Successful desensitization to dapsone for Pneumocystis carinii prophylaxis in an HIV-positive patient

OBJECTIVE: To report a case of successful desensitization to dapsone for Pneumocystis carinii pneumonia (PCP) prophylaxis in a patient unable to tolerate trimethoprim/sulfamethoxazole (TMP/SMX) desensitization or dapsone at standard doses. CASE SUMMARY: A 37-year-old HIV-positive African-American man was treated for pneumonia with TMP/SMX and then continued on the drug for PCP prophylaxis. After experiencing a pruritic maculopapular rash with TMP/SMX, both at standard doses and after attempting a desensitization regimen to the drug, he was started on dapsone for PCP prophylaxis. He experienced a rash and fever after taking dapsone at standard PCP prophylactic doses. At this time, an 18-day oral dapsone rechallenge by dose escalation was attempted, and it was well tolerated. CONCLUSIONS: This case suggests that utilization of a dapsone desensitization regimen may permit a viable treatment option in patients previously thought to be intolerant to the agent. More regimens of this type should be attempted and the results published, using both dapsone and TMP/SMX, so that standard desensitization treatment guidelines may eventually be adopted.     

13th report on the structure and performance statistics of heart catheterization laboratories in Germany

Children who undergo bone marrow transplantation (BMT) are at risk for Pneumocystis carinii pneumonia (PCP). Prophylaxis using trimethoprim/sulfamethoxazole (TMP/SMX) is highly effective but the incidence of adverse drug reactions is significant. We retrospectively reviewed 33 pediatric BMT (25 allogeneic and eight autologous) in whom dapsone was used for PCP prophylaxis because patients were unable to receive TMP/SMX. Dapsone was administered at 50 mg/m2 p.o. once a week from engraftment to 180 days post-autologous BMT, and to 1 year or throughout the duration of immunosuppressive treatment post-allogeneic BMT. With a total of 7268 patient days of dapsone prophylaxis and a median follow-up of 353 days post-BMT, no proven PCP was diagnosed. Sixteen cases of chest radiograph abnormalities were noted in this patient population but none was attributed to PCP. Dapsone was well tolerated by all children with no serious adverse effects; however, one patient developed Toxoplasma gondii encephalitis during dapsone prophylaxis. Dapsone warrants further evaluation as an alternative for PCP prophylaxis in pediatric BMT patients intolerant of TMP/SMX. Additional prophylaxis should be considered for patients at high risk for T. gondii encephalitis.     

Simultaneous pancreatitis and hepatitis associated with trimethoprim-sulfamethoxazole

A 34-yr-old woman developed simultaneous pancreatitis and hepatitis following exposure to trimethoprim-sulfamethoxazole (TMP/SMX). The episode occurred 4 yr after a previous episode of hepatitis associated with TMP/SMX. This patient represents the second case of concurrent TMP/SMX-induced pancreatitis and hepatitis reported in the literature. However, it is the first in which the adverse reaction was documented following an inadvertent rechallenge with the drug.     

Adverse reactions to fluconazole: illustrative case with focus on desensitization

Fluconazole is an azole antifungal agent. Because it can be taken orally, it is preferred over amphotericin B for long-term treatment. Indications for fluconazole are increasing. Reports of hypersensitivity have been described. If adequate alternative therapy is not available, desensitization may be necessary. Desensitization with fluconazole has not been described. The patient described in this report required fluconazole and was successfully desensitized after manifesting a type 1 hypersensitivity reaction. The patient underwent desensitization during a 15-day period. The starting dose was less than 0.001 dose, with doubling each day. During desensitization, the patient experienced a slight transient rash that resolved with continued therapy. After desensitization, he has continued using fluconazole daily without adverse effects. This report indicates that desensitization to fluconazole can be accomplished safely in selected patients. A suggested desensitization protocol is provided.     

Regression-line analysis of trimethoprim-sulfamethoxazole activity against Neisseria gonorrhoeae

A standardized disk diffusion test was developed and used to test the susceptibility of 102 strains of Neisseria gonorrhoeae to combinations of trimethoprim and sulfamethoxazole (TMP/SMX) by relating zone diameters of inhibition to minimal inhibitory concentrations (MIC's). MIC's for TMP/SMX in ratios of 1:20 ranged from 0.08/1.52 to 2.5/47.5 mug/ml and zones of inhibition ranged from 34 to 10 mm. The coefficient of correlation (r) was -0.75. For comparison, a regression line was similarly calculated for ampicillin. MIC's ranged from 0.02 to 0.32 mug/ml and zones of inhibition ranged from 50 to 31 mm; r was -0.71. With establishment of MIC breakpoints to define the categories, susceptible, intermediate, and resistant, the disk duffusion test would be as reliable for estimating susceptibility of gonococci to TMP/SMX as for estimating susceptiblity to ampicillin.     

