Concentration of teicoplanin in the serum of adults with end stage chronic renal failure undergoing treatment for infection

We examined the adequacy of the following schedule for the administration of i.v. teicoplanin to patients with chronic renal failure: three doses of 6 mg/kg at 12 h intervals, a fourth dose 24 h later and then subsequent doses every 72 h. Eight infected patients undergoing dialysis were investigated, with serum antibiotic concentrations measured ten minutes before and one hour after administration. Mean trough concentrations were 6.9 +/- 3.1 mg/L on day two, 9.8 +/- 4.4 mg/L (day three), 9.2 +/- 4.8 mg/L (day six), 10.9 +/- 5.5 mg/L (day nine), 12.1 +/- 6.1 mg/L (day 12) and 14.8 +/- 8.0 mg/L (day 15). The proposed schedule achieved adequate trough serum teicoplanin concentrations by 48 h in six out of eight patients examined. The dosage regimen was well tolerated.     

Onset and duration of action of single doses of formoterol inhaled via Turbuhaler

The aim of the study was to investigate the time of onset and the duration of the bronchodilating effect of different doses of formoterol administered via Turbuhaler in patients with moderate asthma. Thirty-one patients (five women) with a mean forced expiratory volume in 1 s (FEV1) of 1.97 +/- 0.54 1 and a mean reversibility of 31 +/- 14% of baseline were included in this double-blind, randomized, placebo-controlled and cross-over study. The patients inhaled single doses of placebo, i.e. 6, 12, 24, or 48 micrograms formoterol fumarate, on 5 separate days. Serial measurements of specific airways conductance (SGAW) and FEV1 were performed at regular time intervals for 12 h. The majority of the patients had at least a 50% increase in SGAW within 1-4 min after administration of all active treatments. The maximum increase in FEV1 over placebo was dose-dependent: 12% (6 micrograms), 18% (12 micrograms), 19% (24 micrograms), and 26% (48 micrograms) (P < 0.001). Twelve hours after administration of 6, 12, 24, and 48 micrograms formoterol, the mean increase in FEV1 was still 7%, 15%, 18%, and 27%, respectively, above the value following placebo. Headache was the most frequently reported adverse event in all treatments including placebo. After inhalation of 48 micrograms, three patients experienced mild tremor lasting for less than 1 h; likewise, one patient experienced the same event for 3 h after placebo. Formoterol administered via Turbuhaler10 gave a rapid and dose-related bronchodilating effect lasting for 12 h and was well tolerated.     

Effect of psychotherapy on the course of Crohn''s disease. Results of the German prospective multicenter psychotherapy treatment study on Crohn''s disease. German Study Group on Psychosocial Intervention in Crohn''s Disease

OBJECTIVES: To determine whether a combination of ciprofloxacin hydrochloride and metronidazole hydrochloride would be as effective or more effective than a combination of gentamicin sulfate and metronidazole hydrochloride for preventing infection in patients with penetrating abdominal trauma, to evaluate the factors associated with increased risk of infection, and to determine the serum peak and trough levels of gentamicin with the dosage regimen of 2.5 mg/kg every 12 hours. DESIGN: Randomized double-blind study. SETTING: Level I trauma center. PATIENTS: Eighty-four patients with penetrating intra-abdominal injuries (gunshot wound, 69; stab wound, 15) thought to require laparotomy. INTERVENTIONS: The patients were randomized during treatment in the emergency department to be given a combination of ciprofloxacin hydrochloride, 400 mg every 12 hours, and metronidazole hydrochloride, 500 mg every 6 hours, or a combination of gentamicin sulfate, 2.5 mg/kg every 12 hours, and metronidazole hydrochloride, 500 mg every 6 hours. RESULTS: Of 68 patients with intra-abdominal injuries who could be observed for at least 48 hours after laparotomy, posttraumatic infections developed in 12 (18%), and nosocomial infections developed in 6 (9%). The incidence of posttraumatic infections in patients who were given gentamicin and metronidazole (5/33 [15%]) was not significantly lower than the incidence in patients who were given ciprofloxacin and metronidazole (7 of 35 [20%]; P=.75). The presence of any infection increased the mean+/-SD length of hospital stay from 8.7+/-3.5 days to 23.3+/-10.9 days and increased the mean+/-SD hospital charges from $24 507+/-$9860 to $104920+/-$49083 (P<.001). Univariate analysis showed the factors most significantly associated with infection were as follows: (1) the use of blood transfusions (P<.001), (2) the penetrating abdominal trauma index of 35 or more (P<.002), (3) injury to the colon requiring a colostomy (P=.004), and (4) a trauma score of less than 12 (P<.02). Multivariate analysis showed the only significant factor was the receipt of blood transfusions (F=10.165; P<.005). CONCLUSIONS: Ciprofloxacin and gentamicin, each in combination with metronidazole, were equivalent in their ability to prevent infections after penetrating abdominal trauma; other factors, especially the receipt of blood transfusions, had much more effect on the incidence of infection. Infection greatly increases the length of hospital stay and hospital charges. The use of an increased dosing regimen of 2.5 mg/kg every 12 hours of gentamicin sulfate was effective at obtaining a therapeutic peak serum concentration.     

