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1.
The nitroheterocyclic drugs nifurtimox and benznidazole are first-line drugs available to treat Chagas disease; however, they have limitations, including long treatment courses and toxicity. Strategies to overcome these limitations include the identification of new drugs with specific target profiles, re-dosing regimens for the current drugs, drug repositioning and combination therapy. In this work, we evaluated combination therapy as an approach for optimization of the current therapeutic regimen for Chagas disease. The curative action of benznidazole/itraconazole combinations was explored in an established infection of the mice model with the T. cruzi Y strain. The activities of the benznidazole/itraconazole combinations were compared with the results from those receiving the same dosage of each individual drug. The administration of benznidazole/itraconazole in combination eliminated parasites from the blood more efficiently than each drug alone. Here, there was a significant reduction of the number of treatment days (number of doses) necessary to induce parasitemia suppression with the benznidazole/itraconazole combination, as compared to each compound administered alone. These results clearly indicate the enhanced effects of these drugs in combination, particularly at the dose of 75 mg/kg, as the effects observed with the drug combinations were four times more effective than those of each drug used alone. Moreover, benznidazole/itraconazole treatment was shown to prevent or decrease the typical lesions associated with chronic experimental Chagas disease, as illustrated by similar levels of inflammatory cells and fibrosis in the cardiac muscle tissue of healthy and treated mice. These results emphasize the importance of exploring the potential of combination treatments with currently available compounds to specifically treat Chagas disease.  相似文献   

2.
Optimizing combination chemotherapy by controlling drug ratios   总被引:1,自引:0,他引:1  
Cancer chemotherapy treatments typically employ drug combinations in which the dose of each agent is pushed to the brink of unacceptable toxicity; however, emerging evidence indicates that this approach may not be providing optimal efficacy due to the manner in which drugs interact. Specifically, whereas certain ratios of combined drugs can be synergistic, other ratios of the same agents may be antagonistic, implying that the most efficacious combinations may be those that utilize certain agents at reduced doses. Advances in nano-scale drug delivery vehicles now enable the translation of in vitro information on synergistic drug ratios into improved anticancer combination therapies in which the desired drug ratio can be controlled and maintained following administration in vivo, so that synergistic effects can be exploited. This "ratiometric" approach to combination chemotherapy opens new opportunities to enhance the effectiveness of existing and future treatment regimens across a spectrum of human diseases.  相似文献   

3.
In Parkinson''s disease, the long-term use of dopamine replacing agents is associated with the development of motor complications; therefore, there is a need for non-dopaminergic drugs. This study evaluated the potential therapeutic impact of six different NR2B and A2A receptor antagonists given either alone or in combination in unilateral 6-OHDA-lesioned rats without (monotherapy) or with (add-on therapy) the co-administration of L-Dopa: Sch-58261+ Merck 22; Sch-58261+Co-101244; Preladenant + Merck 22; Preladenant + Radiprodil; Tozadenant + Radiprodil; Istradefylline + Co-101244. Animals given monotherapy were assessed on distance traveled and rearing, whereas those given add-on therapy were assessed on contralateral rotations. Three-way mixed ANOVA were conducted to assess the main effect of each drug separately and to determine whether any interaction between two drugs was additive or synergistic. Additional post hoc analyses were conducted to compare the effect of the combination with the effect of the drugs alone. Motor activity improved significantly and was sustained for longer when the drugs were given in combination than when administered separately at the same dose. Similarly, when tested as add-on treatment to L-Dopa, the combinations resulted in higher levels of contralateral rotation in comparison to the single drugs. Of special interest, the activity observed with some combinations could not be described by a simplistic additive effect and involved more subtle synergistic pharmacological interactions. The combined administration of A2A/NR2B-receptor antagonists improved motor behaviour in 6-OHDA rats. Given the proven translatability of this model such a combination may be expected to be effective in improving motor symptoms in patients.  相似文献   

