increased.

In-vitro investigation of the antibacterial activity of agents which may be used for the oral treatment of lung infections in CF patients.

The effect of triple therapy with ciprofloxacin, trimethoprim and either sulphadiazine or sulphamethoxazole on the MICs and development of resistance of three strains of Pseudomonas aeruginosa, two strains of Staphylococcus aureus and one of Burkholderia cepacia was compared with that of single or dual therapy with these agents using an agar dilution method. Ciprofloxacin MICs were 0.2-0.8 mg/L for the P. aeruginosa and S. aureus strains. For trimethoprim the MIC ranges were 64-128 and 0.25-1 mg/L for P. aeruginosa and S. aureus, respectively. For the sulphonamides the ranges were 64-2500 and 20-39 mg/L for P. aeruginosa and S. aureus, respectively. All combinations of agents were effective at lower concentrations than the single agents. The combination of ciprofloxacin, sulphonamide and trimethoprim showed enhanced activity against all test organisms. The highest ciprofloxacin concentration was one-tenth of the normally attainable serum concentration of 2.5 mg/L. Thus peak plasma concentrations of > or =8 x MIC for ciprofloxacin against P. aeruginosa and S. aureus are theoretically achievable in the presence of clinically acceptable concentrations of trimethoprim and a sulphonamide, making the development of resistance less likely. The development of resistance, as shown by the proportional increase in MICs, was repressed by the triple regimen as compared with the development of resistance to agents used singly or in pairs. Killing curve determinations also demonstrated the advantage of the triple-agent therapy against all organisms tested: the combination of ciprofloxacin 0.5 mg/L, trimethoprim 1 mg/L and sulphadiazine 20 mg/L had an initial bactericidal effect against log-phase inocula of 10(6) cfu/mL of two clinical strains of P. aeruginosa and one clinical strain of S. aureus. The pseudomonas strains were reduced by 2-4 log cycles. Both recovered over 24 h but did not exceed the initial inoculum. The S. aureus was reduced to 10(2) cfu/mL in 4 h and did not recover over 24 h. A repeat dose of the triple therapy against the more resistant of the P. aeruginosa strains after 12 h also had a bactericidal effect. These data suggest the possibility of an effective exclusively oral therapy for the treatment of lung infections in cystic fibrosis patients.

Drug-related problems in elderly patients admitted to Tayside hospitals, methods for prevention and subsequent reassessment.

INTRODUCTION: although drug-related problems (DRPs) are known to be prevalent in elderly patients, the literature on prevention of iatrogenic disease is sparse. The present study addresses this requirement. OBJECTIVES: to assess the incidence of DRPs in elderly patients admitted to Tayside hospitals before (phase I) and after (phase II) implementation of preventive strategies. DESIGN: all elderly people admitted to hospital were screened by a pharmacist; individual case reviews were prepared for all those with a potential DRP and reviewed by a three-member panel which made a final decision on the presence of a DRP and its contribution to admission. SETTING: all hospital wards admitting elderly patients in the Tayside region of Scotland. SUBJECTS: 1011 elderly patient admissions over a 9-month period (phase I); 857 elderly patient admissions over an 8-month period (phase II). MAIN OUTCOME MEASURES: incidence of DRPs before and after targeted intervention strategies (information bulletin for general practitioners, patient information leaflet, oral presentation to trainee general practitioners). RESULTS: in phase I, the incidence of DRPs was 144/1011 (14.2%), with 54/1011 (5.3%) of the admissions identified as being definitely or probably drug-related. Non-steroidal anti-inflammatory drugs (NSAIDs) were the main drug group involved, being responsible for 15/54 (28%) of admissions primarily due to a DRP. Over 66% of admissions due to adverse effects of NSAIDs were considered to be definitely preventable. In phase II, after targeted intervention strategies, there was no significant reduction in total incidence of DRPs or incidence of DRPs related to NSAIDs. However, there appeared to be an improvement in the first 4 months, and a significant drop in NSAID prescribing in Tayside compared with the rest of Scotland was observed. CONCLUSION: DRPs remain a significant problem in elderly patients and NSAIDs are the major contributor. The intervention strategies used in the study were not demonstrably effective, but a continuous programme of education may be necessary to limit NSAID use.