Effect of gallopamil on myocardial microperfusion in patients with stable effort angina: a randomized, cross-over, double-blind, placebo-controlled trial

We evaluated the efficacy and safety of daily administration of gallopamil 150 mg/day and its effects on myocardial perfusion in a medium-term, randomized, double-blind, cross-over, placebo-controlled trial. We studied 19 patients (17 males and 2 females; mean age 57 +/- 6.8 years) with stable effort angina, angiographically documented coronary artery disease and reversible perfusion defects during exercise thallium-201 myocardial scintigraphy of at least one segment of the left ventricle. After 2 weeks of a single-blind placebo run-in period, during which each patient underwent at least 2 exercise tests and a 48-hour Holter ECG recording, all patients were treated with either placebo or gallopamil 50 mg t.i.d. for 28 days. At the end of this period, patients crossed over to the alternate regimen. This phase was double blind. After treatment with placebo or gallopamil, patients underwent exercise tests, 24-hour Holter ECG recording and thallium-201 myocardial scintigraphy. Weekly angina frequency and trinitroglycerin (TNT) consumption and safety were also evaluated. No patients dropped out of the study because of major side effects. The number of total ischemic and symptomatic events recorded at 24-hour ECG monitoring, weekly angina frequency and TNT consumption were significantly reduced during gallopamil treatment. After gallopamil administration, exercise duration significantly increased (run-in: 419 +/- 116 s, placebo: 420 +/- 118 s, gallopamil: 511 +/- 144 s; p < 0.05), and ST segment depression was significantly reduced (run-in: -1.3 +/- 0.3 mm, placebo: -1.3 +/- 0.3 mm, gallopamil: -0.94 +/- 0.68 mm; p < 0.01), while heart rate, systolic blood pressure and rate-pressure product were unchanged at rest, at submaximal and at peak exercise. Qualitative and quantitative evaluation of myocardial perfusion and the myocardial uptake percentage of thallium-201 in ischemic zones were significantly improved by gallopamil treatment. These findings demonstrate that gallopamil can improve myocardial perfusion and reduce myocardial oxygen consumption.     

Opioid-sparing effects of a low-dose infusion of naloxone in patient-administered morphine sulfate

BACKGROUND: A naloxone infusion is effective in reducing epidural and intrathecal opioid-related side effects. The use of naloxone infusion concomitant with intravenous morphine patient-controlled analgesia (PCA) has not been evaluated, probably because of an expected direct antagonism of the systemic opioid effect. The authors compared the incidence of morphine-related side effects and the quality of analgesia from two small doses of naloxone infusion. METHODS: Sixty patients classified as American Society of Anesthesiologists physical status 1, 2, or 3 who were scheduled for total abdominal hysterectomies were enrolled in the study. Patients received a standardized general anesthetic. In the postanesthetic care unit, patients received morphine as a PCA. They were randomized to receive either 0.25 microg x kg(-1) x h(-1) naloxone (low dose), 1 microg x kg(-1) x h(-1) (high dose), or saline (placebo) as a continuous infusion. Verbal rating scores for pain, nausea, vomiting, and pruritus; sedation scores; requests for antiemetic; and morphine use were recorded for 24 h. Blood pressure, respiratory rate, and oxyhemoglobin saturation were also monitored. RESULTS: Sixty patients completed the study. Both naloxone doses were equally effective in reducing the incidence of nausea, vomiting, and pruritus compared with placebo (P < 0.05 by the chi-squared test). There was no difference in the verbal rating scores for pain between the groups. The cumulative morphine use was the lowest in the low-dose group (42.3 +/- 24.1 mg; means +/- SD) compared with the placebo (59.1 +/- 27.4 mg) and high-dose groups (64.7 +/- 33.0 mg) at 24 h (P < 0.05 by analysis of variance). There was no incidence of respiratory depression (<8 breaths/min) and no difference in sedation scores, antiemetic use, respiratory rate, and hemodynamic parameters among the groups. CONCLUSIONS: Naloxone is effective in preventing PCA opioid-related side effects. Naloxone infusion at 0.25 microg x kg(-1) x h(-1) not only attenuates these side effects but appears to reduce postoperative (beyond 4-8 h) opioid requirements. This dosing regimen can be prepared with 400 microg naloxone in 1,000 ml crystalloid given in 24 h to a patient weighing 70 kg.     