4.
The aim of the study was to evaluate precisely the type of interactions between mexiletine (an antiarrhythmic drug) and four new generation antiepileptic drugs: lamotrigine, oxcarbazepine, topiramate and pregabalin in the maximal electroshock test in mice (MES). The isobolographic analysis was used to assess the nature of interactions between the tested drugs. Total brain concentrations of antiepileptics were also measured to detect possible pharmacokinetic interactions. The results obtained indicated that the mixture of mexiletine and pregabalin at the fixed ratios of 1:1 and 3:1 led to supra-additive interaction in terms of seizure suppression, while the proportion of 1:3 occurred additive. Synergism was also demonstrated for the combination of mexiletine and topiramate in all three proportions. Combinations of mexiletine with lamotrigine and mexiletine with oxcarbazepine were found to be additive. Adverse-effect profiles of mexiletine, antiepileptics and drug combinations were evaluated in the chimney test (motor coordination) and step-through passive-avoidance task (long-term memory). Mexiletine and drug combinations did not impair long-term memory. Moreover, all combinations of mexiletine with lamotrigine, oxcarbazepine and topiramate had no significant effect on motor coordination. However, the results from the chimney test indicated that pregabalin, administered alone at its ED50 dose from the MES-test, significantly impaired motor performance. Similar adverse effects were observed when mexiletine was co-administered with pregabalin at the fixed-dose ratio combinations of 1:1 and 1:3. However, reduction of pregabalin dose at the fixed ratio of 3:1 seems to prevent significant motor impairment. The results may indicate that mexiletine can be considered as an adjunctive drug in antiepileptic treatment, particularly in patients with concomitant cardiac arrhythmia.  相似文献   

5.
We investigated the effect of peripherally administered caffeine (50 mg/kg), choline (30, 60, or 120 mg/kg) or combinations of both drugs on the spontaneous release of acetylcholine (ACh) from the corpus striatum of anesthetized rats using in vivo microdialysis. Caffeine alone or choline in the 30 or 60 mg/kg dose failed to increase ACh in microdialysis samples; the 120 mg/kg choline dose significantly enhanced ACh during the 80 min following drug administration. Coadministration of caffeine with choline significantly increased ACh release after each of the choline doses tested. Peak microdialysate levels with the 120 mg/kg dose were increased 112% when caffeine was additionally administered, as compared with 54% without caffeine. These results indicate that choline administration can enhance spontaneous ACh release from neurons, and that caffeine, a drug known to block adenosine receptors on these neurons, can amplify the choline effect.  相似文献   

6.
The ability to quantitatively predict the influence of a solubilization technology on oral absorption would be highly beneficial in rational selection of drug delivery technology and formulation design. Cyclodextrins (CDs) are cyclic oligosaccharides which form inclusion complexes with a large variety of compounds including drugs. There are many studies in the literature showing that complexation between CD and drug enhances oral bioavailability and some demonstrating failure of CD in bioavailability enhancement, but relatively little guidance regarding when CD can be used to enhance bioavailability. A model was developed based upon mass transport expressions for drug dissolution and absorption and a pseudo‐equilibrium assumption for the complexation reaction with CD. The model considers neutral compound delivered as a physical mixture with CD in both immediate release (IR) and controlled release (CR) formulations. Simulation results demonstrated that cyclodextrins can enhance, have no effect, or hurt drug absorption when delivered as a physical mixture with drug. The predicted influence depends on interacting parameter values, including solubility, drug absorption constant, binding constant, CD:drug molar ratio, dose, and assumed volume of the intestinal lumen. In general, the predicted positive influence of dosing as a physical mixture with CD was minimal, alluding to the significance of dosing as a preformed complex. The model developed enabled examination of which physical and chemical properties result in oral absorption enhancement for neutral drug administered as a physical mixture with CD, demonstrating the utility of modeling the influence of a drug delivery agent (e.g., CD) on absorption for rational dosage form design. Biotechnol. Bioeng. 2010; 105: 409–420. © 2009 Wiley Periodicals, Inc.  相似文献   