Sensitive high-performance liquid chromatographic assay for aminoglycosides in biological matrices enables the direct estimation of bacterial drug uptake.

Following the development of a sensitive high-performance liquid chromatographic (HPLC) assay for gentamicin in biological matrices, the utility of this assay for the determination of other clinically important aminoglycosides (neomycin, netilmicin and sisomicin) in bacterial culture media or plasma is demonstrated. The high sensitivity of the assay enables direct measurement of the aminoglycoside content of bacterial cells cultured in the presence of unlabelled drug.

Is the ultrastructural damage caused by subinhibitory concentrations of trimethoprim and sulphadiazine part of their normal mechanism of action?

The test organism was Escherichia coli 1810 which was highly resistant to trimethoprim (TMP). Electron microscopy (EM) of cells grown in the presence of subinhibitory concentrations of 300 micrograms/ml sulphadiazine (SD) and/or 300 micrograms/ml TMP indicated marked structural damage. No effect on the outer membrane (OM) or ultrastructure of E. coli 1810 was observed with 7.68 micrograms/ml TMP and/or 16.9 micrograms/ml SD. Concentrations of antibacterials affecting the ultrastructure of the bacterial cells of resistant and sensitive E. coli as determined by EM, were shown by a permeability probe (Triton X-100) to alter the OM permeability and to partially inhibit growth of E. coli 1810 cultures. It was concluded that, since the action of SD and TMP, singly and in combination, on the cell structure of E. coli 1810 took place only at concentrations approaching the respective MICs, then this was a part of their normal mechanisms of antibacterial action.

Detection of stroke during cardiac operations with somatosensory evoked responses.

OBJECTIVES: The objectives of this study were to determine if monitoring of intraoperative somatosensory evoked potentials could be used to detect stroke during cardiac operations and to establish indicators of cerebral ischemia based on changes in these potentials. METHODS: Twenty-five patients undergoing cardiac operations underwent preoperative and postoperative neurologic examinations as well as intraoperative recording of somatosensory evoked potentials. Detailed analysis of the waveforms of these potentials was performed. RESULTS: Two of the 25 patients had intraoperative strokes. These patients and only these patients had changes in their somatosensory evoked potentials during the operation suggesting cerebral ischemia. The unilateral disappearance of the cortical somatosensory evoked potential waves correlated significantly with the clinical outcome of stroke (p < 0.004). Ischemic changes were detected in real time and were related to the removal of the aortic crossclamp in one patient and to the initiation of cardiopulmonary bypass in the other. CONCLUSIONS: Somatosensory evoked potentials can detect intraoperative stroke during cardiac operations. Acute, unilateral decreases in amplitude of the cortical potential are more useful than changes in latency in detecting intraoperative stroke.

Mechanism for synergism between sulphonamides and trimethoprim clarified.

Pseudomonas aeruginosa, Escherichia coli, Pseudomonas cepacia and Moraxella catarrhalis were selected for their markedly different resistance patterns to sulphonamides and trimethoprim. In addition, strains of E. coli and P. cepacia were selected having different resistance profiles to the inhibition of dihydropteroate synthetase and dihydrofolate reductase. All inhibitors of dihydropteroate synthetase combined in any combination with inhibitors of dihydrofolate reductase resulted in mutual enhancement of bacterial uptakes of the inhibitors and corresponding increased antibacterial activity of the combinations. High concentrations of sulphonamides or p-aminobenzoic acid plus trimethoprim caused a decrease in overall activity of the combination and indicated that both sulphonamides and p-aminobenzoic acid at high concentrations can interact with dihydrofolate reductase. The antibacterial activity of p-aminobenzoic acid at high concentrations is considered to be a blocking effect on dihydrofolate reductase even though p-aminobenzoic acid at low concentrations is an essential part of the synthesis of dihydrofolic acid. These findings support an alternative hypothesis for the mechanism of antibacterial action of individual antifolates and their mechanism of synergism in combination.

Excipient interaction with cetylpyridinium chloride activity in tablet based lozenges.

