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Biomedical subjects

R R Maddox

Publications and source records attributed to R R Maddox.

14 recordsLinked to original sources
PubMed1986

Umbilical versus peripheral tobramycin administration.

This study evaluated the disposition of tobramycin (T) after umbilical artery catheter (UAC), intravenous (i.v.), and intramuscular administration to a group of 12 premature neonates. Patients varied in gestational age (31-42 weeks) and weight (1.76-3.98 kg). Each neonate received a 2 mg/kg dose of T at 12-h intervals for 2-15 days. Multiple blood samples after the first and last doses of T, as well as daily measurements, were made during the course of therapy. Analysis of drug concentration data revealed a biphasic distribution of T, which required a two-compartment model for description. Mean values for the alpha and beta elimination phases, t1/2 beta, Vc, and Vdss after the first dose of T were 7.604 h-1, 0.087 h-1, 11.18 h, 0.214 L/kg, and 0.645 L/kg, respectively. Average drug clearance (ClT) increased during therapy from 71 to 103 ml/min, associated with an increase in the renal function of patients. Serum concentrations of T were out of the therapeutic range in 50% of study patients. The variability of drug clearance in the neonate requires the measurement of T concentration in order to ensure safe and effective therapy.

Female↗
PubMed1983

Effect of secobarbital on theophylline clearance.

Increased clearance of theophylline after the administration of secobarbital was observed in a child receiving phenobarbital. Prior to barbiturate treatment, theophylline clearance was 4.78 ml/kg/min. Beginning 10 days after the institution of secobarbital and phenobarbital therapy, a continually increasing amount of theophylline was required to maintain therapeutic serum concentrations. After 29 days of barbiturate administration, theophylline clearance attained a peak value of 16.1 ml/kg/min, an increase of 337% from the prebarbiturate rate. During this time it was necessary to administer theophylline at a dosage four times above that usually recommended. After secobarbital was discontinued, theophylline clearance returned to 4.53 ml/kg/min. The decrease in theophylline clearance occurred while phenobarbital dosage remained stable. It is apparent that changes in secobarbital dosing were subsequently followed by changes in the clearance of theophylline.

Drug Interactions↗
PubMed1982

Team approach in providing clinical pharmacokinetic services.

A team approach to clinical pharmacokinetic services at a university hospital is described. The clinical pharmacokinetics team (CPT) developed as an outgrowth of a clinical pharmacokinetic service (CPS) as the workload of the service expanded. The CPT serves to: (1) maximize the quality and continuity of clinical pharmacokinetic care; (2) provide a teaching medium for students at the baccalaureate and graduate level; and (3) stimulate the development of clinical pharmacokinetic research. The CPT is responsible for patients in those medical services that are not regularly served by a clinical pharmacist. The structure of the CPT includes an attending clinical pharmacist with a hierarchy of subordinate practitioners ranked by their individual didactic and clinical experience in pharmacokinetics. Students participate in (1) work rounds, where collective discussions of patient evaluations occur, and (2) one-to-one student-preceptor clinical assessments of patients' drug therapy. The attending clinical pharmacist conducts CPT rounds daily, and the students and residents must convey information to the team on: (1) the drug therapy prescribed and the appropriate monitoring methods, (2) the working diagnosis and plan of treatment, (3) results of laboratory and clinical assessments, and (4) details of patient interviews. The CPT is also responsible for ongoing clinical pharmacokinetic research. The team approach to clinical pharmacokinetic services has provided a framework for the education of clinical pharmacists while stimulating research and providing direct patient care.

Education, Medical↗
PubMed1981

A computer system for the storage and retrieval of clinical pharmacokinetic data.

A computer system is described which stores patients data relating to clinical pharmacokinetic assessments made by clinical pharmacists, who are participating in a clinical pharmacokinetics service. The system was developed to assist in the documentation of service activities and storage of patients' pharmacokinetic data. An additional component of the system is the ability for retrospective review of the stored data. Application of this system to the derivation of new information on drug pharmacokinetics and drug efficacy/toxicity in various patient groups is discussed. The implications for phase IV drug studies and toxicity screening studies is also described.

Computers↗
PubMed1981

The interaction of spironolactone and digoxin: a review and evaluation.

A review of the literature describing the interaction of digoxin and spironolactone is presented. Two mechanisms of possible interaction are discussed. Spironolactone and its metabolites may interfere with digoxin radioimmunoassay or alter the pharmacokinetics of digoxin. The occurrence of either or both of these processes may make interpretation of serum digoxin levels difficult.

Digoxin↗
PubMed1981

Collaborative clinical pharmacokinetic services.