7.
Human diseases may involve cellular signaling networks that contain redundant pathways, so that blocking a single pathway in the system cannot achieve the desired effect. As such, the use of drugs in combination are particularly effective interventions in networked systems. However, common synergy measures are often inadequate to quantify the effect of two different drugs in complex cellular systems. This article proposes a general approach to quantifying the synergy of two drugs in combination. This approach is called strong nonlinear blending. Drugs with different relative potencies, different effect maxima, or situations of potentiation or coalism pose no problem for strong nonlinear blending as a way to assess the increased response benefit to be gained by combining two drugs. This is important as testing drug combinations in complex biological systems are likely to produce a wide variety of possible response surfaces. It is also shown that for monotone increasing (or decreasing) dose response surfaces that strong nonlinear blending is equivalent to improved potency along a ray of constant dose ratio. This is important because fixed dose ratios form the basis for many preclinical and clinical combination drug experiments. Two examples are given involving HIV and cancer chemotherapy combination drug experiments.  相似文献   

8.

Background

There are no drugs presently available to treat traumatic brain injury (TBI). A variety of single drugs have failed clinical trials suggesting a role for drug combinations. Drug combinations acting synergistically often provide the greatest combination of potency and safety. The drugs examined (minocycline (MINO), N-acetylcysteine (NAC), simvastatin, cyclosporine A, and progesterone) had FDA-approval for uses other than TBI and limited brain injury in experimental TBI models.

Methodology/Principal Findings

Drugs were dosed one hour after injury using the controlled cortical impact (CCI) TBI model in adult rats. One week later, drugs were tested for efficacy and drug combinations tested for synergy on a hierarchy of behavioral tests that included active place avoidance testing. As monotherapy, only MINO improved acquisition of the massed version of active place avoidance that required memory lasting less than two hours. MINO-treated animals, however, were impaired during the spaced version of the same avoidance task that required 24-hour memory retention. Co-administration of NAC with MINO synergistically improved spaced learning. Examination of brain histology 2 weeks after injury suggested that MINO plus NAC preserved white, but not grey matter, since lesion volume was unaffected, yet myelin loss was attenuated. When dosed 3 hours before injury, MINO plus NAC as single drugs had no effect on interleukin-1 formation; together they synergistically lowered interleukin-1 levels. This effect on interleukin-1 was not observed when the drugs were dosed one hour after injury.

Conclusions/Significance

These observations suggest a potentially valuable role for MINO plus NAC to treat TBI.  相似文献   

9.
Human diseases may involve cellular signaling networks that contain redundant pathways, so that blocking a single pathway in the system cannot achieve the desired effect. As such, the use of drugs in combination are particularly effective interventions in networked systems. However, common synergy measures are often inadequate to quantify the effect of two different drugs in complex cellular systems. This article proposes a general approach to quantifying the synergy of two drugs in combination. This approach is called strong nonlinear blending. Drugs with different relative potencies, different effect maxima, or situations of potentiation or coalism pose no problem for strong nonlinear blending as a way to assess the increased response benefit to be gained by combining two drugs. This is important as testing drug combinations in complex biological systems are likely to produce a wide variety of possible response surfaces. It is also shown that for monotone increasing (or decreasing) dose response surfaces that strong nonlinear blending is equivalent to improved potency along a ray of constant dose ratio. This is important because fixed dose ratios form the basis for many preclinical and clinical combination drug experiments. Two examples are given involving HIV and cancer chemotherapy combination drug experiments.  相似文献   

10.

Background

Current chemotherapy for Chagas disease is unsatisfactory due to its limited efficacy, particularly in the chronic phase, with frequent side effects that can lead to treatment discontinuation. Combined therapy is envisioned as an ideal approach since it may improve treatment efficacy whilst decreasing toxicity and the likelihood of resistance development. We evaluated the efficacy of posaconazole in combination with benznidazole on Trypanosoma cruzi infection in vivo.

