The influence of hydrochlorothiazide on the pharmacokinetics of enalapril in elderly patients

In a randomized, cross-over, single-dose study of 19 elderly hypertensive patients (aged 62-84 y, SBP greater than 160 mmHg, DBP greater than 100 mmHg, creatinine clearance 11-93 ml.min-1) we have studied the pharmacokinetics of the angiotensin converting enzyme (ACE) inhibitor enalapril after a single oral dose of either 10 mg enalapril or 10 mg enalapril + 25 mg hydrochlorothiazide. The pharmacokinetics of enalapril were unaffected by hydrochlorothiazide, but there was a significant reduction in renal clearance and a significant increase in AUC(0-24 h) of enalaprilat after hydrochlorothiazide, resulting in higher serum concentrations of the active drug. This was independent of the individual degree of renal impairment and might be due either to an initial reduction of GFR by hydrochlorothiazide or to interference with the tubular secretion of enalaprilat. The relationships between serum enalaprilat and serum ACE activity were similar after both treatments, both consistent with a value for Ki of enalaprilat of about 0.1 nmol.l-1. Thus, serum ACE activity was not affected by hydrochlorothiazide but completely reflected the pharmacokinetics of enalaprilat in both treatments.

Specific interchain cross-linking of antibodies using bismaleimides. Repression of ligand leakage in immunoaffinity chromatography

The extensive use of antibody-containing affinity columns in the purification of biologically active compounds (e.g., genetically engineered proteins) is severely hampered by the leaching of antibody (or portions thereof) from the immunoaffinity resin during elution of the target antigen. One of the major problems in this context is the combined use of reducing (i.e., thiols) and chaotropic (e.g., detergents and denaturants) agents in the elution step, which causes the disassociation of heavy and/or light chains from the immobilized antibody, thereby contaminating the resultant product. In order to overcome this problem, we have cross-linked the four antibody chains at their sites of disulfide interlinkage, thus producing a single antibody chain. To accomplish this, interchain disulfide bonds were reduced, and the resultant thiol groups were cross-linked by using bifunctional SH-specific reagents (particularly bismaleimides). Cross-linking of up to 95% of the available SH groups produced was achieved with concomitant retention of antigen-binding activity. The cross-linked antibody was immobilized onto CNBr-activated Sepharose, and the resultant column was found to be substantially more stable to harsh elution conditions than similar columns which contain the un-cross-linked antibody.

[Lipoprotein metabolism in menopause. Effect of hormonal substitution therapy]

Oral administration of conjugated estrogens, estradiol valerate and micronized estradiol--but not the percutaneous application--in the postmenopause modifies the plasmic lipoprotein profile by lowering, dose-dependently, LDL and elevating HDL (HDL2). In parallel, the cardiovascular mortality is decreased by 50-66%, with smokers also benefiting to the same extent. On account of the increased risk for endometrial carcinoma associated with postmenopausal estrogen monotherapy, combination with a lowest-dose gestagen is imperative. However, the very numerous synthetic gestagens can antagonize the favorable effects of the estrogen on lipoprotein metabolism. This applies in particular to the gestagens of the 19-nortestosterone type, such as norethisterone acetate and, in particular, levonorgestrel, but less so the 17-hydroxyprogesterone derivatives medroxyprogesterone acetate and medrogestone with their very low androgenic effect.

Clinical pharmacology in the elderly - an example of interdisciplinary cooperation between basic research and clinic

Elderly patients with multiple diseases are often more sensitive to the effects of drugs than younger ones. The simultaneous ingestion of various drugs can invite drug interactions. Moreover, age-induced physiological and pathological changes can influence pharmacokinetics and pharmacodynamics. Compared with earlier periods of life, we still know very little about pharmacokinetics and pharmacodynamics in old age; it follows that in patients with multimorbidity closer monitoring and a more accurate diagnosis, before drug therapy is instituted, are of far greater importance than wholesale prescription and the isolated treatment of individual diseases against the background of multiple pathology.

Effect of including recommendations for antimicrobial therapy in microbiology laboratory reports

Innovative approaches are needed to improve cost-effective antibiotic use in hospitals. We established an algorithm to provide a recommendation for both a single oral and a single parenteral antimicrobic, including dosage, to be placed in the bacteriology laboratory report for therapy guidance of 174 episodes of lower respiratory infection in a group of "program" patients with no evidence of infection at other sites. The initial recommendation was based on the Gram-stained direct smear of secretions. The recommendation was updated when preliminary culture results were available, and again with final identification and susceptibility data. We compared the severity of illness, length of stay, and cost of therapy for 68 episodes in program patients who received the recommended therapy with 111 episodes in a control group of patients who received antimicrobial therapy but for whom no recommendations were reported. There was a significantly greater use of the recommendations for sicker patients. Antimicrobial therapy, in general, was more often used for the program patients than for the controls. There was no difference in length of stay or therapy cost. We recommend that this approach be used in settings where there is more problematic use of antimicrobics.

[Pharmacokinetics and pharmacodynamics of flunarizine in multimorbid, geriatric patients with vertigo]

Ten multimorbid, geriatric, hospitalised patients, mean age 76 years, were treated for vertigo and received 10 mg flunarizine (CAS 52468-60-7; Sibelium) daily for 3 weeks. The study of the pharmacokinetics and pharmacodynamics of this dosage scheme revealed that the kinetics did not change during the three weeks of therapy. The terminal half-life is 7.3 +/- 3.3 days. Since a steady state concentration is only to be expected after about 5 half-lives, this condition was not fully met yet in most patients after three weeks. The data obtained from the patients examined are essentially identical with those in young and old healthy subjects. The unchanged kinetics during long-term treatment prevent side-effects due to cumulation on the one hand or the decrease of plasma levels to inactive concentrations resulting from enzyme induction. There was not measurable anti-aggregator effect on thrombocytes or erythrocytes. The effectiveness in connection with vertigo seems to be due to a direct labyrinth depressor activity and/or to a selective vasospecific action. No side-effects were observed during the three weeks of therapy.