Rifaximin: a nonabsorbed antimicrobial in the therapy of travelers' diarrhea

BACKGROUND/AIMS: Bacterial enteropathogens, the major cause of travelers' diarrhea, are customarily treated with antibacterial drugs. Rifaximin, a nonabsorbed antimicrobial was examined as treatment for travelers' diarrhea. METHODS: A randomized, prospective, double-blind clinical trial was carried out in 72 US adults in Mexico. Patients with acute diarrhea received one of three doses of rifaximin (200, 400 and 600 mg t.i.d.) or trimethoprim/sulfamethoxazole (TMP/SMX, 160 mg/800 mg b.i.d.) for 5 days. Results were compared with data from 2 placebo-treated historical control populations. RESULTS: The shortest duration of treated diarrhea was seen in the group receiving 200 mg rifaximin t. i.d (NS). Clinical failure to respond to treatment occurred in 6 of 55 (11%) rifaximin-treated subjects versus 5 of 17 (29%) of TMP/SMX-treated subjects (NS). Sixteen of twenty (80%) of the enteropathogens isolated from the rifaximin-treated subjects and 7 of 7 (100%) from the TMP/SMX group were eradicated by treatment (NS). Sixteen of twenty-four (67%) enteropathogens identified were susceptible to TMP and all 24 were inhibited by相似文献   

Incomplete aspirin desensitization in an aspirin-sensitive asthmatic

Aspirin desensitization is a valuable treatment for aspirin-sensitive sinusitis. We present a case where long-term desensitization failed. While undergoing desensitization, our patient had prolonged severe asthmatic reactions and therefore received high intravenous doses of prednisone. We hypothesize that high steroid doses administered at the time of desensitization may have raised the threshold of intolerance to a point where the administered aspirin doses were tolerated. Consequently, symptoms of intolerance subsided during the procedure. Subsequent tapering down of the daily prednisone dose caused a re-emergence of the symptoms of intolerance, apparently due to a decrease in the intolerance threshold.     

Discrimination between rival dosing histories

PURPOSE: In population pharmacokinetic studies, the dosing history is sometimes recorded in more than one way. The purpose of this study was to develop and evaluate a procedure for discriminating between rival dosing histories, i.e., for each individual in a data set, identify the dosing history that is the most plausible. METHODS: The procedure consists of four steps. In the first step we identify individuals whose dosing histories produce predictions that are consistent. In the second step these individuals are used to build a population pharmacokinetic model which is used, in step three, to select the dosing history for the individuals not identified in step one. In step four the population model is refined using the best available dosing histories for all individuals. The proposed procedure was evaluated using both simulations and a real data set, in which two dosing histories, based on patient diaries and electronic monitoring devices (MEMS) were available. RESULTS: In the real data set, estimated variabilities were almost always lower when the selected dosing histories were used compared to when no selection procedure was used. The diary dosing histories were selected more often than the MEMS dosing histories. In the simulations, the parameter estimates obtained using the selection procedure were closer to the true parameter values compared to when only one of the dosing histories was used. CONCLUSIONS: The proposed procedure appears to be robust and should be beneficial in at least two respects: improved parameter estimation of population pharmacokinetic and PK/PD models and objective information by which dosage recording methodologies can be compared and patient dose recording behavior can be assessed.     