Methods and Findings

Benznidazole and posaconazole were administered individually or in combination in an experimental acute murine infection model. Using a rapid treatment protocol for 7 days, the combined treatments were more efficacious in reducing parasitemia levels than the drugs given alone, with the effects most evident in combinations of sub-optimal doses of the drugs. Subsequently, the curative action of these drug combinations was investigated, using the same infection model and 25, 50, 75 or 100 mg/kg/day (mpk) of benznidazole in combination with 5, 10 or 20 mpk of posaconazole, given alone or concomitantly for 20 days. The effects of the combination treatments on parasitological cures were higher than the sum of such effects when the drugs were administered separately at the same doses, indicating synergistic activity. Finally, sequential therapy experiments were carried out with benznidazole or posaconazole over a short interval (10 days), followed by the second drug administered for the same period of time. It was found that the sequence of benznidazole (100 mpk) followed by posaconazole (20 mpk) provided cure rates comparable to those obtained with the full (20 days) treatments with either drug alone, and no cure was observed for the short treatments with drugs given alone.

Conclusions

Our data demonstrate the importance of investigating the potential beneficial effects of combination treatments with marketed compounds, and showed that combinations of benznidazole with posaconazole have a positive interaction in murine models of Chagas disease.  相似文献   

11.
Drug combinations are common in cancer treatment and are rapidly evolving, moving beyond chemotherapy combinations to combinations of signal transduction inhibitors. For the delivery of drug combinations, i.e., multi-drug delivery, major considerations are synergy, dose regimen (concurrent versus sequential), pharmacokinetics, toxicity, and safety. In this contribution, we review recent research on polymeric micelles for multi-drug delivery in cancer. In concurrent drug delivery, polymeric micelles deliver multi-poorly water-soluble anticancer agents, satisfying strict requirements in solubility, stability, and safety. In sequential drug delivery, polymeric micelles participate in pretreatment strategies that “prime” solid tumors and enhance the penetration of secondarily administered anticancer agent or nanocarrier. The improved delivery of multiple poorly water-soluble anticancer agents by polymeric micelles via concurrent or sequential regimens offers novel and interesting strategies for drug combinations in cancer treatment.KEY WORDS: controlled release, drug combination, drug delivery, drug solubilization, polymeric micelles  相似文献   

12.
Hydralazine, labetalol, methyldopa, minoxidil, prazosin, and placebo were compared when added by random allocation to atenolol 100 mg and bendrofluazide 5 mg daily in a series of 238 hypertensive patients inadequately controlled by the beta blocker-diuretic combination. Atenolol was withdrawn in those allocated to labetalol, and minoxidil was given only to men. The order of acceptability was: placebo, hydralazine, prazosin, methyldopa, minoxidil, labetalol. Minoxidil was more effective than the other active drugs, which had similar potency to one another. All the active agents were more effective than placebo. Hydralazine was the most generally suitable third drug, with prazosin a close second. Minoxidil was especially effective in patients with less severe hypertension but the same regimen caused fluid retention in those with more severe disease. Labetalol should probably be introduced at a low dose (150 mg daily) even when replacing full doses of a previously administered beta blocker.  相似文献   

13.
Singh VP  Patil CS  Kulkarni SK 《Life sciences》2006,78(11):1168-1174
Drug combinations have the potential advantage of greater analgesia over monotherapy. The present study was aimed to assess any possible interaction (additive or potentiation) in the antinociceptive effects of etoricoxib; a novel cyclooxygenase-2 inhibitor, and tramadol; a typical opioid agonist when administered in combination against mechanical hyperalgesia induced by spinal cord injury in rats. The nature of interaction was analyzed using surface of synergistic interaction (SSI) analysis and an isobolographic analysis. Etoricoxib or tramadol when administered alone to rats, exhibited different antihyperalgesic potencies (ED50 etoricoxib: 0.58+/-0.19 mg/kg, po; ED50 tramadol: 9.85+/-0.57 mg/kg, po). However, both the drugs were found to be long acting against this model of hyperalgesia. Further, etoricoxib and tramadol were co-administered in fixed ratios of ED50 fractions. One combination (0.29/4.79 mg/kg, po: etoricoxib/tramadol) exhibited additivity and other three combinations (0.15/2.39, 0.08/1.19, and 0.04/0.59 mg/kg, po: etoricoxib/tramadol) resulted in potentiation when analyzed by SSI. The SSI was calculated from the total antihyperalgesic effect produced by the combination after the subtraction of the antihyperalgesic effect produced by each of the individual drug. In the isobolographic analysis, the experimental ED50 was found to be far below the line of additivity also indicating a significant (P < 0.05) synergistic antihyperalgesic effect when etoricoxib and tramadol was co-administered to rats. The synergistic antihyperalgesic effect of etoricoxib and tramadol combination suggests that these combinations may have clinical utility in mechanical hyperalgesia associated with spinal injury.  相似文献   

