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At least 19 recordsLinked to original sources

Drug discrimination procedures: differential characteristics of the drug A vs drug B and the drug A vs drug B vs no drug cases.

Two groups of pigeons with a history of two choice operant drug discrimination tasks (3.0 mg/kg morphine versus 5.6 mg/kg cocaine, and 3.0 mg/kg morphine versus 3.0 mg/kg cocaine, respectively; Swedberg and Järbe 1985) were subjected to three choice tasks in which responses on a third manipulandum were reinforced in the no drug condition. Training drugs generalization gradients in both groups were similar to those normally obtained in two choice drug versus no drug tasks. The salience differences between the training stimuli within the groups observed in the previous two choice task did not differentially affect the three choice discrimination gradients. Tests with novel drugs after the introduction of the no drug condition yielded increased responding to the no drug condition with the exception of the dopamine agonist apomorphine. Results are discussed in terms of a discrimination learning model specifying principles of relative discriminative stimulus control in various discrimination cases.

Animals↗

Herb-drug, food-drug, nutrient-drug, and drug-drug interactions: mechanisms involved and their medical implications.

Adverse drug reactions (ADRs) and iatrogenic diseases have been identified as significant factors responsible for patient morbidity and mortality. Significant studies on drug metabolism in humans have been published during the last few years, offering a deeper comprehension of the mechanisms underlying adverse drug reactions and interactions. More understanding of these mechanisms, and of recent advances in laboratory technology, can help to evaluate potential drug interactions when drugs are prescribed concurrently. Increasing knowledge of interindividual variation in drug breakdown capacity and recent findings concerning the influence of environment, diet, nutrients, and herbal products can be used to reduce ADRs and iatrogenic diseases. Reviewed data suggest that drug treatment should be increasingly custom tailored to suit the individual patient and that appropriately co-prescribed diet and herbal remedies, could increase drug efficacy and lessen drug toxicity. This review focuses mainly on recently published research material. The cytochrome p450 enzymes, their role in metabolism, and their mechanisms of action are reviewed, and their role in drug-drug interactions are discussed. Drug-food and drug-herb interactions have garnered attention. Interdisciplinary communication among medical herbalists, medical doctors, and dietetic experts needs to be improved and encouraged. Internet resources for obtaining current information regarding drug-drug, drug-herb, and drug-nutrient interactions are provided.

Adverse Drug Reaction Reporting Systems↗

Continuous five-drug versus alternating three-drug and two-drug chemotherapy after five-drug or three-drug induction in extensive small cell lung cancer.

Fifty-six patients with extensive small cell lung cancer were treated with vincristine, doxorubicin, cisplatin, etoposide, and cyclophosphamide in a prospective randomized trial using all five drugs together or as three-drug (cisplatin, etoposide, cyclophosphamide) and two-drug (doxorubicin, vincristine) combinations given sequentially, then alternatively. The five-drug combination was associated with a higher overall regression rate (p = 0.03), higher complete regression rate (p = 0.09), prolonged time to first progression (p = 0.03), more nervous system initial failures (p = 0.07), more anemia requiring transfusion (p = 0.04), but no prolongation of overall survival (median 332 days for five-drug, median 303 days for three-drug and two-drug). Until more and better chemotherapeutic agents become available, little or no advantage is likely to be gained for patients with small cell lung cancer given sequential, or alternating chemotherapy.

Adult↗

Short-term low-dose corticosteroids vs placebo and nonsteroidal antiinflammatory drugs in rheumatoid arthritis.