A program for routine pharmacokinetic interpretation of serum analyses of gentamicin, tobramycin, amikacin, phenytoin, phenobarbital, theophylline, lidocaine, digoxin, quinidine, and procainamide at the Medical University of South Carolina Hospital is described. Results of all analyses of serum for the drugs listed are evaluated by a pharmacist trained in clinical pharmacokinetics. Patient variables relevant to the determination of drug serum concentrations, drug elimination, distribution, and dosage are given appropriate consideration in each evaluation. A summary of the pharmacokinetic interpretation and any necessary modification of drug dosage regimens are then written into the progress notes of the patients' medical records. Approximately 12 patients and 20 drug concentrations are evaluated each day. The average charge for te service is +35. This service, which is reimbursed by third-party carriers, has resulted in improved use of laboratory personnel, equipment, and time and has provided a framework for education and research as well as a mechanism for direct contributions to patient care by the pharmacist.

Hospital Bed Capacity, 500 and over↗
PubMed1980

Automated pharmaceutical assistance systems. I. Clinical pharmacokinetics. II. Drug interference with laboratory tests results.

The function of the clinical pharmacokinetic service (CPS) in University Hospital is described. A methodological procedure was developed for routine interpretation of specified drug serum levels. Work lists that identify analytical procedures to be included for clinical pharmacokinetic evaluation are prepared daily. The results of all analyses of serum drug levels are evaluated by a pharmacist who is trained in clinical pharmacokinetics. Patient variables that influence serum levels of drugs are mathematically manipulated by program logic. Projections of expected drug levels as a result of dosing regimens are made and compared to measured laboratory results. Iterative programming that modifies projections on the basis of actual measurements is employed to determine individual drug dosing regimens that provide therapeutic/nontoxic serum levels of drugs. The drug/test interference system, which accesses the CPS data base, provides information concerning the potential physiologic, therapeutic, or toxic effect of drugs on biochemical substances. The system allows display of data concerning each drug before it is administered. Information concerning the date and time of initiation and termination of drug therapy allows for a warning comment to be attached automatically to the appropriate laboratory test result if interference is indicated.

Computers↗
PubMed1977

Double-blind study to investigate methods to prevent cephalothin-induced phlebitis.

Methods which might be useful in preventing cephalothin-induced phlebitis following intravenous administration of the buffered drug were investigated. One hundred and twenty adult orthopedic patients were assigned randomly to either a control group or one of five treatment groups. The treatment regimens studied were: addition of hydrocortisone phosphate 10 mg to each liter of intravenous fluid; addition of heparin 1,000 units to each liter of intravenous fluid; addition of heparin 500 units and hydrocortisone phosphate 1 mg to each liter of intravenous fluid; addition of heparin 1,000 units and hydrocortisone phosphate 10 mg to each liter of intravenous fluid; and filtration of intravenous solutions through a 0.22-mum inline filter. All patients in the study received intravenous buffered cephalothin at a dosage of 1 g every six hours for a minimum of 48 hours. Phlebitis was assessed every 12 hours according to predetermined criteria. Significant differences were found in the incidence of phlebitis at 48 hours between the control group and the last three study groups (see above). It is concluded that postinfusion phlebitis following cephalothin administration can be reduced by the concomitant addition of heparin and hydrocortisone to the intravenous solution or by the use of an inline 0.22-mum final filter.

Adolescent↗
PubMedDate not supplied

Effect of inline filtration on postinfusion phlebitis.

The effect of inline i.v. filters on postinfusion phlebitis (PIP) and bacterial colonization of i.v. catheters was evaluated. The subjects of the prospective double-blind study were 195 men undergoing elective surgery. Polyethylene i.v. catheters of varying sizes were inserted the morning of surgery. Before catheterization, each site was shaved and cleansed with 1% povidone-iodine solution. In the experimental group, all i.v. fluids, additives, and medications were administered through a 0.22-micron micropore inline final filter. In the control group, no membrane filter was present in the filter housing. Drug and fluid therapy were determined by the physician, and flow rates were maintained at 40 ml/hr if not specified. Every 12 hours, sites were inspected and observations were graded according to criteria adapted from an earlier study. The incidence of phlebitis in the two groups was compared. At the termination of i.v. therapy, catheters were removed and cultured. The incidence of PIP in the experimental group (38/95) and the control group (39/100) was not significantly different. There were no differences between groups in variables possibly related to the occurrence of PIP, such as patient age, i.v. flow rate, catheter size, and use of potassium chloride i.v. additive. Of 141 i.v. catheters that were cultured, 25 yielded 10 or more colonies per plate; 21 were coagulase-negative staphylococci. Positive cultures occurred as frequently in patients without filters as in those with filters. No patient had clinical evidence of bacteremia. In these general surgical patients, inline filters did not affect the incidence of PIP or bacterial colonization of i.v. catheters. While the use of inline filters to prevent infusion of microorganisms deserves consideration, their routine use as a means of reducing PIP is unwarranted.

Adult↗