14.
J E Morley  J F Flood 《Life sciences》1987,41(18):2157-2165
This study compared the effects of chronic administration of anorexigenic drugs on weight loss in mice. Tolerance to the effects of peripheral anorexigenic peptides, viz. cholecystokinin-octapeptide and bombesin, developed rapidly. Morphine, cocaine and dehydroepiandrosterone-sulfate caused weight loss and appeared similar to d-amphetamine in mechanisms of action. A high dose of fluoxetine (25 mg/kg) proved to be a potent leptogenic agent but was also associated with death in some animals. A lower dose of fluoxetine (5 mg/kg) was associated with the development of tolerance. Calcitonin, a potent anorexigenic agent, did not produce weight loss and tolerance to its anorectic effect had developed by 10 days. Animals varied widely in their individual responsiveness to a given drug. Peripheral administration of peptide YY caused weight loss. We conclude that acute or chronic effects of agents on food intake do not necessarily predict effects on body weight. However, neurotransmitters that enhance feeding centrally appear to cause weight loss when administered peripherally.  相似文献   

15.
The efficacy of pefloxacin in the complex treatment of 28 patients with pancreatonecrosis of various etiology was estimated in a prospective trial. The diagnosis of pancreatonecrosis was verified by the data of the disease clinical progress, laboratory findings and instrumental examination. Pefloxacin (Abactal; LEK) was administered intravenously in a dose of 400 mg every 8 hours (1200 mg) in combination with metronidazole in a dose of 1.5-2.0 g a day intravenously. When indicated 3 days after the start of the pefloxacin therapy, the treatment was switched to the oral use of the drug in the same dosage. The positive clinical effect (cure and improvement) at the end of the treatment with pefloxacin was stated in 78 per cent of the patients in spite of the initial severity state of above 15 APACHE II. It was shown that in the treatment of patients with pancreatonecrosis when the severity state was not above 12 APACHE II the antibacterial therapy with pefloxacin in combination with metronidazole was optimal.  相似文献   

16.
Paclitaxel (PTX) and gemcitabine (GEM) are often used in combination due to the synergistic anticancer effects. PTX and GEM combination showed a synergistic effect to SKOV-3 cells at a molar ratio of 1 to 1 and in PTX ? GEM sequence. Liposomes were explored as a carrier of PTX and GEM combination. We optimized the drug loading in liposomes varying the preparation method and co-encapsulated PTX and GEM in a single liposome preparation maintaining the maximum loading efficiency of each drug. However, drug release kinetics from the co-loaded liposomes (LpPG) was suboptimal because of the detrimental effect of PTX on GEM-release control. Instead, a mixture of LpP and LpG, which were separately optimized according to the desired release kinetics, achieved a greater cytotoxic effect than LpPG, due to the attenuation of GEM release relative to PTX. This study illustrates that co-encapsulation in a single carrier is not always desirable for the delivery of drug combinations, when the activity depends on the dosing sequence. These combinations may benefit from the mixed liposome approach, which offers greater flexibility in controlling the ratio and release kinetics of component drugs.  相似文献   

