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Treatment of gonorrhea with trimethoprim-sulfamethoxazole.
The following regimens were randomly administered to 271 men with gonococcal urethritis: 4.8 X 10(6) units of aqueous procaine penicillin G intramuscularly plus 1 g of probenecid orally (APPG); nine tablets of trimethoprim-sulfamethoxazole (TMP-SMZ; 720 mg of TMP and 3,600 mg of SMZ), orally as a single dose (TMP-SMZ-9); and 12 tablets of TMP-SMZ (960 mg of TMP and 4,800 mg of SMZ) orally as two doses of six tablets taken at a 6-hr interval (TMP-SMZ-12). The failure rates of the APPG, TMP-SMZ-9, and TMP-SMZ-12 regimens were 4%, 23%, and 19%, respectively. APPG was significantly more effective (P less than 0.05) than TMP-SMZ-9 or TMP-SMZ-12. Isolates of Neisseria gonorrhoeae from treatment failures as compared to those from treatment successes were significantly more resistant to SMZ (P less than 0.01) and to the TMP-SMZ combination in a ratio of 19 parts SMZ to one part TMP (P less than 0.05). Minimal inhibitory concentrations of SMZ, TMP, TMP-SMZ, and penicillin G showed positive correlation coefficients.
Genome-wide identification of conditionally essential genes for growth in the presence of sulfamethoxazole and trimethoprim in sulfamethoxazole- and trimethoprim-resistant Escherichia coli.
UNLABELLED: Resistance to sulfonamides (SULs) and trimethoprim (TMP) in Escherichia coli threatens their clinical relevance. Beyond known resistance mechanisms, little is understood about the cellular responses that enable resistant E. coli to grow under these antibiotic stresses. This study aimed to identify genes that support bacterial growth under SUL and TMP stress. Two saturated transposon mutant libraries were constructed in resistant E. coli MG1655 harboring either dfrA1 or sul2. They were grown with and without 1/2 and 1/4 minimum inhibitory concentration (MIC) of sulfamethoxazole (SMX) or TMP, and mutant depletion was assessed via transposon-directed insertion-site sequencing. At 1/2 MIC, 36 and 89 genes were identified as conditionally essential during SMX and TMP exposure, while 5 and 2 genes were classified as conditionally essential at 1/4 MIC. Genes identified as conditionally essential at 1/4 MIC were also important at 1/2 MIC. Conditionally essential genes belonged to lipopolysaccharide biosynthesis, peptidoglycan metabolism, energy production, membrane integrity, phosphate metabolism, and stress responses, highlighting the role of these factors in maintaining cell stability under SMX and TMP stress. Validation with 10 conditionally essential genes (apaH, mtn, surA, waaO, nlpI, prc, wzxE, fadR, degP, and tpiA) showed that deletion mutants indeed exhibited growth defects and two- to eightfold reductions in MIC under antibiotic stresses compared to their parent strains. This study highlights cellular responses to SMX and TMP under antibiotic stress, and it has identified a list of genes whose products may serve as potential helper drug targets to resensitize resistant E. coli to SMX and TMP treatments. IMPORTANCE: Sulfonamides (SULs) and trimethoprim (TMP) are broad-spectrum antimicrobials. They are commonly used to treat infections in both humans and animals. Resistance against SUL and TMP is widespread in pathogenic bacteria, and there is a need to overcome this problem. One possibility is to target the cellular mechanism by which the resistant bacteria adapt to growth in the presence of the antimicrobials. In this study, we identify the genes, besides the resistance genes, which enable resistant Escherichia coli to grow in the presence of SUL and TMP. We further show that knocking out many of these genes attenuates the resistant E. coli for growth during SUL and/or TMP stress, irrespective of which SUL- or TMP-resistant gene the bacteria carry. The gene products of these genes may serve as potential helper drug targets to resensitize resistant E. coli to sulfamethoxazole and TMP treatments.
Pharmacokinetics of sulfadiazine and trimethoprim in man.