Pharmacokinetics of doxycycline in pigs following oral administration in feed

Doxycycline medicated feed was administered to healthy fattening pigs for an 8-day period either for 1 h every 12 h or ad libitum. The average dosage regimen ranged between 11.8 and 13.3 mg/kg/day. Doxycycline concentrations were determined in plasma, lung and nasal mucosa using a high performance liquid chromatography assay (HPLC). The agreement between the doxycycline HPLC assay and a bioassay was also assessed in plasma. Following the multiple medicated feed administration every 12 h, the plasma concentrations were best described by a one-compartmental model with first-order absorption. Steady-state plasma concentrations ranged between 0.7 and 1 microgram/mL. The mean accumulation factor and elimination half-life were, respectively, 1.8 +/- 0.4 and 5.9 +/- 1.0 h. Following ad libitum administration of medicated feed, steady-state plasma concentrations ranged between 0.9 and 1.5 micrograms/mL. At the end of the treatment, the doxycycline lung and nasal mucosa concentrations were 1.7 +/- 0.4 micrograms/g and 2.9 +/- 0.6 micrograms/g, respectively. These data validate the dosage regimen tested in order to control pig respiratory infections, provided that controlled clinical studies are confirmatory.     

Effect of the H2-antagonist cimetidine on the pharmacokinetics and pharmacodynamics of the H1-antagonists hydroxyzine and cetirizine in patients with chronic urticaria

BACKGROUND: Concomitant administration of an H1-receptor antagonist with an H2-receptor antagonist may enhance the wheal and flare suppression produced by the H1-antagonist. This synergism may be due, at least in part, to a pharmacokinetic effect. METHODS: In a randomized, double-blind, parallel-group study in 16 patients with chronic urticaria, we investigated the pharmacokinetics and suppressive effect on the histamine-induced wheal and flare of a single dose of hydroxyzine 25 mg or cetirizine 10 mg, given before and after treatment with cimetidine 600 mg every 12 hours for 10 days. RESULTS: When hydroxyzine was administered with cimetidine, the partial hydroxyzine area under the curve increased significantly (p < 0.05) to 303 +/- 92 ng/ml/hr from 227 +/- 77 ng/ml/hr after administration of hydroxyzine alone, and the concentration of cetirizine arising from hydroxyzine was lower. When hydroxyzine was given with cimetidine, wheal and flare suppression increased compared with when hydrozyzine was given alone, but the differences were not statistically significant (p > 0.05). When cetirizine was administered with cimetidine, the pharmacokinetics of cetirizine did not change significantly, and no enhancement of wheal and flare suppression was observed. CONCLUSIONS: In this study co-administration of hydroxyzine with cimetidine resulted in significantly increased serum hydroxyzine concentrations and increased wheal and flare suppression, thus confirming the rationale for a trial of concomitant administration of these medications in some patients with chronic urticaria unresponsive to treatment with an H1-antagonist alone. We found no therapeutic rationale for co-administration of cetirizine with cimetidine in urticaria treatment. These medications may be co-administered safely without fear of medication interaction.     