17.
Fungal infection has become one of the leading causes of hospital-acquired infections with high mortality rates. Furthermore, drug resistance is common for fungus-causing diseases. Synergistic drug combinations could provide an effective strategy to overcome drug resistance. Meanwhile, synergistic drug combinations can increase treatment efficacy and decrease drug dosage to avoid toxicity. Therefore, computational prediction of synergistic drug combinations for fungus-causing diseases becomes attractive. In this study, we proposed similar nature of drug combinations: principal drugs which obtain synergistic effect with similar adjuvant drugs are often similar and vice versa. Furthermore, we developed a novel algorithm termed Network-based Laplacian regularized Least Square Synergistic drug combination prediction (NLLSS) to predict potential synergistic drug combinations by integrating different kinds of information such as known synergistic drug combinations, drug-target interactions, and drug chemical structures. We applied NLLSS to predict antifungal synergistic drug combinations and showed that it achieved excellent performance both in terms of cross validation and independent prediction. Finally, we performed biological experiments for fungal pathogen Candida albicans to confirm 7 out of 13 predicted antifungal synergistic drug combinations. NLLSS provides an efficient strategy to identify potential synergistic antifungal combinations.  相似文献   

18.
Sea lice are a major problem in Norwegian fish farms; however, data on drug treatment patterns or treatment rates of sea lice infestations are not available. Such data are important for analysing resistance patterns against drugs used for such infestations. The main objective of the present study was to develop a method to estimate the treatment patterns and treatment rates for drugs used in the treatment against sea lice (Lepeophtheirus salmonis and Caligus elongatus) in farm salmonids by means of national sales statistics. Annual sales figures, as weight of active substances, were obtained from the drug wholesalers and the feed mills. The weight of active drug substances is not useful as a unit of measurement of drug use in an epidemiological context because it does not correct for dosage differences and number of repeat treatments. To correct for these factors, we introduced approved daily dose (ADD(farm fish)) and treatment course-doses(farm fish) kg(-1) live-weight fish. To express the drug treatment patterns, the biomass (in weight) of farm salmonids treated with 1 course of a drug were estimated. When measured as kg active substance, the quantities of drugs for the treatment of sea lice infestations declined by 98% during the study period (1989 to 2002) but this figure increased 5-fold when it was corrected for differences in dosage. To correct for amounts of farm salmonids liable to require treatment we estimated the annual treatment rate, defined as the number of treatments for sea lice infestations per biomass slaughtered Atlantic salmon Salmo salar and rainbow trout Oncorhynchus mykiss. The annual treatment rate increased gradually during the study period; however, it varied considerably (range 0.45 to 1.34, mean 0.90). Before 1995, organophosphates were the most frequently used drugs against sea lice; since then pyrethroids have become the dominating drug group.  相似文献   

19.
Thirteen analgesic drugs, four of them at two dose levels, four analgesics in combination with antagonist or neuroleptic agents, and saline have been evaluated simultaneously in the relief of postoperative pain. The method of assessment was designed to favour drugs which provided freedom from pain with minimum depression of consciousness. Only levorphanol 2 mg proved significantly superior to pethidine 100 mg, which was used as the standard reference drug. Oxycodone 10 mg, pentazocine 20 mg, and the morphine 10 mg and cyclizine 50 mg combination were the most successful of the remaining drugs. None of the drug combinations was significantly better than the analgesic drug given alone.  相似文献   

20.
The efficacy of various combinations of atenolol, bendrofluazide, and hydraliazine given twice daily was assessed in a double-blind trial on 39 patients with moderate to severe essential hypertension. Concurrent treatment with all three drugs proved most effective and produced a mean reduction in blood pressure of 43/31 mm Hg. In the dosage used, hydrallazine affected only the diastolic blood pressure, and when added to either bendrofluazide or bendrofluazide plus atenolol it produced a further mean reduction in pressure of 6 mm Hg. Once-daily treatment with atenolol and bendrofluazide was as effective in reducing blood pressure as the same combination given twice daily, and the hypotensive effect was still present at least 24 hours after the last dose of tablets. A combined tablet of atenolol and bendrofluazide taken once daily would be a simple regimen to follow and would provide almost as much hypotensive effect as a twice-daily regimen incorporating a modest dose of hydrallazine. The hypotensive effect of atenolol was equal to that of bendrofluazide on systolic pressure but significantly better than that of bendrofluazide on diastolic pressure. Atenolol reduced plasma renin and urate concentrations but increased plasma potassium levels. The biochemical effects of atenolol, therefore, may be an advantage over those of bendrofluazide when deciding on first-line treatment for essential hypertension.  相似文献   

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