MRI and articular cartilage

There are considerable laboratory data and information from animal and continuous culture in vitro models to support continuous infusion therapy for penicillins and cephalosporins, but, as yet, the only existing clinical data relate to cephalosporins. Penicillins do not exert concentration-dependent killing in the therapeutic range but have a post-antibiotic effect (PAE) against Gram-positive cocci but not Gram-negative rods. Animal models indicate the time (T) during which the serum concentrations exceed the minimum inhibitory concentration (MIC) of the pathogen [T > MIC] determines outcomes. Pharmacokinetic studies in humans indicate that continuous infusion with penicillins is possible but there are no clinical data on efficacy. Cephalosporins have similar pharmacodynamic properties to penicillins; T > MIC determines outcome. Data related to ceftazidime indicate that the drug concentration at steady-state (Css) should exceed the pathogen MIC by > 1-fold and perhaps by 4- to 5-fold or more. Human pharmacokinetics of ceftazidime administered by continuous infusion to a wide variety of patient groups indicates that Css of > 20 mg/L can easily be achieved using conventional daily doses. Clinical data indicate increased effectiveness of a continuous regimen in neutropenic patients with Gram-negative infection. Furthermore cefuroxime administration by continuous infusion has resulted in lower doses and shorter course durations. Little is known of the pharmacodynamics of monobactams and there are few clinical data on continuous infusion therapy. Carbapenems have different pharmacodynamics to other beta-lactams as they have concentration-dependent killing and a PAE with both Gram-positive and Gram-negative bacteria. While T > MIC has a role in determining outcomes, the proportion of the dosing interval for which serum drug concentrations should exceed the pathogen MIC is less than for other beta-lactams. In vitro models have shown that continuous infusion is effective, as is less frequent dosing. There are few data on continuous infusion of carbapenems but some patients have been treated with once-daily dosing. Clinically, continuous infusion therapy with penicillins and cephalosporins should be considered in patients infected with susceptible Gram-negative rods not responding to conventional therapy. As an approximation, the same total daily dose should be given but a bolus intravenous injection should be give at the start of continuous infusion to ensure Css is reached rapidly. The Css may be difficult to predict and determination of serum drug concentrations may be indicated. Ideally, the Css should be calculated based on the MIC of the potential pathogen and may be higher or lower than the Css achieved by a conventional daily dose.     

A method for uni-directional reconstitution of human erythrocyte glucose transporter

STUDY OBJECTIVE: To determine whether patient factors other than body weight would better predict patients' initial antifactor Xa heparin activity (HA) after start of unfractionated heparin (UFH) therapy. DESIGN: Case series. SETTING: A 625-bed, adults-only, private, tertiary care teaching hospital. PATIENTS: Ninety-two patients requiring UFH therapy. INTERVENTIONS: Patients received initial UFH bolus doses of 72-80 U/kg ideal weight and initial UFH infusions of 19.1-21.2 U/kg ideal weight. MEASUREMENTS AND MAIN RESULTS: Fifty-five percent of the first 6-hour HA measurements were supratherapeutic (> 0.7 U/ml antifactor Xa activity). Patient weight was inferior to a combination of age and estimated plasma volume in predicting initial HA. A predictive model including these two factors accounted for 38.5% of variation in first HA levels compared with 17.7% with actual weight alone. CONCLUSION: Weight-based UFH dosing may frequently result in nontherapeutic initial HA levels. Initial UFH dosing might be improved if protocols based on patient age and estimated plasma volume were developed.     

Evaluation of the efficacy and tolerability of a low-dose combination of isradipine and spirapril in the first-line treatment of mild to moderate essential hypertension

To investigate the concept of initiating therapy with low doses of a calcium antagonist and an ACE inhibitor, a fixed combination of isradipine 2.5 mg plus the ACE inhibitor spirapril 3 mg was compared with its components, with the full-dose monotherapies (isradipine 5 mg or spirapril 6 mg), and with placebo. After a 2-week wash out phase in pretreated patients and a subsequent 2-week placebo period, 405 patients with a diastolic blood pressure (DBP) between 100 and 114 mmHg were randomly allocated to 12-week once-daily double-blind treatment in one of the six treatment arms. In patients whose blood pressure was not normalized (defined as DBP< or =90 mmHg) after 6 weeks of treatment, the dosage of either medication was doubled or, in the placebo group, was switched to the fixed combination. After week 6, the mean reductions from baseline in sitting systolic/diastolic blood pressure 24 hours after dosing (trough) for the fixed combination or the monotherapies isradipine 5 mg, isradipine 2.5 mg, spirapril 6 mg, spirapril 3 mg, and placebo were 10.4/8.7, 10.0/9.4, 6.5/6.7, 10.0/8.3, 7.0/5.8, and 2.2/4.7 mmHg, respectively. The blood pressure changes obtained with the low-dose fixed combination were essentially identical to those observed with the full-dose monotherapies, thus showing an additive effect of low-dose isradipine and spirapril. In terms of tolerability, the lowest rate of any adverse events was found in the combination group. In this group, typical adverse events of calcium antagonists, such as headache, flushing, ankle edema, or palpitations, were observed only in 5%, 2%, 1%, and 0%, respectively, dry cough, considered typical for ACE inhibitors, was observed in only 1% of the combination group. In conclusion, the low-dose components isradipine 2.5 mg and spirapril 3 mg were shown to have an additive effect when combined, exerting a blood pressure-lowering effect comparable with the full doses and a trend to a better tolerability profile in comparison with the standard doses. Thus, low-dose combination therapy with these drugs appears to be a rational alternative to conventional monotherapy in the first-line treatment of hypertension.     