Age dependency of the sialic acid content of fibrinogen. consequences for erythrocyte aggregation

Sialic acid (SA) content of plasma proteins and fibrinogen was investigated in 60 persons of different age and health status. SA/mg fibrin rose with age and morbidity in plasma, rinsed clots of fibrin from plasma and after prothrombin adsorption as well as in fibrin clots prepared from purified fibrinogen. The higher plasma SA is caused by increasing concentrations of glycoproteins like fibrinogen, but also by a higher content of SA/mg protein, as has been shown for fibrinogen. SA is considered to be an unspecific marker of acute phase reactions. Changing SA content of glycoproteins may have functional consequences. An increased red cell aggregation with fibrinogen of healthy elderly correlated with its SA content, but SA is most probably only indicating an altered protein heterogeneity in the aged and not a causative factor that influences erythrocyte aggregation.

[Garlic as phytogenic antilipemic agent. Recent studies with a standardized dry garlic powder substance]

Garlic (Allium sativum L.) is a commonplace drug. It is now available in the form of dragees made of garlic powder, standardized to 1.3% alliin. The lipid-lowering potential of such preparations has not been reviewed yet. In 7 out of 8 studies, including over 500 patients, a daily dose of 0.6 g to 0.9 g garlic powder reduced plasma cholesterol and triglyceride levels by 5 to 20 percent. The metabolic mechanisms of these reductions are not known.

[Age related changes in the liver. Consequences for drug therapy]

The most significant morphological peculiarity of the liver in old age is "brown atrophy", with a reduction in weight and volume of the organ. The physiological metabolic functions of the liver are extremely well preserved right up into very old age. There is, however, some impairment of function with respect to the elimination of exogenous substances and drugs. The major cause of this is a decrease in hepatic perfusion, the volume of the liver, and the number of functioning hepatocytes. Thus, since the elimination capacity of both the kidneys and the liver can be reduced in old age, drugs should initially be administered at lower doses in geriatric patients.

[Combination drugs in geriatrics. The need for clinical studies in this special age group]

Multimorbidity frequently prompts the use of multiple drugs with the aim of treating the individual diseases simultaneously. Ingestion of a number of different drugs incurs the risk of early and more frequent side effects, as well as interactions between the various drugs. There is a tendency among patients of all age groups, intentional or unintentional not to take their medication. Among elderly patients regular compliance is a special problem. Reduction of the high consumption of drugs by the elderly is possible by therapy with combination drugs. The present paper discusses the advantages and disadvantages.

The effect of a garlic preparation on the composition of plasma lipoproteins and erythrocyte membranes in geriatric subjects

This study evaluated the effect of a dried garlic powder preparation, standardised to 1.3% alliin, on the composition of plasma lipoproteins and erythrocyte membranes. Forty volunteers, aged 70 years and over, took 600 mg of garlic powder per day for three months. In participants with initially normal plasma cholesterol levels (CH less than 200 mg/dl; n = 11) after three months of garlic tablet administration, little or no change in CH values was registered, as for most of the other parameters. In contrast, in volunteers with initially elevated CH levels (CH greater than 200 mg/dl, n = 29), the CH levels were reduced by -7.7% (p less than 0.001). This reduction took place primarily in the esterified cholesterol fraction (-12%, p less than 0.001), whereas free cholesterol concentrations were not altered significantly. Triglycerides (-15.9%, p less than 0.05) and plasma choline phospholipids (-4.6%, p less than 0.01) were also reduced. No change of the plasma LDL-CH to HDL-CH ratio was observed in this group. Based on the weight of lyophilised, haemoglobin-free erythrocytes, the mean membrane concentration of phospholipids and cholesterol in the total cohort (n = 40) increased by 5.7% (p less than 0.001) and 6.1% (p less than 0.01), respectively. These increases were more pronounced the lower the body mass indices (kg/m2) were, and the longer the duration of garlic administration was. The molar ratio of membrane phospholipids to cholesterol remained unchanged. The results are discussed with regard to a possible role of the garlic-induced membrane effects in the plasma lipid-lowering potency of garlic and preparations made from it.

Pharmacokinetics of drug overdose

Drugs ingested in overdose can have altered pharmacokinetics of absorption, distribution, and elimination. The pathophysiologic consequences of overdose can also change a drug's pharmacokinetic properties. Many toxicologic interventions are based on modifying the drug's pharmacokinetics (e.g., impairing absorption or enhancing elimination). Serum drug monitoring, even with its limitations, does have a role in managing the patient who has taken an overdose.

Age-dependent differences in the gait of rats

Middle-aged (16-17 month) and aged (29 resp. 31-33 month) female Sprague-Dawley rats were assessed for age-dependent changes in gait. Stride length and gait symmetry decreased significantly with age. Stance width distributions changed from normal to bimodal. Changes in stride length and stance width were even significantly different between 29 and 31 months of age. Their retest reliability was high for middle-aged and aged rats. All three parameters have a potential as markers of aging or disease for intra- and interindividual comparisons.

Developing staff into clinical practitioners

Developing clinical skills in pharmacy staff is a process that can enhance the services of a pharmacy department and improve the professional development and interest of the staff. Staff should be included in the development of a clinical philosophy and a training and ongoing development program that will achieve the desired goals should be planned. An MBO process may help to track the individual pharmacist's progress. Knowledgeable, motivated staff are the key ingredient in achieving success in providing pharmacy services.