Sulfadiazine (SDZ) 800 mg and trimethoprim (TMP) 160 mg were given orally to 10 normal subjects and the concentration of SDZ and TMP in serum and urine was followed for 24 h. Both drugs showed a significant negative correlation between individual "peak" concentrations in serum and the body weight of the subject. Twelve hours after dosing the serum concentration was 12 to 25 microgram/ml for SDZ and 0.3 to 1.1 microgram/ml for TMP. Individual concentration ratios between SDZ and TMP in serum were 4.8 (1 h)--145 (24 h), and in the urine the ratio was close to 6 throughout the 24 h collection period. The range of urinary concentrations was from 65 to 400 microgram/ml for SDZ and from 13.8 to 93.4 microgram/ml for TMP. The fraction (formula: see text) was 21% during the 0--8 h period, 33% during the 8--15 h period and 41% during the 15--24 period. The average "t1/2" was 15.2 +/- 7.4 h for SDZ and 7.4 +/- 1.9 h for TMP. Individual subjects showed a significant correlation between the serum clearance of TMP and SDZ (p less than 0.01) and also between the renal clearance of the two drugs (p less than 0.05). The serum clearance was significantly correlated with the renal clearance for TMP but not for SDZ. For SDZ Vd was significantly negatively correlated with the elimination constant; for TMP no such correlation was found. The serum clearance of SDZ was significantly correlated with the percentage of SDZ which was excreted as the (presumably) acetylated compound. The renal clearance of SDZ was independent of the serum concentration of SDZ. There was a highly significant negative correlation between the renal clearance and serum concentration of TMP, as well as for "acetylated SDZ". The renal clearance of "acetylated SDZ" averaged more than six times that of unconjugated SDZ. With increased urine flow the renal clearances of TMP and SDZ were significantly increased.
The effect of trimethoprim and sulfamethoxazole on Toxoplasma gondii in vitro and in vivo.
Trimethoprim (TMP) and sulfamethoxazole (SMZ) were studied alone and in combination to determine their effect in vitro on intracellular Toxoplasma gondii and in vivo against murine toxoplasmosis. In the in vitro experiments, whereas 1 and 2 microgram/ml TMP had no demonstrable effect on intracellular T. gondii, 10-20 microgram/ml TMP resulted in death of the intracellular organisms; concentrations as high as 100 microgram/ml SMZ had no demonstrable effect against the intracellular organisms. When used in combination, a significant synergistic effect was noted with 2 microgram/ml TMP-50 microgram/ml SMZ. Studies on the kinetics of inhibition and/or killing of Toxoplasma revealed that 18 hours of treatment with 2 microgram/ml TMP-50 microgram/ml SMZ resulted in irreversible inhibition of the intracellular organisms. When used in vivo against a 50,000 LD100 dose of Toxoplasma, TMP fed by gavage or mixed in the diet had no effect in murine toxoplasmosis at doses as high as 200 mg/kg a day. SMZ administered by gavage had no effect at doses up to 200 mg/kg a day; but at 300 and 400 mg/kg SMZ, protection was 47% and 83%, respectively. Treatment of infected mice was continued for 14 consecutive days, whether the drugs were administered alone or in combination. The combination 200 mg/kg TMP-200 mg/kg SMZ, when administered by gavage, protected 87% of mice. Survival after 14 days of SMZ mixed in the diet was 0% at 100 mg/kg, 47% at 200 mg/kg, and 100% at 300 mg/kg. Survival with the combination was 40% for 200 mg/kg TMP-100 mg/kg SMZ and 100% for 100 mg/kg TMP-200 mg/kg SMZ. The half-life of TMP in serum of Swiss Webster mice was calculated to be 24 min. The results obtained in vivo were inferior to those obtainable with the combination of pyrimethamine plus sulfadiazine. The problems of interpretation of results obtained in the murine model using TMP-SMZ and in their extrapolation to the treatment of the infection in man are discussed.
Pathway of thiamine pyrophosphate synthesis in Micrococcus denitrificans.