Fluoxetine tenth anniversary update: the progress continues

This tenth anniversary review/update of fluoxetine concentrates on the past 5 years of its clinical application. The mechanism of action of fluoxetine; its metabolism; its efficacy in patients with various diagnostic subgroups of depression, patients with coincident medical disease, children and adolescents with depression, patients with eating disorders, and patients with obsessive-compulsive disorder (OCD); its long-term (maintenance) efficacy; its side effects and toxicity; and pharmacoeconomic considerations are reviewed. Pharmacotherapy is currently the only proven method for treating major depressive disorder that is applicable to all levels of severity of major depressive illness. Since its introduction 10 years ago, fluoxetine has been available to psychiatrists, primary care physicians, and other nonpsychiatric physicians as full-dose effective pharmacotherapy for patients with depression. Fluoxetine has been widely prescribed by physicians knowledgeable in pharmacology and in the treatment of depression because of its proven efficacy (ie, equal to that of tricyclic antidepressants [TCAs]), its ease of administration (with full therapeutic dosing usually starting from day 1), its generally benign side-effect profile, its remarkable safety in over-dose, and its proven effectiveness in the most common depressed patient population--anxious, agitated, depressed patients--as well as in patients with various subtypes and severities of depression. In more recent years it has also proved effective in the treatment of bulimia, an entity for which only limited or inadequate treatment options had been previously available. In OCD, fluoxetine, with its more acceptable side-effect profile and greater ease of dosing, presents a favorable alternative to previous drug therapy and is useful in treating both obsessions and compulsions. Fluoxetine is currently recognized among clinicians as efficacious in treating anxiety disorders and is being used successfully in special depressed populations such as patients with medical comorbidity, elderly patients, adolescents, and children. Rapid discontinuation or missed doses of short-half-life selective serotonin reuptake inhibitors, TCAs, and heterocyclic antidepressants are associated with withdrawal symptoms of a somatic and psychological nature, which cannot only be disruptive, but can also be suggestive of relapse or recurrence of depression. In striking contrast to these short-half-life antidepressants, fluoxetine is rarely associated with such sequelae on sudden discontinuation or missed doses. This preventive effect against withdrawal symptoms on discontinuation of fluoxetine is attributed to the unique extended half-life of this antidepressant. Current studies show that the overall increased effectiveness of fluoxetine in treating depression compensates for its higher cost, compared with older drugs, by reducing the need for physician contact because of increased compliance and less need of titration, and by reducing premature patient discontinuation, thereby yielding fewer relapses, less recurrence, and less reutilization of mental health services.     

Trigeminal afferents and brainstem centers involved in the occurrence of cerebral vasospasm

OBJECTIVE: To study the outcome of a modified oral desensitization protocol for trimethoprim-sulfamethoxazole in human immunodeficiency virus infected patients with Pneumocystis carinii pneumonia and acquired immune deficiency syndrome. DESIGN: A prospective study. SETTING: Tertiary care referral center. PATIENTS: Thirteen human immunodeficiency virus infected patients with Pneumocystis carinii pneumonia and allergy to sulfonamides who failed alternative therapy. INTERVENTION: Oral desensitization to trimethoprim-sulfamethoxazole. MEASUREMENTS: Nature of allergic reactions, toxicity of alternate medications, indication as well as outcome of trimethoprim-sulfamethoxazole desensitization and routine laboratory determinations. RESULTS: The most common reaction to trimethoprim-sulfamethoxazole was generalized, pruritic maculopapular rash (n = 10, 76.9%) followed by urticaria/angioedema in two patients (15.38%). Two patients had generalized pruritus without rash. All patients (n = 13) tolerated oral desensitization to trimethoprim-sulfamethoxazole without any adverse reactions including three patients who were critically ill and on mechanical ventilation. Thus the success rate of our protocol was 100%. No patient had received antihistamines prior to or during the protocol. Four patients (5, 6, 7, and 9) were receiving prednisone for severe Pneumocystis carinii pneumonia. Total followup has ranged from 4 to 84 weeks. Two patients died during followup due to causes unrelated to desensitization. All other patients are tolerating trimethoprim-sulfamethoxazole without any allergic reactions. CONCLUSIONS: Oral desensitization to trimethoprim-sulfamethoxazole, as per this protocol is safe, in that there were no systemic or cutaneous reactions during desensitization as well as followup. It is well tolerated in all patients, including the three critically ill patients. As judged by the outcome and ability to tolerate trimethoprim-sulfamethoxazole after desensitization, the procedure is successful in all patients in this study. Equipped with this protocol one can evaluate possible mechanisms of desensitization such as oral tolerance or mediator depletion in a controlled fashion.     

