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Allopurinol for chronic prostatitis.

OBJECTIVES: To determine the effects of allopurinol in the treatment of chronic prostatitis SEARCH STRATEGY: Trials were searched in computerized general and specialized databases (MEDLINE, Cochrane Library, Cochrane Prostate Group database), bibliographies of obtained articles, and direct contact with authors. SELECTION CRITERIA: All randomized trials of allopurinol versus placebo used to treat patients with chronic prostatitis. Acute prostatitis, bacterial prostatitis, and asymptomatic prostatitis were excluded. The main outcome measure was the change in patient-reported discomfort. DATA COLLECTION AND ANALYSIS: The reviewers extracted the data independently for the outcomes of change in patient-reported discomfort, investigator graded prostate pain, leukocyte counts, and biochemical indices. MAIN RESULTS: Only one trial with 54 men lasting 240 days (with 330 days of follow-up) met study inclusion criteria. There was a statistically significant change favoring allopurinol in patient-reported discomfort between the study and control groups at follow-up. Between days 45-225, the mean score was -0.95 (s.d. 0.19) for the allopurinol group (7 men), compared with -0.47 (s.d. 0.21) for the placebo group (7 men). The weighted mean difference (WMD) was -0.48 (95%CI -0.690, -0.270). The mean score between days 45-135 was -1.08 (s.d. 1.29) for the 25 men in the allopurinol group, compared with -0.21 (sd 0.97) for the 14 men in the control group. The WMD was -0.87 (95%CI -1.587, -0.153). The allopurinol group had significantly less investigator graded prostate pain and had lower levels of serum urate, urine urate, and expressed prostatic secretion urate and xanthine. No significant differences between the two groups regarding leukocyte counts were found. No patient receiving allopurinol had any significant side effects. Three patients in the placebo group dropped out because of side effects. REVIEWER'S CONCLUSIONS: One small trial of allopurinol for treating chronic prostatitis showed improvements in patient-reported symptom improvement, investigator-graded prostate pain, and biochemical parameters. However, the data provided, the measures used, and the statistics presented do not make these findings convincing that changes in urine and prostatic secretion composition regarding purine and pyrimidine bases resulted in the relief of symptoms. Further studies of allopurinol treatment using standardized and validated outcomes measures and analyses are necessary to determine whether allopurinol is effective.

Allopurinol↗

The optimal use of allopurinol: an audit of allopurinol use in South Auckland.

BACKGROUND: Gout is a common and challenging problem in South Auckland, New Zealand. Allopurinol is widely used but urate reduction remains unsatisfactory. Allopurinol dosing guidelines and a therapeutic range for plasma oxypurinol levels have been published. AIMS: We aimed to determine the appropriateness of allopurinol dosing according to current guidelines and to assess the relationship between plasma creatinine, oxypurinol and urate. In addition, we assessed the clinical usefulness of the oxypurinol level. METHODS: Thirty-one patients, on a stable dose of allopurinol for at least three weeks, had plasma creatinine, urate and oxypurinol measured as part of routine clinical assessment. Relationships between the various methods were examined using regression analysis. Fisher's exact test was used to test associations with categorical variables. RESULTS: Fifty-five per cent of patients were on higher than recommended doses of allopurinol. There was a statistically significant relationship between calculated creatinine clearance and plasma oxypurinol level. Only 50% of patients with a plasma oxypurinol within the therapeutic range (30-100 micromol/L) had a plasma urate < 0.42 mmol/L and this did not increase significantly in the patients with an oxypurinol level > 100 micromol/L. CONCLUSIONS: There is poor adherence to the current recommended dosing guidelines for allopurinol. Creatinine clearance rather than plasma creatinine needs to be used to predict the dose of allopurinol. The current role of the oxypurinol level is to identify non-compliers with allopurinol therapy. We need further research to clarify whether increasing the dose of allopurinol outside the recommended dose range to reach an oxypurinol level of close to 100 micromol/L may be of benefit in those who have not had sufficient urate reduction.

Adult↗

Combination allopurinol and antimony treatment versus antimony alone and allopurinol alone in the treatment of canine leishmaniasis (96 cases).