PURPOSE: The purpose of the investigation was to determine the effect of tablet excipients on the activity of cetylpyridinium chloride (CPC) and the relative interaction between excipients and CPC. METHODS: An analytical assay was developed to evaluate the interaction between CPC and the excipients. In vivo activity was investigated using six volunteers by determining the reduction in colony forming units recoverable from the oropharynx after sucking each proprietary lozenge separately on different days. In vitro determinations investigated the relative antimicrobial activity of aqueous solutions of the lozenges and, the effect of pH and tablet base excipients on that activity against Staphylococcus aureus, Streptococcus pyogenes and Candida albicans. RESULTS: Both in vivo and in vitro results showed that the tablet based lozenges had markedly reduced antimicrobial activities compared with previous results with a candy based lozenge (in vivo and in vitro) or the same concentration of aqueous CPC (in vitro). Magnesium stearate suspensions in CPC 250 micrograms/ml indicated that magnesium stearate adsorbed CPC and at 0.4% lozenge weight and above significantly reduced the antimicrobial activity of CPC 250 micrograms/ml. CONCLUSIONS: The reduced activity of CPC in tablet based lozenges resulted from a decreased availability of CPC in solution due to an adsorption of CPC on magnesium stearate. To avoid this reduction in activity tablet based lozenges containing CPC 250 micrograms/ml, or similar concentrations, plus magnesium stearate should contain not more than 0.3% w/w lozenge weight of the lubricant.

Determination of peptidoglycan-associated protein in Escherichia coli NCIB 8545 by capillary zone electrophoresis.

An efficient reliable and sensitive capillary zone electrophoresis assay for the six major bacterial peptidoglycan-associated proteins of Escherichia coli NCIB 8545 is described. The method provides the facility to determine quantitatively the effect of antibacterials on bacterial peptidoglycan-associated protein synthesis and thus to further elucidate the mechanism of antibacterial action of such drugs as the antifolates which recently have been shown to adversely affect peptidoglycan synthesis.

Brodimoprim synergy against Enterococcus faecalis evaluated in vitro.

Combinations of either brodimoprim or trimethoprim plus either carbenicillin, gentamicin, ciprofloxacin or rifampicin showed synergy at sub-inhibitory concentrations against both Enterococcus faecalis NCTC 5957 and 775. Brodimoprim alone and in combination showed greater antibacterial activity against both strains of E. faecalis than trimethoprim. MBCs of brodimoprim and trimethoprim were 14.4 and 25.6 mg/L for E. faecalis NCTC 5957 and 7.2 and 12.8 mg/L for E. faecalis NCTC 775. Combinations of either brodimoprim or trimethoprim plus the other antibacterial agents, except gentamicin and dibromopropamidine isethionate, were bactericidal at achievable plasma concentrations. Viable count determinations of cultures of both test organisms in the presence of 3/4 of the MIC of each of the four antibiotics and the two antifolates alone and combinations of each antibiotic with either brodimoprim or trimethoprim indicated that only the combinations prevented recovery and regrowth of the cultures over 24 h. The ATP released from cultures of both strains of E. faecalis treated with brodimoprim and trimethoprim at the same concentrations was approximately 1.5 times greater with brodimoprim than with trimethoprim. Combinations of 3/4 of the MIC of each of the antibiotics in combination with 3/4 of the MIC of brodimoprim against cultures of both strains of E. faecalis resulted in greater release of ATP than occurred with equivalent trimethoprim combinations. It is postulated that the increased activities observed with the brodimoprim combinations resulted from an effect of brodimoprim on the bacterial cell permeability control. These results indicate that both brodimoprim and trimethoprim offer potential benefits for use with either carbenicillin, gentamicin, ciprofloxacin or rifampicin for the treatment of E. faecalis infections.

The effect of formulation on the antimicrobial activity of cetylpyridinium chloride in candy based lozenges.

PURPOSE: The purpose of this investigation was to determine the influence on the antimicrobial activity of cetylpyridinium chloride of the various components of the formulation of each of six candy based lozenges. METHODS: In vivo activity was investigated using six volunteers by determining the reduction in colony forming units recoverable from the oropharynx after sucking each lozenge separately on different days. In vitro determinations investigated the relative activity of aqueous solutions of the lozenges, the effect on activity of additional active ingredients, pH and lozenge base ingredients against separate inocula of each of the test organisms Staphylococcus aureus, Streptococcus pyogenes and Candida albicans. RESULTS: Both in vivo and in vitro results showed that the pH of the dissolved lozenge solution was the single most influential readily adjustable formulation parameter which significantly influenced the activity of cetylpyridinium chloride activity in candy based lozenges. CONCLUSIONS: Lozenges containing cetylpyridinium chloride as the active ingredient should be formulated at a pH greater than 5.5.