BACKGROUND: The effect of low dose corticosteroids, equivalent to 15 mg prednisolone daily or less, in patients with rheumatoid arthritis has been questioned. We therefore performed a systematic review of trials which compared corticosteroids with placebo or non-steroidal, anti-inflammatory drugs. OBJECTIVES: To determine whether short-term (i.e. as recorded within the first month of therapy), oral low-dose corticosteroids (corresponding to a maximum of 15 mg prednisolone daily) is superior to placebo and nonsteroidal, antiinflammatory drugs in patients with rheumatoid arthritis. SEARCH STRATEGY: Medline Silverplatter, The Cochrane Controlled Trials Register, reference lists and a personal archive. SELECTION CRITERIA: All randomised studies comparing an oral corticosteroid (not exceeding an equivalent of 15 mg prednisolone daily) with placebo or a nonsteroidal, antiinflammatory drug were eligible if they reported clinical outcomes within one month after start of therapy. DATA COLLECTION AND ANALYSIS: Decisions on which trials to include were made independently by two observers based on the methods sections of the trials only. Standardised effect measures were used for the statistical analyses; the random effects model was used if P<0.10 for the test of heterogeneity. MAIN RESULTS: Ten studies, involving 320 patients, were included in the meta-analysis. Prednisolone had a marked effect over placebo on joint tenderness (standardised effect size 1.31, 95% confidence interval 0.78 to 1.83), pain (standardised effect size 1.75, 0.87 to 2.64) and grip strength (standardised effect size 0.41, 0.13 to 0.69). Measured in the original units, the differences were 12 tender joints (6 to 18) and 22 mm Hg (5 to 40) for grip strength. Prednisolone also had a greater effect than nonsteroidal, antiinflammatory drugs on joint tenderness (standardised effect size 0.63, 0.11 to 1.16) and pain (standardised effect size 1.25, 0.26 to 2.24), whereas the difference in grip strength was not significant (standardised effect size 0.31, -0.02 to 0.64). Measured in the original units, the differences were 9 tender joints (5 to 12) and 12 mm Hg (-6 to 31). The risk of adverse effects, also during moderate- and long-term use, seemed acceptable. REVIEWER'S CONCLUSIONS: Prednisolone in low doses (not exceeding 15 mg daily) may be used intermittently in patients with rheumatoid arthritis, particularly if the disease cannot be controlled by other means. Since prednisolone is highly effective, short-term placebo controlled trials studying the clinical effect of low-dose prednisolone or other oral corticosteroids are no longer necessary.

Anti-Inflammatory Agents, Non-Steroidal↗

Detecting drug-drug interactions using a database for spontaneous adverse drug reactions: an example with diuretics and non-steroidal anti-inflammatory drugs.

OBJECTIVE: Drug-drug interactions are relatively rarely reported to spontaneous reporting systems (SRSs) for adverse drug reactions. For this reason, the traditional approach for analysing SRS has major limitations for the detection of drug-drug interactions. We developed a method that may enable signalling of these possible interactions, which are often not explicitly reported, utilising reports of adverse drug reactions in data sets of SRS. As an example, the influence of concomitant use of diuretics and non-steroidal anti-inflammatory drugs (NSAIDs) on symptoms indicating a decreased efficacy of diuretics was examined using reports received by the Netherlands Pharmacovigilance Foundation Lareb. METHODS: Reports received between 1 January 1990 and 1 January 1999 of patients older than 50 years were included in the study. Cases were defined as reports with symptoms indicating a decreased efficacy of diuretics, non-cases as all other reports. Exposure categories were the use of NSAIDs or diuretics versus the use of neither of these drugs. The influence of the combined use of both drugs was examined using logistic regression analysis. RESULTS: The odds ratio of the statistical interaction term of the combined use of both drugs was increased [adjusted odds ratio 2.0, 95% confidence interval (CI) 1.1-3.7], which may indicate an enhanced effect of concomitant drug use. CONCLUSION: The findings illustrate that spontaneous reporting systems have a potential for signal detection and the analysis of possible drug-drug interactions. The method described may enable a more active approach in the detection of drug-drug interactions after marketing.

Adverse Drug Reaction Reporting Systems↗

Evaluation of drug interactions with P-glycoprotein in drug discovery: in vitro assessment of the potential for drug-drug interactions with P-glycoprotein.

The pharmacological effects of a drug are highly dependent on the absorption, metabolism, elimination, and distribution of the drug. In the past few years it has become apparent that transport proteins play a major role in regulating the distribution, elimination and metabolism of some drugs. As a consequence of our new understanding of the influence of transport proteins on the pharmacokinetic and pharmacodynamic behavior of drugs, increasing attention has been focused on the potential for drug-drug interactions arising from interactions with drug transport proteins. The efflux transporter P-glycoprotein (P-gp) has received the most attention with regard to its role in restricting drug absorption and distribution and as a potential source for variability in drug pharmacokinetics and pharmacodynamics. This review will focus on the evaluation of drug candidates to assess the potential for drug interactions at the level of P-gp. We will discuss the role of P-gp in drug disposition, the biochemistry of P-gp efflux as it relates to model systems to study drug interactions with P-gp, and the implementation of P-gp assay models within the drug discovery process.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Increased drug sensitivity in the drug discrimination procedure afforded by drug versus drug training.