The aim of the present study was to evaluate the long-term clinical outcome for dogs with leishmaniasis that were treated with 3 different protocols: combined treatment with antimony and allopurinol, antimony alone, or allopurinol alone. Ninety-six dogs included in this study were determined to have leishmaniasis on the basis of (1) clinical features, (2) identification of the parasite in smears of lymph node, bone marrow aspirates, or skin biopsies, and (3) specific immunofluorescent assay. Three groups of dogs were defined: 45 dogs (group 1) were treated with antimony (100 mg/kg s.c. q24h) given concurrently for 1 month with allopurinol (15 mg/kg p.o. q12h), and then allopurinol alone for 8 months at the same dosage; 40 dogs (group 2) were treated with antimony alone according to the manufacturer's instructions (200 mg/kg s.c. q24h at 2-day intervals for 3-6 months); and 11 dogs (group 3) were treated with allopurinol alone (15 mg/kg p.o. q12h for 1-20 months). Information concerning signalment, history, physical examination findings, serologic testing and number of dogs becoming seronegative, outcome for each treated dog (clinical cure versus failure), and long-term survival were recorded. The numbers of the clinical cures versus failures were significantly different among the 3 groups (chi2 = 17.77, P < .001), between groups 1 and 2 (chi2 = 8.02, P < .01), between groups 2 and 3 (chi2 = 11.00, P < .01), and between groups 1 and 3 (chi2 = 16.52, P < .001). No significant difference between groups 1 and 2 was noted in the type of failure (relapse or death), serologic test results, and number of survival years (chi2 = 2.79, P > .05). The results of the present study indicate that antimony in combination with allopurinol produces better results than antimony alone or allopurinol alone for the treatment of the canine leishmaniasis. With combination treatment, duration of treatment with antimony is shorter and long-term administration of allopurinol is well tolerated.

Allopurinol↗

On the metabolism of allopurinol. Formation of allopurinol-1-riboside in purine nucleoside phosphorylase deficiency.

Allopurinol-1-riboside, a major metabolite of allopurinol, is commonly thought to be directly synthesized by purine nucleoside phosphorylase (PNP) in vivo. As this enzyme is otherwise believed to function in vivo primarily in the direction of nucleoside breakdown, we have determined by high performance liquid chromatography and a conventional chromatographic method the urinary metabolites of allopurinol in a child deficient of PNP. In this patient approximately 40% of urinary allopurinol metabolites consisted of allopurinol-1-riboside, thus proving the possibility of indirect formation of allopurinol-1-riboside via allopurinol-1-ribotide in vivo, catalysed by hypoxanthine guanine phosphoribosyltransferase (HGPRT) and a phosphatase.

Allopurinol↗

Effect of BOF-4272 on the oxidation of allopurinol and pyrazinamide in vivo. Is xanthine dehydrogenase or aldehyde oxidase more important in oxidizing both allopurinol and pyrazinamide?

Allopurinol or pyrazinamide was administered to rats treated with BOF-4272 (a potent xanthine oxidase inhibitor) to investigate to what degree xanthine dehydrogenase participates in the oxidation of these agents. BOF-4272 markedly decreased the plasma concentration and the urinary excretion of both oxypurinol and 5-hydroxypyrazinamide. It also decreased the sum of the urinary excretion of allopurinol and oxypurinol and that of pyrazinamide and its metabolites, although it did not affect the sum of the plasma concentrations of allopurinol and oxypurinol at 105 min after administration of allopurinol or the plasma concentration of pyrazinamide during the period after the administration of pyrazinamide. These results suggested that BOF-4272 almost completely inhibited the oxidation of allopurinol and pyrazinamide and had some effect on the excretion and/or the tissue incorporation of these two compounds. Since the in vitro study demonstrated that BOF-4272 did not inhibit the activity of aldehyde oxidase, which oxidized both allopurinol to oxypurinol and pyrazinamide to 5-hydroxypyrazinamide, the results suggested that xanthine dehydrogenase was the more important enzyme in converting allopurinol to oxypurinol and pyrazinamide to 5-hydroxypyrazinamide.

Aldehyde Oxidase↗

Correction of allopurinol dosing should be based on clearance of creatinine, but not plasma creatinine levels: another insight to allopurinol-related toxicity.