The pathway of thiamine pyrophosphate (TPP) biosynthesis, which is formed either from exogeneously added thiamine or from the pyrimidine and thiazole moieties of thiamine, in Micrococcus denitrificans was investigated. The following indirect evidence shows that thiamine pyrophosphokinase (EC 2.7.6.2) catalyzes the synthesis of TPP from thiamine: (i) [35S]thiamine incubated with cells of this microorganism was detected in the form of [35S]thiamine; (ii) thiamine gave a much faster rate of TPP synthesis than thiamine monophosphate (TMP) when determined with the extracts; and (iii) a partially purified preparation of the extracts can use thiamine, but not TMP, as the substrate. The activities of the four enzymes involved in TMP synthesis from pyrimidine and thiazole moieties of thiamine were detected in the extracts of M. denitrificans. The extracts contained a high activity of the phosphatase, probably specific for TMP. After M. denitrificans cells were grown on a minimal medium containing 3 mM adenosine, which causes derepression of de novo thiamine biosynthesis in Escherichia coli, the activities of the four enzymes involved with TMP synthesis, the TMP phosphatase, and the thiamine pyrophosphokinase were enhanced two- to threefold. These results indicate that TPP is synthesized directly from thiamine without forming TMP as an intermediate and that de novo synthesis of TPP from the pyrimidine and thiazole moieties involves the formation of TMP, followed by hydrolysis to thiamine, which is then converted to TPP directly. Thus, the pathway of TPP synthesis from TMP synthesized de novo in M. denitrificans is different from that found in E. coli, in which TMP synthesized de novo is converted directly to TPP without producing thiamine.
[Comparison of pharmacokinetics of the combination trimethoprim and sulfamethoxazole in patients with liver diseases and healthy persons].
Pharmacokinetic characteristics of the antibacterial combination sulfamethoxazole (SMZ) plus trimethoprim (TMP) have been compared, following a single oral dose of 800 mg SMZ plus 160 mg TMP, between 3 groups of adult humans: A = 13 healthy persons, B = 4 patients with minor hepatic injury and C = 7 patients with severe, decompensated liver damage. The following data were determined: 1. the time tmax; 2. the maximum concentrations (cmax) of the two drugs reached in the plasma; 3. the half-life t1/2 of their elimination from the plasma; 4. their apparent distribution volume indicated in percent of body weight; 5. the share of metabolized SMZ in percent of total sulfonamide; 6. the concentration ratio of active SMZ to TMP, both total and unbound to plasma proteins; 7. the cumulative renal excretion of total sulfonamide and of non-metabolized TMP. Only the following differences between groups were observed: 1. The maximum plasma level of active SMZ as well as TMP was lower by an average factor of 1.5 to 2.0 in the two groups B and C as compared to group A. An analogous but diminishing difference lasted for the active SMZ up to the 24th, for TMP up to the 12th hour following medication. An influence of the liver disease on the absorption rate via alteration of the biliary conditions is envisaged as a possible explanation. 2. The elimination half-life of TMP, although lying in most of the liver patients within the range of healthy persons, was lengthened up to twice normal in some of the patients with severe liver damage. Such unusually long half-lives for TMP, however, are considered to be in the range of an individual peculiarity. 3. The renal excretion of TMP occurred in the liver-diseased patients on the average more slowly during the first 24 h and its cumulative value reached at the end of the 72 h observation time was somewhat lower than in the healthy persons. In group C at least this may be in connection with a concomitant reduction of the kidney function. None of the features indicated are considered to be of essential clinical importance, such as to discourage the use of the combination in cases of liver disease.
Double-blind comparison of sulphonamide-trimethoprim combinations in acute uncomplicated urinary tract infections.
The effects of a twice daily dosage of a combination of 410 mg sulphadiazine + 90 mg trimethoprim (SD + TMP) and 800 mg sulphamethoxazole + 160 mg trimethoprim (SMZ + TMP) were compared in uncomplicated urinary tract infections. All but one patient in each treatment group, i.e. 36 SD + TMP treated and 42 SMZ + TMP treated patients respectively, were cured. The percentage of side-effects related to therapy in the patients receiving the combination with sulphadiazine was 15.1% and in those with sulphamethoxazole 23.7%. Due to the small number tested, however, differences were not statistically different. It is noteworthy that only one of the SD + TMP patients had to stop therapy because of a rash, whereas therapy was stopped for this reason in three of the SMZ + TMP patients. SD + TMP represents a good alternative to SMZ + TMP in the treatment of urinary tract infections.
Biochemical determinants of tumor sensitivity to 5-fluorouracil: ultrasensitive methods for the determination of 5-fluoro-2'-deoxyuridylate, 2'-deoxyuridylate, and thymidylate synthetase.