Rats were trained to discriminate norfenfluramine (NF) 1.4 mg/kg from its vehicle or amphetamine (AMPH) 0.8 mg/kg or pentobarbital (PB) 6.0 mg/kg in order to determine the role that drug combination training plays in the rate of learning and sensitivity to lower drug doses. The results suggest that drug versus drug training can increase the rate of drug discrimination learning for some drugs that are learned slowly when trained in a drug versus vehicle training procedure, whereas drug versus drug training does not increase the rate of learning for other drugs that are learned rapidly. Drug versus drug training does, however, appear to increase the level of stimulus control of the training drug for all drugs examined in this study.

Amphetamine↗

A human drug metabolism database: potential roles in the quantitative predictions of drug metabolism and metabolism-related drug-drug interactions.

Previous attempts to predict drug metabolism and drug-drug interaction possibilities by deploying databases that house established drug metabolism results have been only marginally successful. Consideration of some of the key issues and concerns derived from these efforts suggests that three major hurdles loom in front of using xenobiotic metabolism databases more effectively in the future. These hurdles include: the need for an improved treatment of chemical structure in three-dimensions (3D); a better quantitative accounting of competitive and complementary biotransformation pathways; and, the critical need for a comprehensive, human drug metabolism database (hDMdb) that can serve as a bio/chemoinformatic resource pertaining to drug metabolism and drug metabolism-related drug-drug interactions in general. Approaches that might be taken to traverse each of these hurdles are discussed herein where: the first involves maturation of chemical structures from simple 2D entries into more sophisticated 3D displays that can also account for interactions with relevant biological surfaces; the second involves a systematic, pair-wise comparison of various metabolic options in a statistically driven manner relative to chemical structure descriptors; and, the third involves mounting a hDMdb on the Internet in a user-friendly manner that it is available via a non-profit format.

Databases, Factual↗

A novel skeletal drug delivery system using a self-setting calcium phosphate cement. 5. Drug release behavior from a heterogeneous drug-loaded cement containing an anticancer drug.

A novel drug delivery device based on a self-setting bioactive calcium phosphate cement formed from tetracalcium phosphate and dicalcium phosphate has been developed and tested in vitro using the anticancer agent 6-mercaptopurine (6-MP) as a model compound. X-ray diffraction results suggest that equimolar mixtures of the calcium phosphate salts were transformed into hydroxyapatite after being mixed with a dilute phosphoric acid solution, even in the presence of various amounts of 6-MP powder. The inclusion of 6-MP in the reaction mixture resulted in the formation of a homogeneous drug-containing cement. Alternatively, the drug was loaded after cement formation to produce a heterogeneous drug-containing pellet. In vitro drug release from both the homogeneous and heterogeneous drug-loaded cement pellets into simulated body fluid (pH 7.25, 37.0 degrees C) was measured using the rotating-disk method. Release from the homogeneous 5% drug-loaded cements did not obey the Higuchi equation. The release rate from the heterogeneous drug-loaded cements of different thicknesses (1, 2, and 3 mm) was a function of thickness, indicating that release kinetics could be controlled by the design of the cement formulation.

Antineoplastic Agents↗

Drug-drug and drug-disease interactions with nonsteroidal anti-inflammatory drugs.

Nonsteroidal anti-inflammatory drugs may cause a number of drug interactions. They can displace other drugs from serum proteins, and some can affect the metabolism or decrease the renal elimination of other drugs. In addition, they can attenuate the pharmacologic effect of other drugs, such as diuretic and antihypertensive agents, without affecting their disposition. Lastly, many disease states and aging can affect the handling of nonsteroidal anti-inflammatory drugs, mandating dose adjustment of some of these agents in certain clinical conditions. Some drugs may require more of these adjustments than others.

Aging↗

The method of relative drug accumulation: a simple method for illustrating the effects of different drug dosing regimens and variability in drug elimination on time courses of drug concentrations.