BACKGROUND: Dosing of allopurinol should be corrected depending on renal function, but corrections based on either plasma creatinine (Pcr) or creatinine clearance (CrCl) have been suggested to be minimal standards of care. METHODS: Data from a cohort database of 484 gouty patients were used to calculate estimated allopurinol doses using CrCl and estimation of the clearance of creatinine using the equation of Cockroft and Gault (CrCl-CG) if, as a hypothesis, a dosage of 300 mg/d would be prescribed in any patient with Pcr <2.0 mg/dL. Also, allopurinol-related toxicity previous to rheumatologic consultation, during previous allopurinol therapy, and the relationship between both and estimated allopurinol doses were reviewed. RESULTS: The cutoff point of plasma creatinine <2 showed 13% sensitivity and 100% specificity to detect CrCl <50 mL/min. Correlation and agreement between CrCl and CrCl-CG were good, as was the correlation between corrected doses using CrCl and CrCl-CG. One third of patients with Pcr 1.0-1.5 mg/dL and 90% of those with Pcr 1.5-2.0 mg/dL would receive estimated doses over 400 mg/dL/d CrCl. Also, 10% and 34% would receive estimated doses over 600 mg/dL/d CrCl, respectively. Allopurinol-related toxicity previous to consultation (11%) was associated with estimated doses over 400 mg/dL/d CrCl and severe toxicity with estimated doses over 600 mg/dL/d CrCl. When patients were given doses corrected on CrCl, few side effects were observed during follow up (6.7%), and the only severe one was associated with corrected dose over 600 mg/d. CONCLUSIONS: Dosage adjustment of allopurinol should be based on clearance of creatinine or estimation of glomerular filtration using the Cockcroft-Gault equation. Pcr is insensitive enough to detect renal function impairment so that patients may be placed at risk for overdosing side effects. Corrected doses over 600 mg/dL/d CrCl may be associated with increased risk of severe toxicity.

Allopurinol↗

On the specificity of allopurinol and oxypurinol as inhibitors of xanthine oxidase. A pulse radiolysis determination of rate constants for reaction of allopurinol and oxypurinol with hydroxyl radicals.

Allopurinol has been employed as a "specific" inhibitor of xanthine oxidase in studies of hypoxic/reoxygenation injury. Pulse radiolysis was used to establish rate constants for the reactions of allopurinol and its major metabolite oxypurinol with hydroxyl radicals: values were (1.45 +/- 0.24) x 10(9) M-1 s-1 for allopurinol and (4.95 +/- 0.84) x 10(9) M-1 s-1 for oxypurinol. These rate constants show that, in view of the amounts of allopurinol that have been used in animal studies, hydroxyl radical scavenging by this molecule could contribute to its biological actions, especially if animals are pre-treated with allopurinol, so allowing oxypurinol to form. The ability of allopurinol to protect tissues not containing xanthine oxidase against reoxygenation injury may be related to radical scavenging by allopurinol and oxypurinol.

Allopurinol↗

The efficacy of combined low dose of Allopurinol and benzbromarone compared to standard dose of Allopurinol in hyperuricemia.

OBJECTIVE: To compare the efficacy of combined low dose of hypouricemic drugs (Allopurinol 100 mg and benzbromarone 20 mg; Allomaron) and standard dose 300 mg of allopurinol in hyperuricemia. MATERIAL AND METHOD: A prospective, open study of 94 hyperuricemic patients was done at King Chulalongkorn Memorial Hospital. Each group of 47 patients was given a combined low dose of hypouricemic drugs (Allopurinol 100 mg and benzbromarone 20 mg; Allomaron) and a standard dose 300 mg of allopurinol. Serum uric acid was measured before and 4 weeks after receiving the drugs. The efficacy was measured from the difference of the level of serum uric acid before and after receiving the drugs. RESULTS: The patients receiving the combined low dose of hypouricemic drugs and standard dose of allopurinol showed a mean reduction of serum uric acid of 2.5+/-3.4 mg/dl and 4.1+/-2.7 mg/dl consecutively. There was a statistically significant difference between the 2 groups (P = 0.010). CONCLUSION: This study demonstrates that the efficacy of standard dose 300 mg of allopurinol is superior to a combined low dose of allopurinol and benzbromarone in lowering the level of serum uric acid level.

Allopurinol↗

Allopurinol hypersensitivity syndrome: hypersensitivity to oxypurinol but not allopurinol.

Allopurinol is a xanthine oxidase inhibitor widely used to control plasma uric acid levels. Episodes of hypersensitivity to the drug are not rare. A severe form of this with a generalized exanthem, fever and liver involvement has been termed the allopurinol hypersensitivity syndrome (AHS). Patch testing and lymphocyte stimulation testing (LST) are not helpful in confirming this sensitivity. Allopurinol works as a substrate of xanthine oxidase, and is rapidly oxidized into oxypurinol in vivo. Therefore, the biological half-life of oxypurinol is markedly longer than that of allopurinol. In addition, conspicuous pre-existing renal impairment has been noted in many AHS patients. Thus, it is possible that AHS is a manifestation of hypersensitivity to oxy-, not allopurinol. Here, we now report three cases of AHS in which there were significant lymphoproliferative reactions to oxypurinol but not allopurinol.