Techniques have been developed to measure FdUMP, the active metabolite of 5-FUra; thymidylate synthetase (TMP synthase; 5,10-methylenetetrahydrofolate:dUMP C-methyltransferase, EC 2.1.1.45), the target enzyme for this antimetabolite; and dUMP, the substrate that competes with FdUMP for binding to TMP synthetase. As little as 0.02 pmol of FdUMP can be quantitated with a competitive ligand binding assay by using homogeneous Lactobacillus casei/MTX TMP synthetase as a binding protein. A new binding assay for TMP synthetase allows detection of 0.005 pmol of enzyme. The quantitative enzymatic conversion of dUMP to [methyl-(14)C]-TMP using 5,10-methylene[(14)C]tetrahydrofolate by pure L. casei TMP synthetase is used as an assay for dUMP with a sensitivity of 10 pmol. Cultured CCRF-CEM human lymphoblastic leukemia cells formed high levels of FdUMP (2.6 nmol per 10(9) cells) within 11 hr after exposure to 30 muM 5-FUra. Tumor cell TMP synthetase levels dropped, and then free FdUMP appeared. The intracellular dUMP pool was low (2-5 nmol per 10(9) cells) in logarithmically growing cultures of several tumor cell lines but expanded rapidly in CCRF-CEM cells on exposure to 5-FUra after enzyme levels decreased. The levels of dUMP found after exposure to 5-FUra are sufficient to severely retard inhibition of TMP synthetase by FdUMP.The methods described are sufficiently sensitive to allow these biochemical parameters of 5-FUra action to be measured in cell culture or in needle biopsy samples of human tumors.
Pharmacokinetics and tolerance of a single twelve-tablet dose of trimethoprim (960 mg)-sulfamethoxazole (4,800 mg).
To evaluate the potential usefulness of a single large oral dose of trimethoprim-sulfamethoxazole (TMP-SMZ) for the treatment of uncomplicated genitourinary gonorrhea, the pharmacokinetics of a 12-tablet dose containing 960 mg of TMP and 4,800 mg of SMZ were studied in 15 male volunteers, and the tolerance of this regimen was compared to that of a placebo in a double-blind crossover study. Both TMP and SMZ were rapidly absorbed. Peak mean serum concentrations (+/- standard deviation) of TMP, total SMZ, and free SMZ were 9.2 +/- 2.2, 259.4 +/- 40.9, and 233.7 +/- 33.6 mug/ml, respectively. Elimination half-lives were 16.7, 14.6, and 12.9 h, respectively. When results were compared to data from similar studies after smaller doses, peak mean serum concentrations were proportional to dose, but elimination half-lives were longer after larger doses. Urinary concentrations of TMP, total SMZ, and free SMZ were many-fold higher than serum concentrations. Percents recovery (+/- standard deviation) in urine were 60.6 +/- 10.6, 80.2 +/- 7.8, and 37.4 +/- 6.5%, respectively, during the 48 h after administration. The incidence of severe headache and of objective transient oliguria was significantly higher after TMP-SMZ than after placebo. Although the observed serum concentrations of TMP and SMZ surpassed concentrations necessary to inhibit clinical isolates of Neisseria gonorrhoeae in vitro for longer than 24 h, the adverse reactions associated with a 12-tablet dose of TMP-SMZ would preclude the clinical usefulness of such a therapeutic regimen.
Pharmacokinetics of sulphadiazine, sulphamethoxazole and trimethoprim in patients with varying renal function.
The pharmacokinetics of tablets containing combinations of sulphadiazine (SDZ) and trimethoprim (TMP) (cotrimazine) and tablets with sulphamethoxazole (SMZ) and TMP (co-trimoxazole) were compared in patients with different renal functions. In normal renal function, SMZ is more similar to TMP than in renal impairment. In renal impairment although the serum half-life (t1/2) of both active and total SDZ remains similar to that of TMP, the t1/2 of total SMZ becomes several times higher than the t1/2 of TMP. The unchanged SMZ maintains approximately the same elimination velocity in reduced as in normal renal function. Consequently, for co-trimoxazole there is a buildup of SMZ metabolites which can only contribute to toxicity for co-trimoxazole, whereas the co-trimazine components have t1/2 values of the same order, also in renal dysfunction. The distribution volumes of SDZ, SMZ or TMP are the same regardless of renal function. However, the distribution volume of SDZ is closer to that of TMP, i.e. higher than the SMZ values. More active SDZ is excreted in the urine than SMZ both in normal and in reduced renal function. Thus co-trimazine, in addition to having some advantages in the normal individual, is in many respects distinctly more suitable in patients with renal functional impairment. On the basis of the patients with renal functional impairment. On the basis of the pharmacokinetic properties, dosage schedules are suggested that will give approximately the same plasma levels regardless of renal function.