Modified oral ondansetron regimen for cyclophosphamide-induced emesis in lupus nephritis

OBJECTIVE: To evaluate the antiemetic efficacy of a modified regimen of oral ondansetron and dexamethasone in patients with lupus nephritis undergoing treatment with cyclophosphamide whose conventional antiemetic regimen had failed. DESIGN: A before-after prospective observational pilot project. SETTING: A federal research hospital. PATIENTS: Fourteen outpatients with lupus nephritis receiving intravenous cyclophosphamide 0.75-1.0 g/m2 had previously experienced chemotherapy-induced emetic events (vomiting or retching) while receiving a standard combination intravenous antiemetic regimen. The regimen consisted of four doses of thiethylperazine 10 mg and diphenhydramine 25 mg every 6 hours, and two doses of lorazepam 0.5 mg every 6 hours starting at 1 hour prior to cyclophosphamide. A subset of 8 patients previously completed a blinded study in which they received the intravenous formulation of ondansetron (4 doses of 4-16 mg q4h) administered orally beginning 30 minutes prior to the cyclophosphamide infusion. MAIN OUTCOME MEASURES: The number of emetic events and cost of drug administration were assessed for the modified ondansetron intervention and compared with those of the standard antiemetic regimen. The incidence of emetic events and visual analog nausea scores for the subset of eight patients were also evaluated. INTERVENTIONS: To account for the delayed onset of emesis associated with cyclophosphamide, patients received both ondansetron 8 mg orally every 4 hours (3 doses) and dexamethasone 10 mg orally (1 dose) beginning 4 hours after the cyclophosphamide infusion. This is different from the manufacturer's recommended dose schedule, in which ondansetron is administered prior to chemotherapy. RESULTS: No emetic events were observed following the administration of oral ondansetron/dexamethasone. The 95% confidence interval for the true rate of emesis was 0% to 19.3%. There was a significant difference in efficacy between ondansetron/dexamethasone and the triple antiemetic regimen (p < 0.0002). None of the patients experienced adverse effects while receiving the ondansetron/dexamethasone regimen. Cost comparisons (including admixture and nursing administration times) for standard combination therapy and oral ondansetron/dexamethasone were $109.09 and $70.24, respectively. No difference in emetic events or nausea ratings was observed between oral ondansetron/dexamethasone tablets and oral administration of ondansetron using the intravenous formula. CONCLUSIONS: This study suggests that a modified oral ondansetron/dexamethasone regimen is safe and efficacious, and costs less than alternative regimens to prevent cyclophosphamide-induced emesis in patients with lupus nephritis.     

The effect of trauma on the ocular penetration of intravenous ciprofloxacin

PURPOSE: To study the intraocular pharmacokinetics of intravenously administered ciprofloxacin following eye trauma. METHODS: Twenty-three New Zealand albino rabbits and 12 Yorkshire pigs each received a surgically induced scleral injury to the right eye. Following repair, each rabbit received a single 30-mg intravenous infusion of ciprofloxacin. Each pig received either two 200-mg doses or two 400-mg doses of intravenous ciprofloxacin given 12 hours apart. Vitreous and serum samples were harvested at 0.5, 1, 4, 6, and 12 hours after antibiotic administration in rabbits and 1 hour after the second dose in pigs. Bioassays for ciprofloxacin were performed on each sample, and results were statistically compared by t test. The untraumatized left eye in each animal served as a control. RESULTS: The mean vitreous concentration of ciprofloxacin in traumatized rabbit eyes was 0.37 microgram/ml. This level was sustained above levels in control eyes (0.18 microgram/ml) for at least 4 hours following antibiotic administration. In control eyes, intravitreal levels peaked at 1 hour. Mean vitreous concentrations +/- SD in traumatized pig eyes were 0.091 +/- 0.017 microgram/ml in swine that had received 200-mg doses of ciprofloxacin vs 0.312 +/- 0.153 microgram/ml in swine that had received 400-mg doses (P = .02). Mean vitreous concentrations of ciprofloxacin in control eyes were not affected by increasing dosage. CONCLUSION: In both animal models, experimental surgical trauma increased intravitreal ciprofloxacin delivery. In addition, systemically administered ciprofloxacin achieved intravitreous levels exceeding minimum inhibitory concentrations for common ocular pathogens, suggesting a role for ciprofloxacin in the prophylaxis of posttraumatic endophthalmitis.     