Therapy concepts in chronic hepatitis C

Patients with persistently normal transaminases and without inflammatory changes or fibrosis in liver biopsy have a low risk for progression, respond poorly to antiviral therapy and should thus not be treated for the present. Patients with significant histologic activity or advanced stage of fibrosis are at risk for progression towards cirrhosis. The risk is significantly increased with chronic alcohol consumption even in moderate doses. Treatment with interferon alone results in sustained virological remission in less than 20% of these patients. Treatment success, however, is 2 to 6 times higher under combined treatment with interferon plus ribavirin. The response rate may be further increased with high-dose and daily interferon administration (inductive dosing). The best treatment option for patients with chronic hepatitis C, therefore, is their inclusion in one of the study protocols (examining combinations and induction) currently active in Switzerland.     

A mathematical approximation for the solution of a static indentation test

The aim of this study was to compare the incidence of acute adverse events and long-term outcome of two different surfactant dosing procedures in respiratory distress syndrome (RDS). The effects of two surfactant dosing procedures on the incidence of transient hypoxia and bradycardia, gas exchange, ventilatory requirements and 28 d outcome were compared. The patients, comprising 102 infants (birthweight 600-2000 g) with RDS on mechanical ventilation with FiO2 > or = 0.4, were randomized at 2-24 h to receive 200 mg kg(-1) of Curosurf; in 56 it was given by bolus delivery, and in 55 by a simplified technique (dose given in 1 min via a catheter introduced through a side-hole in the tracheal tube adaptor. The baby's position was not changed and ventilation was not interrupted). Two additional surfactant doses (100 mg kg(-1)) were also given, by the same method, if ventilation with FiO2 > or = 0.3 was needed 12 and 24 h after the initial dose. The number of episodes of hypoxia and/or bradycardia was similar in both groups. A slight and transient increase in PaCO2 was observed in the side-hole group. The efficacy of the surfactant, based on oxygenation improvement, ventilator requirements, number of doses required and incidence of air leaks, was similar. No differences were observed in the incidence of intraventricular haemorrhage, patent ductus arteriosus, bronchopulmonary dysplasia or survival. In conclusion, a simplified surfactant dosing procedure not requiring fractional doses, ventilator disconnection, changes in the baby's position or manual bagging was found to be as effective as bolus delivery. The number of dosing-related transient episodes of hypoxia and bradycardia was not decreased by the slow, 1 min, side-hole instillation procedure.     

Importance of hierarchy content in the self-control of anxiety.

Used speech anxiety as the target behavior in a study which compared 2 self-control desensitization procedures: one with a hierarchy relevant to speech anxiety and the other with a hierarchy totally unrelated to public speaking situations. A 3rd treatment condition involved the prolonged exposure of the hierarchy relevant to speech anxiety in the absence of relaxation. 42 speech-anxious community residents volunteered to participate in the program and were seen in groups for 7 therapy sessions. Using a variety of different outcome measures, consistent anxiety reduction was found after each of the 2 desensitization treatments. These were equally effective, indicating that the generally accepted procedure of using hierarchies reflecting target behavior may be an unimportant component of desensitization, at least as presented within a self-control framework. Although the 2 desensitization procedures were somewhat superior to the prolonged exposure, the latter also resulted in anxiety reduction. (1 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reversible oxacillin hepatotoxicity

Eight patients developed elevations of hepatic enzymes while receiving oxacillin intravenously. In all instances the patients were asymptomatic and anicteric. Peripheral eosinophilia was present in five of eight patients. In each patient change of therapy to a different pencillinase-resistant penicillin or to penicillin G was associated with a rapid decrease in liver function abnormalities and evenutal return of the enzymatic values to normal. Change of medication to an alternative penicillinase-resistant penicillin or to penicillin G is suggested as a safe procedure for completion of antistaphylococcal therapy in patient who develop oxacillin-related hepatotoxicity.     