Low trimethoprim susceptibility of anaerobic bacteria due to insensitive dihydrofolate reductases.
All the 28 Bacteroides fragilis strains investigated were susceptible to sulfamethoxazole (minimal inhibitory concentration < 16 mug/ml) and resistant to trimethoprim (TMP; minimal inhibitory concentration > 4 mug/ml). Synergism between sulfamethoxazole and TMP was present in all strains at a ratio of 1:1. The few clostridia investigated proved more resistant to both compounds. Dihydrofolate reductases from B. fragilis, C. perfringens, and some other anaerobic species were isolated. Inhibition profiles with six structurally different inhibitors revealed major differences in all enzymes. For 50% inhibition, the enzyme from B. fragilis and all clostridia required concentrations of TMP which were between several hundredfold and 1,000-fold higher than those required for the enzyme of Escherichia coli, whereas the enzyme from Propionibacterium acnes only needed a threefold higher concentration. In vitro activities of TMP were seen to correspond to the activity at the enzymatic level in B. fragilis and P. acnes, but correspond to a much lesser extent to the activity at the enzymatic level in clostridia, where a poor penetration is assumed to be involved. Dihydrofolate reductase inhibitors other than TMP were found to be as active as TMP both at the enzyme and in vitro. In B. fragilis, higher concentrations of exogenous thymidine were required for increasing the minimal inhibitory concentration of TMP than in E. coli and probably also in C. perfringens.
Rifampin plus trimethoprim: bactericidal activity and suppression of resistance in human urine in vitro.
The bactericidal effect of a combination of rifampin (Ramp) and trimethoprim (Tmp) was studied using dense cultures of test organisms, including some urinary pathogens, growing in human urine. Drug concentrations used were similar to those attainable in human urine. The combination was more effective than the individual drugs and than a combination of Tmp plus sulfamethoxazole (Smx). Tmp was bactericidal in urine and blocked the emergence of Ramp-resistant bacteria. Ramp was responsible for most of the bactericidal action of the combination but also potentiated the bactericidal activity of Tmp. Ramp suppressed the selection of thy- (Tmp-resistant) bacteria. Under the experimental conditions, Smx+Tmp was not more bactericidal than Tmp alone for most of the test organisms, despite strong synergy between the two at subinhibitory concentrations.
Kinetics and mechanisms of action of 'folate synthesis inhibitors', alone or in combination, on Escherichia coli. III. Pyrimethamine, trimethoprim and sulfamethoxazole.
The inhibitory activity of pyrimethamine (PMA) is 1/290 of the activity of trimethoprim (TMP) against E. coli as evaluated from a plot of C.ko/ko-kapp VS. C. Even at high concentrations the effect of PMA in contrast to TMP seems to be cateriostatic. Combinations of TMP and PMA reveal an additive effect. In PMA-treated cultures, the slope of the logarithmic growth curve decreases after an initial inhibited growth, and a second steady state is established. This second steady state has a different reason than the one observed in TMP-treated cultures; whereas the second phase in TMP-inhibited cultures depends on the number of germs, in the case of PMA it depends on the number of generations. Using prewashed cell cultures, it was shown that there is no influence on the two steady states in PMA-inhibited cultures; for TMP, however, it was shown that the presence of the first phase is due to an antagonist excreted into the culture medium. These observations hint at differences in the mode of action of TMP and PMA in addition to differences in the affinity to the target enzyme dihydrofolate reductase. Combination of PMA with sulfamethoxazole (SMZ) at concentrations where both drugs are acting only bacteriostatically leads to effects considerably greater than would be expected from simple additivity. The kill rate observed is the same as observed for TMP/SMZ combinations despite of the considerable lower activity of PMA and SMZ. The results support the assumption that it might be possible to select drug combinations considering the best pharmacokinetical fit and not necessarily the most effective drugs in the series studied.
In vitro additive effect of nitrofurantoin combined with trimethoprim-sulfamethoxazole against Serratia marcescens.