Clinical efficacy and safety of a novel controlled-release morphine suppository and subcutaneous morphine in cancer pain: a randomized evaluation

PURPOSE: A significant number of cancer patients will require an alternate route of morphine administration at some point during their illness. This study compared the clinical efficacy and safety of a novel morphine sulfate controlled-release suppository (MS-CRS) and subcutaneous (SC) morphine in patients with cancer pain. METHODS: Thirty patients with cancer pain were randomized in a double-blind crossover study to MS-CRS every 12 hours or SC morphine every 4 hours for 4 days each, using a 2.5:1 analgesic equivalence ratio. Pain intensity was assessed using a visual analog scale (VAS) and the Present Pain Intensity Index of the McGill Pain Questionnaire. Nausea and sedation were also assessed with a VAS. Evaluations were made by the patient at 8 AM, noon, 4 PM, and 8 PM and rescue morphine consumption recorded. RESULTS: Twenty-three patients completed the study (13 men and 10 women; mean age, 64.0 +/- 2.0 years) and were treated with mean daily MS-CRS and SC morphine doses of 326 +/- 69 mg and 138 +/- 28 mg, respectively. There was a small but significant difference in overall ordinal pain-intensity scores in favor of MS-CRS (0.7 +/- 0.1 v 0.9 +/- 0.1, P = .0459). There were no significant differences between MS-CRS and SC morphine in overall VAS scores for pain intensity (13 +/- 3 v 13 +/- 3 mm), sedation (23 +/- 3 v 25 +/- 4 mm), and nausea (8 +/- 2 v 9 +/- 2 mm). The mean daily rescue analgesic consumption during MS-CRS and SC morphine did not differ significantly (1.2 +/- 0.4 v 1.2 +/- 0.4 doses/d). CONCLUSION: MS-CRS, administered every 12 hours, provides analgesia comparable to SC morphine and represents a reliable, noninvasive alternative method of pain control for patients unable to take oral morphine.     

Pharmacokinetics of famotidine in patients with cystic fibrosis

Famotidine pharmacokinetics were studied in 13 patients with severe cystic fibrosis (CF) ranging from 10 to 47 years of age and 25 to 72 kg in weight. Patients were randomized to first receive famotidine either 20 mg intravenously or 40 mg orally. Twelve patients were crossed over to the alternate treatment. Repeated blood samples were obtained over 12 hours after intravenous and oral administration and urine was collected over 24 hours for quantitation of famotidine by means of high-performance liquid chromatography (HPLC). A compartment model-dependent approach was used to characterize the disposition of famotidine. From the intravenous data, the mean +/- standard deviation elimination half-life (t1/2) was 2.11 +/- 0.75 hours, the total clearance (Cl) was 0.79 +/- 0.41 L/kg/hr, the renal clearance was 0.57 +/- 0.26 L/kg/hr, the fraction eliminated unchanged in the urine was 83% +/- 16%, and the apparent volume of distribution (Vdss) was 1.33 +/- 0.53 L/kg. The bioavailability determined from comparison of intravenous and oral area under the curve data was 71% +/- 27%. Results of this study support an initial famotidine dose of 20 mg intravenously or 40 mg orally every 12 hours in patients with CF who are older than 9 years of age.     

Effect of high-dose oral ganciclovir on didanosine disposition in human immunodeficiency virus (HIV)-positive patients

This study was designed to investigate the interaction between high-dose oral ganciclovir (6,000 mg/day) and didanosine at steady state in patients who were seropositive for human immunodeficiency virus (HIV) and cytomegalovirus (CMV) infection. The study was conducted as an open-label, randomized, three-period crossover study. Patients received (in random order) multiple oral doses of didanosine 200 mg every 12 hours alone, ganciclovir 2,000 mg every 8 hours alone, and ganciclovir 2,000 mg every 8 hours in combination with didanosine 200 mg every 12 hours. Blood and urine samples for determinations of drug concentrations were obtained on day 3 of each dose regimen. When ganciclovir was administered either before or 2 hours after didanosine, the mean increases in maximum concentration (Cmax), area under the concentration-time curve (AUC0-12), and percent excreted in urine of didanosine were 58.6% and 87.3%, 87.3% and 124%, and 100% and 153%, respectively. There were no statistically significant effects of didanosine on the steady-state pharmacokinetics of ganciclovir in the presence of didanosine, irrespective of sequence of administration. There were no significant changes in renal clearance of didanosine, suggesting that the mechanism for the interaction does not involve competition for active renal tubular secretion. The mechanism responsible for increased didanosine concentrations and percent excreted in urine during concurrent ganciclovir therapy may be a result of increased bioavailability of didanosine. However, the mechanism appears to be saturated at oral ganciclovir doses of 3 g/day.     

