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Biomedical subjects

R R Bailey

Publications and source records attributed to R R Bailey.

At least 109 records · Page 6Linked to original sources
PubMed1990

The pharmacokinetics and pharmacodynamics of quinapril and quinaprilat in renal impairment.

1. The pharmacokinetics and pharmacodynamics of quinapril and its active metabolite quinaprilat were studied in 20 subjects with renal function varying from normal to severe renal failure, during the approach to and at steady-state, and for 72 h after cessation of quinapril 20 mg orally for 7 days. 2. The apparent oral plasma clearance of quinaprilat (dose of quinapril equivalent/AUC of quinaprilat) was directly related to creatinine clearance (CLCr). The predicted apparent oral clearance of quinaprilat was zero when CLCr was zero, suggesting minimal extrarenal elimination. 3. Peak and trough concentrations of quinaprilat, and its apparent elimination half-life, varied inversely with CLCr. 4. Trough concentrations of quinaprilat showed no accumulation between 2 and 7 days, even in severe renal impairment. 5. There was a weak relationship between the oral plasma clearance of quinapril and CLCr. 6. ACE inhibition was marked and prolonged in all subjects, with 50% inhibition at 2.7 +/- 1.9% ng ml-1 of quinaprilat. The time for which ACE inhibition was greater than 90% was related inversely to CLCr. 7. Aldosterone concentrations and plasma renin activity responded in a predictable way, but with no clear relationship To CLCr. 8. Atrial natriuretic peptide concentrations were not affected by quinapril administration. 9. Glomerular filtration rate, as measured by Tc99mDTPA clearance, was not affected by quinapril administration. 10. Blood pressure at steady-state decreased significantly in the subjects with hypertension. The changes in blood pressure were not related to renal function. 11. These results suggest that the dosage rate of quinapril may have to be altered in renal impairment.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗
PubMed1990

Disseminated prostatic carcinoma presenting with acute interstitial nephritis and microangiopathic haemolytic anaemia.

A 74-year-old man with metastatic prostatic carcinoma developed acute oliguric renal failure, a microangiopathic haemolytic anaemia and thrombocytopaenia. A renal biopsy showed an acute interstitial nephritis but no changes suggestive of the haemolytic uraemic syndrome. He recovered normal renal function after treatment with haemodialysis and prednisone 20 mg daily for five days. Previous assumptions about the renal lesion in patients with malignancy-associated microangiopathic haemolytic anaemia may need review.

Acute Disease↗
PubMed1990

Brief overview of single-dose therapy for uncomplicated urinary tract infections.

The published studies of the use of single-dose antimicrobial therapy for the treatment of urinary tract infection have been reviewed. In women a single dose of any of several antimicrobial agents is as effective as a course of treatment for uncomplicated urinary tract infections caused by Escherichia coli. Trimethoprim or co-trimoxazole are currently the preferred agents for single-dose therapy. Fosfomycin trometamol and the 4-quinolones are promising agents. Failure of single-dose therapy may prove to be a simple guide as to the need for further urinary tract investigation or more intensive therapy. Single-dose antimicrobial therapy is now the treatment of choice for uncomplicated urinary tract infections in general practice.

Bacteriuria↗
PubMed1990

Anemia and angiotensin-converting enzyme inhibition in renal transplant recipients.

The renin-angiotensin system has been shown to have an effect on erythropoietin synthesis and hemoglobin concentration. We present a retrospective study of stable renal transplant recipients who received an angiotensin-converting enzyme (ACE) inhibitor as treatment of hypertension. Fifteen patients were eligible, with a mean hemoglobin concentration of 130.7 +/- 22.7 g/L (SD). Within 6 months of ACE-inhibitor therapy, the mean hemoglobin had fallen significantly to 110.5 +/- 23.2 g/L (p less than 0.001). No parallel change in leukocyte or platelet counts was evident. Prospective studies are needed to clarify the effect of inhibition of the renin-angiotensin system on erythropoietin synthesis and release.

Anemia↗
PubMed1989

Effects of cilazapril on renal function and hormones in hypertensive patients with renal disease.

The effects of cilazapril 2.5 to 5.0 mg every 24 hours orally for one month on blood pressure, renal hemodynamics, and plasma and urinary hormones were investigated in 11 patients with renal disease and hypertension. Six patients had renal failure (pretreatment creatinine clearance of less than 1 ml/second). Both systolic and diastolic blood pressures were significantly decreased in all patients and seven of the 11 required 5.0 mg daily. There was no significant change in the effective renal plasma flow, glomerular filtration rate, or creatinine clearance, although the renal vascular resistance was significantly reduced. Albuminuria was reduced in most patients but the mean change was not significant. The mean plasma potassium concentration rose significantly, but no changes in electrolyte excretion or weight were noted. Mean ambulant plasma renin activity was normal before treatment and rose significantly. Mean ambulant angiotensin II concentrations did not change. Mean ambulant plasma aldosterone concentration and mean urinary aldosterone excretion decreased significantly. Plasma arginine vasopressin and cortisol concentrations did not change. No changes were noted in plasma glucose concentrations, liver function tests, hemoglobin concentrations, or white blood cell or platelet counts. A slight looseness of bowel motions occurred in two patients and was the only side effect recorded. Cilazapril appears to be an effective and safe antihypertensive drug in patients with hypertension and renal disease.