Sensitive fluorimetric determination of gentamicin sulfate in biological matrices using solid-phase extraction, pre-column derivatization with 9-fluorenylmethyl chloroformate and reversed-phase high-performance liquid chromatography.

A high-performance liquid chromatographic method is described for the determination of gentamicin in bacterial culture medium or plasma with increased sensitivity and improved separation of the C1 component. Gentamicin was extracted from the biological matrix with high efficiency using carboxypropyl (CBA)-bonded silica. Derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl) followed by C18 reversed-phase chromatography allowed the fluorimetric detection of gentamicins C1, C1a and C2. A fourth component, considered to be gentamicin C2a, was partially resolved from the C2 peak. Optimal conditions for the extraction and derivatization of gentamicin are described. The detection limit was below 50 micrograms/l, the assay was linear to 5 mg/l and showed good reproducibility. It is concluded that pre-column derivatization with FMOC-Cl substantially improves the analysis of gentamicin compared with present methods based on reaction with o-phthaldialdehyde.

Mechanism of sulphadiazine enhancement of trimethoprim activity against sulphadiazine-resistant Enterococcus faecalis.

Sulphadiazine had little or no antibacterial effect against three strains of Enterococcus faecalis (MICs of above 3600 mg/L) but it caused approximately six-fold increases in bacterial uptake of trimethoprim, increased release of bacterial ATP and produced ultrastructural damage to both the trimethoprim resistant E. faecalis 463 and the trimethoprim sensitive NCTC 5957. MICs of trimethoprim were 0.6, 0.8 and 76.8 mg/L for E. faecalis NCTC 775, NCTC 5957 and 463 respectively. When log phase E. faecalis 463 and NCTC 5957 were grown for 4 h in trimethoprim 56 and 0.6 mg/L plus sulphadiazine 320 and 100 mg/L respectively there was an approximate ten-fold and nine-fold increase in uptake of sulphadiazine and a two-fold increase in leakage of ATP. Trimethoprim caused more damage to the cell wall and cytoplasmic membrane than sulphadiazine but the combination of sulphadiazine plus trimethoprim caused the most cell damage. The increased activity observed with the combination seems very likely to have resulted from the increased uptakes of the antibacterials, which in turn had resulted from the cell wall damage and consequent increased cell permeability caused by each antibacterial. It is proposed that a markedly subinhibitory concentration of sulphadiazine enhanced the antibacterial activity of trimethoprim against all three strains of E. faecalis by this mechanism.

Activity of p-aminobenzoic acid compared with other organic acids against selected bacteria.

The antibacterial activity of p-aminobenzoic acid against Listeria monocytogenes, Salmonella enteritidis and Escherichia coli was compared with the activity of commonly used acidulants: formic, propionic, acetic, lactic and citric acids. Viable count evaluations and MIC determinations indicated that p-aminobenzoic acid caused greater inhibitory effects than the other organic acids. The activity of p-aminobenzoic acid on the growth of the test organisms at selected pH values indicated that p-aminobenzoic acid was more active at low pH than at high pH. Uptake studies showed that the uptake of p-aminobenzoic acid by E. coli was markedly decreased as the pH values increased. Electron micrographs of E. coli cells grown in the presence of p-aminobenzoic acid indicate that p-aminobenzoic acid caused marked damage to the cell envelope. It is suggested that p-aminobenzoic acid has at least two mechanisms of action: one mechanism in common with other organic acids and the other mechanism by interfering with the synthesis of the peptidoglycan layer by an action on the dihydrofolate reductase enzyme.

Determination of thymidine, uracil and p-aminobenzoic acid in bacteriological cultures by capillary zone electrophoresis.

A capillary zone electrophoresis assay has been developed which simultaneously separates and quantifies the bacterial metabolites thymidine, uracil and p-aminobenzoic acid present at bacteriologically relevant concentrations in a supplemented minimal bacteriological medium. Sulphadiazine was used as the internal standard.