Evaluation of the pharmacokinetic and pharmacodynamic interaction between quinidine and nifedipine

Quinidine and nifedipine appear to be subject to metabolism by the same isozyme of cytochrome P-450. In addition, both drugs have been reported to alter the pharmacokinetics of other compounds. To investigate a potential interaction, 10 healthy subjects (five male, five female) received quinidine sulfate (200 mg orally), nifedipine (20 mg orally), or the combination of both drugs every 8 hours for 4 doses using a randomized, cross-over study design with a 2-week washout period between treatments. Drug concentration, heart rate, and mean arterial pressure were measured at frequent intervals after the final dose. Quinidine concentrations were unchanged by the co-administration of nifedipine. Nifedipine area under the curve (AUC0-8) increased 36.6% from 333 to 455 micrograms.hr/L (P < .05) after quinidine administration. Heart rate was significantly higher in the nifedipine-quinidine treatment at 0.5, 1.0, 1.5, and 2.0 hours when compared with either drug alone. The maximum increase in heart rate (17.9 beats/minute) occurred at 0.5 hours after nifedipine administration and was significantly correlated with serum concentrations at that time (r = .78). These results suggest that quinidine inhibits nifedipine metabolism, and this pharmacokinetic interaction results in enhanced pharmacologic response.     

Measurement of pulmonary status and surfactant protein levels during dexamethasone treatment of neonatal respiratory distress syndrome

PURPOSE: To study the effect of epidural buprenorphine on minimum alveolar concentration (MAC) of volatile anaesthetics, duration of analgesia and respiratory function in the perioperative period. METHODS: One hundred and twenty patients, ASA I-II undergoing gynaecological surgery were randomly divided into three studies. The forty patients in each study were randomly divided into four groups depending on the dosage; Group I (control), Group II (80 micrograms. kg-1 morphine), Group III (4 micrograms. kg-1 buprenorphine), Group IV (8 micrograms. kg-1 buprenorphine). The MAC of halothane was measured following epidural administration of the agents in each group. The duration of analgesia was assessed by the first request for pentazocine. Postoperative analgesic effects were assessed by the total dosage of pentazocine required for the 48 hr after surgery. Respiratory rate (RR), minute volume (MV), and PaCO2 were measured during surgery and the postoperative period. The MAC of halothane was reduced in Group IV (P < 0.01). The duration of analgesia was 10.0 +/- 5.1 hr (Mean +/- SE) in Group I, 37.7 +/- 4.7 hr in Group II, 27.1 +/- 7.1 hr in Group III, and 44.4 +/- 4.1 hr in Group IV. Total dosage of pentazocine was lower in Group IV (P < 0.05) than in the other groups. The decrease of RR, MV and the increase of PaCO2 were observed within 60 min in Group III and IV dose dependently. CONCLUSION: Epidural buprenorphine administered in a dose of 4 or 8 micrograms. kg-1 provides postoperative analgesia that is no less effective than that of morphine.     

Assessment of ventricular diastolic function in AIDS patients from Congo: a Doppler echocardiographic study

The aim of this study was to evaluate the effect of transdermal clonidine on hemodynamic and metabolic parameters in patients who have elevated blood pressure and non-insulin-dependent diabetes mellitus (NIDDM). After a 2-week run in placebo period, 20 NIDDM patients who had diastolic blood pressure in the range of 90 to 105 mm Hg underwent a randomized, single blind, placebo controlled, cross-over study of 4 week treatment with clonidine (transdermal patch 2.5 mg/week) or placebo (inactive patch). Compared with placebo, clonidine significantly reduced systolic (153 +/- 6 v 163 +/- 8) and diastolic (88 +/- 2 v 98 +/- 3.5 mm Hg, P = .001) blood pressure, left ventricular mass (94 +/- 11 v 99 +/- 12 g/m2, P < .01) and fasting glucose levels. Total glucose disposal (glucose clamp) was 6.5 +/- 1.5 with placebo and 7.1 +/- 1.6 mg/kg/min with clonidine (P < .01). Oxidative glucose disposal (indirect calorimetry) was also greater after clonidine. Plasma glucose, insulin, and C-peptide responses following oral glucose (75 g) were significantly lower after clonidine, as well as urinary albumin excretion. Transdermal clonidine is effective in reducing blood pressure in hypertensive NIDDM patients and is well tolerated. It may be useful to reduce the cardiovascular impact of hypertension in diabetes mellitus.     