Adult↗

Interaction of allopurinol and hydrochlorothiazide during prolonged oral administration of both drugs in normal subjects. II. Kinetics of allopurinol, oxipurinol, and hydrochlorothiazide.

The kinetics of allopurinol and hydrochlorothiazide were investigated in seven healthy male subjects during prolonged coadministration of two drugs. Subjects were maintained on an isoenergetic, purine-free formula diet with RNA supplementation for 24 days. Allopurinol (300 mg) was given orally on days 1-24. Hydrochlorothiazide (50 mg daily) was added to days 11-21. On day 43 a single oral dose of 50 mg hydrochlorothiazide was administered. Plasma concentration-time profiles of allopurinol and its main metabolite oxipurinol were obtained on days 1, 10, and 21; hydrochlorothiazide profiles were assessed on days 21 and 43. In addition, 24-h plasma concentrations of oxipurinol were measured repetitively, and 24 h urine samples were collected for the determination of allopurinol, oxipurinol, and hydrochlorothiazide. For oxipurinol, mean Cmax was not altered on hydrochlorothiazide treatment (13.8 +/- 1.4 micrograms/ml and 14.7 +/- 2.6 micrograms/ml, respectively); mean AUC0-24 was 259 and 290 micrograms h-1 ml-1, respectively. The small difference in AUC0-24 values does not explain the increase in plasma uric acid concentration during hydrochlorothiazide treatment, nor do the variations in allopurinol and hydrochlorothiazide kinetics.

Administration, Oral↗

Anti-leishmanial effect of allopurinol ribonucleoside and the related compounds, allopurinol, thiopurinol, thiopurinol ribonucleoside, and of formycin B, sinefungin and the lepidine WR6026.

Allopurinol and allopurinol ribonucleoside tested in vitro and in vivo for activity against Leishmania donovani. Activity in vitro was low against the amastigote form of this parasite with ED50 values of the order of 54 and 96 microM and 86 and 213 microM respectively for the two compounds. In vivo inhibition of up to 47% was achieved with allopurinol ribonucleoside given in the drinking water. However, low blood levels were found in the mouse relative to those in man. Low in vivo activity was also seen with allopurinol ribonucleoside against L. major and other species of Leishmania causing cutaneous lesions. The metabolism of allopurinol ribonucleoside in aldehyde oxidase deficient mice (inbred strains DBA/1, DBA/2) resembled that of man, but the antileishmanial activity remained low. Other compounds, formycin B, sinefungin and the lepidine WR6026 were highly active against mice infected with L. donovani or L. major.

Adenosine↗

Kinetics of allopurinol and its metabolite oxypurinol after oral administration of allopurinol alone or associated with benzbromarone in man. Simultaneous assay of hypoxanthine and xanthine by gas chromatography-mass spectrometry.

Allopurinol, oxypurinol, hypoxanthine and xanthine were assayed simultaneously using a highly specific method combining gas chromatography and mass spectrometry. Two hypo-uricaemic prescriptions were compared: i) 300 mg of allopurinol (AL); and ii) 100 mg of allopurinol plus 20 mg of benzbromarone (AL + BZB). When administered acutely, their effects on blood uric acid levels were similar. Analysis of the pharmacokinetic parameters of allopurinol and its metabolite after each treatment showed dose-linearity for the metabolite but not for the drug itself. The area under the concentration time curve for allopurinol was 40.3 +/- 9.3 mumol l-1 h after AL, against 8.4 +/- 3.9 mumol-1 h after AL + BZB, while for oxypurinol it was 948.0 +/- 125.4 mumol l-1 h after AL and 285.2 +/- 77.9 mumol l-1 h after AL + BZB. The difference in dosage form may partly account for this difference, but the benzbromarone also seems to be involved. Its role on the blood uric acid lowering action of the drug association is complex. Although benzbromarone appreciably favors the elimination of oxypurinol, which should result in a weakening of its hypo-uricaemic action, this is offset by enhanced elimination of hypoxanthine and xanthine. Renal clearance of xanthine was significantly increased under AL + BZB (173.1 +/- 65.6 ml/min against 112.2 +/- 32.9 ml/min after AL). Similarly, blood xanthine levels were proportionately higher in the presence of benzbromarone. The action of the two agents may thus be synergistic and not antagonistic, a pharmacological justification for the therapeutic use of this drug association.

Adult↗

[The clinical pharmacokinetics of allopurinol. 1. Allopurinol absorption sites and dose proportionality of allopurinol/oxipurinol bioavailability].