Adult↗
PubMed1989

Hyperkalaemia in patients in hospital.

A survey of all laboratory blood specimens with a plasma potassium concentration greater than or equal to 5.5 mmol/L was conducted over a three month period. Of 331 specimens with hyperkalaemia, 71 were excluded because the specimens was haemolysed, old or contaminated. The laboratory served a population of 348,561 and during this time measured the plasma potassium on 25,016 occasions. Sixty-six outpatients and 20 neonates were not evaluated. The survey was undertaken on 86 of 102 inpatients (46 males), 48 of whom were over 66 years of age. Fifty-seven patients were admitted under a medical service and 29 under a surgical service. Fifty-nine had a single episode of hyperkalaemia. Thirty-two underwent a surgical procedure. The commonest contributing factor was impaired renal function which was present in 71 (83%) patients. Although a definitive causative role for drugs could be identified in only five patients, in 52 (60%) patients drugs were a contributing factor (potassium supplements 24, ACE inhibitors 16, nonsteroidal antiinflammatory drugs 12). Thirty-five of the 86 (41%) patients died during their hospital admission. Nineteen of the 35 deaths occurred within three days of the hyperkalaemia being recorded. A normal plasma potassium was eventually documented in 50 of the 86 patients. Of the remaining 36 patients, 25 (69%) subsequently died. In general the treatment of patients with hyperkalaemia focused on identifying and treating the underlying cause. Hyperkalaemia must always be considered seriously and regard given to the overall clinical status of the patient, with particular attention to drug therapy, renal and cardiac function, acid base status and the possibility of sepsis.

Adolescent↗
PubMed1989

Remission induced by chlorambucil in steroid-responsive, frequently relapsing nephrotic syndrome that relapsed after cyclophosphamide.

Five patients with a steroid-responsive, frequently relapsing nephrotic syndrome who had failed at least one course of treatment with cyclophosphamide were all put into a long term remission with chlorambucil. One patient developed a severe neutropenia and herpes zoster and another with an epileptic tendency developed myoclonic jerks. The indications and potential hazards of using chlorambucil in this context are discussed.

Administration, Oral↗
PubMed1989

The pharmacokinetics of angiotensin converting enzyme inhibitors in patients with renal impairment.

The clearance of drugs excreted entirely unchanged by the kidneys is assumed to relate directly to renal function. The clearance of drugs which are entirely metabolized is usually not altered in patients with renal impairment, although there are examples of both increased and decreased metabolic clearance rates. The clearance of metabolites which are excreted unchanged through the kidneys is also directly related to renal function. The angiotensin converting enzyme (ACE) inhibitors enalapril, ramipril, cilazapril and quinapril are prodrugs that are rapidly converted to active metabolites which are excreted unchanged through the kidneys. Studies have consistently demonstrated reduction in the apparent oral clearance of the active metabolites, in proportion to the degree of impairment of renal function. In addition, for quinapril at least, the metabolic clearance of the parent drug is slightly reduced in renal impairment. The activity of captopril and lisinopril lies in the parent molecule itself. Lisinopril is excreted renally unchanged, while captopril is both metabolized and excreted renally unchanged. The duration of ACE inhibition after administration of any of the ACE inhibitors is prolonged in proportion to the degree of renal impairment. From these pharmacokinetic and pharmacodynamic properties, it follows that the dose rate of the ACE inhibitors should be reduced in direct proportion to the degree of reduction in renal function. Reducing the dose, rather than prolonging the dose interval, is more logical for compliance and for maintaining a consistent degree of ACE inhibition over 24 h.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1988

Comparative study of norfloxacin and trimethoprim for the treatment of elderly patients with urinary tract infection.

One hundred elderly hospitalised patients, aged 70 to 97 years (mean 81.7 years; SD 7.1 years) with a urinary tract infection were entered into a randomised study to compare the efficacy, safety and tolerance of norfloxacin 400 mg twice daily for three days with trimethoprim 300 mg once daily for three days. Forty-two of 49 patients (86%) were cured with norfloxacin, compared with 35 of 51 (69%) with trimethoprim (p less than 0.05). No patient reported any side effects during treatment. Two patients treated with norfloxacin and three treated with trimethoprim developed a disturbance of liver function. Three deaths occurred within 28 days of treatment with trimethoprim but were unrelated to the treatment. In this study norfloxacin proved superior to trimethoprim for the treatment of uncomplicated urinary tract infections in elderly hospitalised patients.

Aged↗