In vitro and in vivo efficacy of the triazole TAK-187 against Cryptococcus neoformans

Multiple isolates of Cryptococcus neoformans, including those with fluconazole resistance, were tested to assess the in vitro activity of the new triazole TAK-187. MICs of TAK-187 were at least eightfold lower than those of fluconazole, and fungicidal concentrations for most isolates were 4 microg/ml or less. TAK-187 also was evaluated as intermittent therapy using two dosages in a rabbit model of experimental cryptococcal meningitis. Compared to daily treatment with fluconazole, as little as two doses of TAK-187 given 7 days apart were found to be effective. Plasma and cerebrospinal fluid TAK-187 concentrations were many times higher than MICs and fungicidal concentrations. Based upon its therapeutic efficacy and long half-life in the rabbit model, TAK-187 should be investigated for intermittent dosing in treatment or suppression of cryptococcal infections in humans.     

Lung tumor induction in A/J mice by the tobacco smoke carcinogens 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and benzo[a]pyrene: a potentially useful model for evaluation of chemopreventive agents

The purpose of this study was to establish a lung tumor model for the evaluation of chemopreventive agents against lung cancer in smokers. Lung tumor induction in A/J mice by 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and benzo[a]pyrene (BaP) was studied using protocols in which these two tobacco smoke carcinogens were given individually or in combination. Groups of female A/J mice were treated by either intragastric gavage (i.g.) or by intraperitoneal injection (i.p.) with various doses of NNK and/or BaP for 8 consecutive weeks. The mice were killed either 9 or 19 weeks later and tumors of the lung and forestomach were counted. The i.g. route of administration proved to be more satisfactory than i.p. administration, because it avoided complications due to tumor formation at the injection site and associated mortality. A dose-response relationship for lung tumor induction by i.g. administration of NNK and BaP in combination was established in the mice killed 9 or 19 weeks after completion of carcinogen treatment. The highest total doses of NNK and BaP (a total of 24 mumol of each) induced more lung tumors than would have been expected by extrapolation from the lower doses. Comparisons of NNK and BaP given individually showed that BaP was more tumorigenic to the lung than NNK when given by the i.g. route; i.p. administrations of BaP were complicated by local tumor formation and mortality. The most favorable dosing regimen of NNK and BaP for evaluation of chemopreventive agents appears to be a total dose of 24 mumol of each, administered in eight weekly subdoses i.g., with sacrifice 9 weeks after completion of dosing. This regimen induced 10.5 +/- 4.4 lung adenomas/mouse. A combination of benzyl isothiocyanate and phenethyl isothiocyanate, given 2 h prior to each gavage of NNK and BaP, was found to be an effective inhibitor of lung tumor formation, reducing the tumor multiplicity to 5.9 +/- 5.7 lung adenomas/mouse (P < 0.001) and completely inhibiting forestomach tumor development. The results of this study provide a convenient model for assessing the efficacy of chemopreventive agents against lung cancer induction by tobacco smoke carcinogens.     

Evaluation of gentamicin pharmacokinetics and dosing protocols in 195 neonates

Gentamicin pharmacokinetics and dosing protocols in neonates were studied. Demographic and pharmacokinetic data on 202 neonates treated with gentamicin at a 500-bed medical center were collected over a three-year period. Administered doses, gentamicin concentration measurements, and recorded times were used to calculate each patient's clearance, volume of distribution, elimination rate constant, and half-life. The performance of 15 dosing protocols, including 6 previously published ones and 9 developed on the basis of the study, was evaluated using the pharmacokinetic data. Of the 202 patients, 195 were included in the analysis. The mean +/- S.D. clearance, volume of distribution, elimination rate constant, and half-life were 0.047 +/- 0.015 L/hr/kg, 0.45 +/- 0.11 L/kg, 0.107 +/- 0.032 L/hr, and 7.19 +/- 2.64 hours, respectively. Weight, urine output, gestational age, and postconceptional age (PCA) had the highest correlation with the pharmacokinetic values. Blood urea nitrogen concentration (BUN) and Apgar score were poor predictors of the pharmacokinetic values. There were no significant differences among patient subsets based on race and BUN, but subset analysis based on PCA did indicate significant differences. In simulations, the protocols based on the study patients tended to perform better than the literature protocols, with all but three achieving therapeutic goals in 75% or more of the neonates. Of the published protocols, Murphy and Carter's produced the greatest percentage of neonates with peaks from 5 to 10 mg/L and troughs of <2 mg/L. The devised protocols tended to perform poorly in producing troughs between 1 and 2 mg/L, yet performed comparatively well in providing therapeutic peaks from 5 to 10 mg/L.