A simple method is presented for graphically illustrating time courses of relative drug concentrations and accumulation during multiple dosing. This method is based on the drug amount ratio and requires knowledge of only the elimination half-life and the dosing interval. It involves the use of relative drug concentrations, where a concentration of unity is assigned to the time-averaged concentration at steady state in a reference subject for the dosing regimen(s) being evaluated. Examples of application of the method of relative drug accumulation involve simulations of the effects of different multiple-dose regimens and variability in drug elimination on time courses of drug concentrations and drug accumulation.

Computer Simulation↗

[Cutaneous side effects of systemic drugs. Part 4 of a synopsis. 6/7. Drugs affecting the central nervous system. C. Drug-induced photosensitivity. D. Drug-induced changes of skin color].

This, the fourth part of a synopisis of cutaneous side effects of drugs, covers the drugs affecting the central nervous system: antiepileptics, hypnotics, narcotics and psychopharmaceutics; the myorelaxants and antiallergics follow, and lastly there is a section on drug addiction and placebo. The various cutaneous side effects are listed in chart form referring to more than 500 sources. A drug index is attached for handy reference. The reviews of certain drug induced skin disorders are continued with tables covering photosensitivity and changes in skin colour. Phototoxicity, photoallergy and light sensitivity by porphyria are differentiated. The various pigmentation disorders, colour changes due to metal deposits as well as different localisations are included.

Anticonvulsants↗

Drug information systems, early warning, and new drug trends: can drug monitoring systems become more sensitive to emerging trends in drug consumption?

Drug Information Systems (DIS) are called upon to provide an early warning of emerging trends in drug use. However, little theoretical attention is directed toward exploring conceptual issues in this area. In this paper a typology of existing DIS is offered. Among the features that distinguish DIS are their structure (human network or organization systems) and the range of information sources used. Indicators of drug use can be placed on a continuum of sensitivity ranging from leading edge indicators to lagged indicators. Sensitivity implies volatility as sensitive indicators also react to fluctuations that do not become trends. DIS conventionally are largely reliant upon lagged indicators. What is required are DIS that combine a critical information processing function with the ongoing systematic collection of data from a range of data sources.

Data Collection↗

Tricyclic and related drugs for nocturnal enuresis in children.

BACKGROUND: Enuresis (bedwetting) is a socially unacceptable and stressful condition which affects around 15-20% of five year olds, and up to 2% of young adults. Although there is a high rate of spontaneous remission, the social, emotional and psychological costs to the children can be great. OBJECTIVES: To assess the effects of tricyclic and related drugs on nocturnal enuresis in children, and to compare them with other interventions. SEARCH STRATEGY: The following electronic databases were searched: MEDLINE to June 1997; AMED; ASSIA; BIDS; BIOSIS Previews (1985-1996); CINAHL; DHSS Data; EMBASE (1974 to June 1997); PsycLIT and SIGLE. Organisations, manufacturers, researchers and health professionals concerned with enuresis were contacted for information. The reference sections of obtained studies were also checked for further trials. Date of the most recent search: July 1997. SELECTION CRITERIA: All randomised trials of tricyclic and related drugs for nocturnal enuresis in children were included in the review. Trials were eligible for inclusion if: children were randomised to receive tricyclics compared with placebo, other drugs or other conservative interventions for nocturnal bedwetting; participants with organic causes for their bedwetting were excluded; and baseline assessments of the level of bedwetting were provided. Trials focused solely on daytime wetting were excluded. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed the quality of the eligible trials, and extracted data. MAIN RESULTS: Twenty two randomised trials, involving 1100 children treated with tricyclic or related drugs, met the inclusion criteria. The quality of many of the trials was poor. Only single trials compared tricyclic or related drugs with each other, other drugs, desmopressin, alarms or other behavioural interventions. Treatment with tricyclic drugs (such as imipramine, amitriptyline, viloxazine, clomipramine and desipramine but not mianserin) were associated with a reduction of about one wet night per week while on treatment (eg using imipramine, WMD -0.99, 95% CI -1.27 to -0.71). Children were almost five times more likely to achieve 14 dry nights with the drugs (eg using imipramine, RR = 4.99, 95% CI 2.4 to 10.40). Desmopressin and tricyclics appeared equally effective while on treatment, but this effect was not sustained after treatment stopped. There was no detectable difference between imipramine and alarms while on treatment, but afterwards those who had used alarms had one fewer wet night per week (WMD 1.03, 95% CI 0. 19 to 1.87). REVIEWER'S CONCLUSIONS: Treatment with tricyclic drugs (imipramine, amitriptyline, viloxazine, clomipramine and desipramine but not mianserin) was associated with a reduction of about one wet night per week while on treatment, but long term effectiveness is unknown. Desmopressin and tricyclics appeared equally effective while on treatment, but this effect was not sustained after treatment stopped. Alarms may be more effective in the long term. Comparisons between drug and behavioural treatments are needed, and should include relapse rates after treatment is finished.