The rate and extent of allopurinol absorption was studied following its oral ingestion in a "high frequency capsule" which allows the evaluation of the sites of drug absorption. If allopurinol is liberated in the duodenum or upper jejunum its absorption is fast and complete while its liberation in the lower jejunum results in a slow and incomplete absorption. A capacity limited absorption process for allopurinol, suggested from the results of a study on the allopurinol bioavailability from different formulations, could not be proved in the range of single doses between 200 and 600 mg resp. 2.2 to 12.8 mg/kg. AUC- and Cp-values of allopurinol and oxipurinol correspond to the calculated figures in relation to the different doses/kg.

Adult↗

Moment analysis of hepatic local disposition of allopurinol and oxipurinol: metabolism kinetics from allopurinol to oxipurinol in the rat isolated perfused liver.

Drug metabolism in the liver was examined by the rat isolated perfused liver using the single-pass bolus-input technique. The test compounds, allopurinol and its metabolite oxipurinol, were independently introduced into the liver from the portal vein, and the concentration profiles in the venous outflow were monitored and kinetically analysed by moment theory. The recovery ratios of allopurinol and oxipurinol after the individual administration of each drug were estimated to be 0.17 (+/- 0.08 s.d.) and 1.03 (+/- 0.02 s.d.), respectively. The outflow recovery ratio of oxipurinol as the metabolite after allopurinol administration was estimated to be 0.80 (+/- 0.07 s.d.). These results indicate that the combined outflow recovery of the precursor and the metabolite after allopurinol administration is almost 100% in the rat liver.

Allopurinol↗

Phenytoin--allopurinol interaction: Michaelis--Menten kinetic parameters of phenytoin with and without allopurinol in a child with Lesch--Nyhan syndrome.

We analyzed Michaelis--Menten pharmacokinetic parameters of phenytoin with and without the coadministration of allopurinol (150 and 200 mg/day) in a child with Lesch--Nyhan syndrome. The Vmax and Km were estimated from at least two different sets of serum concentration--dosage data of phenytoin. The Vmax values (mg/kg/day) were 16.1 without allopurinol, and 12.4 and 10.9 with allopurinol (150 and 200 mg/day), respectively, whereas those for Km remained relatively constant (3.9 to 4.9 microgram/ml). Our results suggest that allopurinol is a drug that inhibits the hepatic metabolism of phenytoin.

Adolescent↗

Antileishmanial effect of allopurinol. II. Relationship of adenine metabolism in Leishmania species to the action of allopurinol.

Allopurinol was shown to be effective in vitro against Leishmania mexicana and Leishmania donovani as well as against Leishmania braziliensis. The major metabolic derivative of allopurinol in humans, oxipurinol, also is antileishmanial for L. donovani. The antileishmanial effect of allopurinol and oxipurinol can be specifically reversed by adenine, and its metabolic precursors and derivatives, but by no other purines or their derivative. It is proposed that the adenylosuccinate synthetase or the adenine phosphoribosyltransferase may be sites of action for these agents.

Adenine↗

Allopurinol kinetics in humans as a means to assess liver function: evaluation of an allopurinol loading test.

A newly developed liver function test was performed on 18 apparently healthy individuals and 29 patients with liver disease. After intravenous injection of a low dose allopurinol (17.1 mumol/kg body mass), blood specimens were collected during 1 h. Plasma analyses of allopurinol and its metabolite oxipurinol were performed and the data were processed by means of a computer-based biodynamic model. This modelling approach makes it possible to estimate parameters, containing information about liver perfusion, hepatocyte membrane transport and hepatocyte cell mass. One parameter (kA31) showed complete discrimination between the reference sample group of healthy individuals and patients with severe liver dysfunction. In a reference sample group of patients with slightly to moderately reduced liver function, only a few patients (5/20) had a kA31 value over the decision limit. In this respect, the allopurinol loading test is superior to the conventional intravenous galactose tolerance test.

Adolescent↗

[Clinical pharmacokinetics of allopurinol. 3. Allopurinol/oxipurinol pharmacokinetics following administration of a controlled release allopurinol preparation].

Studies of the Clinical Pharmacokinetics of Allopurinol/3rd Communication: Allopurinol/oxipurinol bioavailability and pharmacokinetics following the administration of a controlled release allopurinol formulation. Regarding the results of our studies on the localization of the absorption of allopurinol and the kinetic behavior of allopurinol/oxipurinol following multiple administration the bioavailability and kinetic properties of the drug delivered from controlled release tablets were studied in healthy volunteers. Allopurinol controlled release tablets (Sigapurol CR), containing 200 mg of the drug characterized by rapid absorption and 100 mg characterized by pH-dependent delivery, were identified as a formulation with advantages pharmacokinetic properties.

Adult↗