The combination of nitrofurantoin (NF) plus trimethoprim-sulfamethoxazole (TMP-SMZ) was found to be additively effective against all of 12 clinical isolates of Serratia marcescens that represented 7 nosocomially significant strains, some of which were mulitple-drug-resistant. All isolates were resistant against NF; minimal inhibitory concentrations (MICs) ranged from 320 to 1,280 microgram NF/ml. The isolates were inhibited by TMP-SMZ concentrations ranging from 0.03 microgram TMP + 0.57 microgram SMZ/ml to 8 microgram TMP + 152 microgram SMZ/ml. Significantly, NF combined with TMP-SMZ proved effective against isolates with decreased susceptibility to TMP-SMZ as well. The observed in vitro additive effect of NF + TMP-SMZ might prove of clinical relevance with respect to the chemotherapy of hospital-acquired urinary tract infections due to multiple-drug-resistant strains of S. marcescens.
[Trimethoprim resistance plasmids: transferability and incompatibility groups (author's transl)].
Over a three year period, 119 strains of enterobacteria isolated from patients have been found resistant to trimethoprim (TMP) and sulfonamides (Su); 11 strains were resistant to TMP only. MIC of TMP were between 32 and 2048 microng/ml. Three groups of strains are described: (1) thymineless variants (2 strains); (2) TMP resistance non-transferable into Escherichia coli K12 (95 strains); (3) TMP resistance transferable into E. coli K12 (33 strains). TMP marker and Su marker have been transferred independantly from 13 strains; they were cotransferred from 20 strains. The incompatibility group of 31 plasmids has been determined: 10 belong to the fi+ type, group FII; 21 belong to the fi--type, group 6, group 7, group 10, group N and group I1. Epidemiological implications of such a wide range of incompatibility groups among a small number of plasmids specifying TMP resistance are discussed.
Intravenous trimethoprim-sulfamethoxazole in the treatment of serious infections in children.
Intravenous TMP-SMZ was used to treat 19 infectious episodes in 18 patients ranging in age from 3 weeks to 13 years. Thirteen patients with various soft tissue or skeletal infections caused by Haemophilus influenzae, Streptococcus pneumoniae, Staphylococcus aureus. Streptococcus pyogenes, or Acinetobacter anitratus were successfully treated. Three children with four episodes of CSF shunt infections due to coagulase-negative staphylococci were treated successfully also. The only treatment failures were in two newborn infants with enteric gram-negative bacterial ventriculitis. TMP-SMZ was given at a daily dose of 10 and 50 mg/kg, respectively, every six hours. The drug was administered intravenously for a mean duration of 10 days (range 4 to 32); in 11 patients this was followed by oral administration for a mean of nine days (range 2 to 18). Half-life of TMP after intravenous administration was 5 1/4 hours; that of SMA was 8 1/2 hours. Levels determined three to four days after starting therapy were generally higher than levels obtained at corresponding times after the first dose. CSF/blood TMP and SMA ratios, determined in four patients, were 0.6 and 0.5, respectively. Side effects were observed in 14 patients, and neutropenia was the most common adverse reaction. Intravenous TMP-SMZ is an effective antimicrobic agent in the treatment of infections due to susceptible organisms. The frequent side effects, although reversible and of no major clinical consequence, suggest that future use of TMP-SMZ should be monitored closely.
Clinical pharmacology of intravenously administered trimethoprim-sulfamethoxazole.
Pharmacokinetic studies of intravenously administered trimethoprim-sulfamethoxazole (TMP-SMX) were conducted in 11 patients with cancer while they received therapy with this drug combination for infection. Each patient received 160 mg of TMP and 800 mg of SMX every 8 h. The highest plasma concentrations of both agents were attained at the end of a 1-h infusion period, and the levels were maintained above 38 mug of free SMX and 2 mug of TMP per ml for 2 to 4 h on day 1. On day 4, these concentrations were exceeded at all time intervals of blood sampling. High concentrations of TMP and free SMX were recovered in the urine during the 8-h period. The plasma half-lives of TMP and free SMX, as determined during the first 8-h period, were 7.6 and 8.6 h, respectively. Compared with SMX, TMP had an approximately 2.5 times higher volume of distribution. This drug combination was well tolerated by the patients and unaccompanied by drug-related toxicity.