Antidepressive Agents, Tricyclic↗

Low molecular weight proteins as carriers for renal drug targeting. Preparation of drug-protein conjugates and drug-spacer derivatives and their catabolism in renal cortex homogenates and lysosomal lysates.

Low molecular weight proteins (LMWPs) are known to be reabsorbed and catabolized primarily by the proximal tubular cells of the kidneys. As such, LMWPs might serve as drug carriers that release drugs site-specifically in the kidney. We tested this concept in vitro by coupling different drugs to the LMWP lysozyme both directly (amide bond) and via different spacers: oligopeptides (amide bond), (poly-)alpha-hydroxy acids (ester bond), and a pH sensitive cis-aconityl spacer (amide bond). The capability of the kidney to release the parent drug from such drug-spacer derivatives and drug-LMWP conjugates by enzymatic or chemical hydrolysis of the bond was tested by incubation experiments in renal cortex homogenates and lysosomal lysates. Directly coupled conjugates of terminal carboxyl group containing drugs and lysozyme were catabolized to single amino acids, but did not result in release of the parent drug. The amide bond between the drug and the final amino acid (lysine) appeared to be stable in the incubation milieu. Different oligopeptide spacers coupled to the drugs showed similar results: the oligopeptide itself was cleaved but the amide bond between the drug and different single amino acids remained untouched. Only amide bonds of derivatives of carboxylic drugs with peptide structures themselves were cleaved. Some of the directly coupled conjugates of terminal amino drugs and oligopeptides showed clear release of the parent drug whereas others were stable. Terminal amino drugs were rapidly released from an acid-sensitive cis-aconityl spacer. Terminal carboxyl group containing drugs were enzymatically released from their glycolic and lactic ester spacers at different rates. These kinds of drugs were also released as parent drug from LMWP conjugates with ester spacers like L-lactic acid. Increasing spacer length by intercalating a tetra(L-lactic acid) molecular between the drug and the protein further increased the extent and rate of drug release, indicating increased accessibility of the bond to the enzymes. Terminal amino group containing drugs were rapidly generated as parent drug from LMWP conjugates using an acid-sensitive spacer. In addition the conjugates were found to be adequately stable in plasma, considering their rapid clearance from the bloodstream. It is concluded that LMWPs may indeed be of use as carriers for specific renal delivery of drugs, since renal cortex homogenates and lysosomal lysates are able to catabolize the protein and generate the parent drug from drug-LMWP conjugates bearing suitable spacers. The option of enzymatic release is limited by the narrow specificity of the lysosomal enzymes.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acids↗

In human therapy, is the drug-drug interaction or the adverse drug reaction the issue?

In recent years, many publications in scientific journals have reported, in healthy volunteers, potential food-drug or drug-drug interactions. The lay press has frequently emphasized such interactions and extrapolated on the dangers of food-drug or drug-drug interactions. However, the clinical relevancy of these interactions has not always been substantiated in patients. The aim of the present review was to assess the clinical relevancy of drug-drug interactions occurring at the level of the biotransformation of the drug. For this purpose, the incidence of serious, life-threatening adverse drug reactions (ADRs) of drugs metabolized by different enzymes of cytochrome P450 found in the safety reports issued in megatrials were compared with those from placebo trials. It was concluded that serious ADRs secondary to drug-drug interactions are infrequent; drug-drug interactions including selected drugs with a narrow therapeutic index and eliciting life-threatening undesired effects occur; and serious ADRs secondary to drug-drug interactions are most frequent in elderly patients, in the presence of polypharmacy, in the psychiatric patient population, and in the presence of inappropriate prescriptions and of multiple prescriptors.

Adverse Drug Reaction Reporting Systems↗