The pharmacokinetics and pharmacodynamics of the oral iron chelator deferiprone (L1) in relation to hemoglobin levels

Recently, we demonstrated that administration of the orally active iron chelating agent deferiprone (1,2-dimethyl-3-hydroxypyrid-4-one (L1)) at 6-hour intervals results in significantly greater urinary iron excretion than that induced during administration of the drug at 12-hour intervals. That study was conducted in thalassemia patients, all of whom had received a packed red cell transfusion of 15 cc/kg. 72 hours prior to evaluation of urinary iron excretion, at a time when endogenous erythropoiesis would be expected to be at its lowest. In clinical practice however, thalassemia patients, suppression of endogenous erythropoiesis is not sustained between transfusions. We set out to determine the influence that administration of deferiprone has on urinary iron excretion at lower hemoglobin concentrations, immediately prior to transfusion. We hypothesized that hemoglobin levels will affect the ability of deferiprone to chelate iron. Ten regularly transfused patients with homozygous beta-thalassemia (HBT) aged mean +/- SD, 20.9 +/- 4.7, range 13 - 27 years, receiving long-term therapy with deferiprone, were treated with deferiprone 75 mg/kg/day, administered every 6 hours (or every 12 hours) for 72 hours immediately prior to a blood transfusion in the first month. One month later each patient received the other of the 2 dosing regimens for 72 hours immediately prior to transfusion. The deferiprone-induced 24-hour urinary iron excretion was similar during both dosing regimens; 0.56 +/- 0.45 mg/kg when L1 was given every 6 hours and 0.48 +/- 0.52 mg/kg when L1 was administered every 12 hours (p = 0.79). However, the calculated 24-hour area under the plasma concentration-time curve (AUC0-24) of deferiprone was significantly lower when deferiprone was administered at 6-hour intervals (6,762.8 +/- 1,601.6 mg*min/l), than that observed when deferiprone was administered every 12 hours (8,250.1 +/- 1,235.7 mg*min/l) (p = 0.04). The pharmacokinetics of deferiprone when administered immediately prior to transfusions are different from those following transfusions. More studies assessing total body iron excretion are needed to determine the contribution of the fecal route in iron excretion.     

Determination of plasma digoxin in newborn infants. Practical applications

Measurement of plasma digoxin concentrations in infants after three increasing dosage levels shows that the optimal dose of this glycoside in 20 microgram/kg/day, i.e. a loading dose of 20 microgram/kg followed every 8 hours by a maintenance dose of 7 microgram/kg. The plateau concentration achieved is 3.0 +/- 0,5 ng/ml 8 hours after the last administration. When digoxin levels exceed 5 ng/ml (overdosage, renal failure or low body weight), toxic manifestations occur.     

Recombinant tumor necrosis factor for superficial bladder tumors

Twenty patients with histologically documented superficial bladder cancer (Ta, T1, Tis) were treated with intravesical administration of TNF 400-1800 micrograms. Of 18 patients with a marker lesion, 2 obtained a complete response for 8+ and 18 months. Two had a partial response and were given other intravesical therapies after 5 and 7 months. No or minimal systemic absorption of TNF was observed and documented in 4 of 20 patients by pharmacokinetic studies, and no patients developed antibodies to intravesically administered TNF. TNF was well tolerated in doses up to 1800 micrograms. No systemic or local side effects were observed. Modest activity was attained with intravesical TNF, even in pretreated patients.     

Evaluation of the effect of fluconazole on the pharmacokinetics of ritonavir

The effects of fluconazole on the pharmacokinetics of the HIV protease inhibitor ritonavir were investigated after multiple dosing in an open-label study. In this randomized, two-period crossover study, eight healthy subjects received ritonavir alone (200 mg every 6 hr for 4 days) and ritonavir with fluconazole (400 mg on day 1, 200 mg every day on days 2-5) with a 2-week washout period. Ritonavir plasma concentrations were measured during the final four ritonavir dosing intervals (24 hr) and a 12-hr washout period. There were statistically significant increases in ritonavir C(max) and AUC0-24 (p < 0.02), with concurrent administration of fluconazole compared with administration of ritonavir alone. The difference between regimens in C(min) was marginally statistically significant (p = 0.089), and t(max) and beta were not statistically significantly different. Although some ritonavir parameters were affected by fluconazole, mean increases in C(max) and AUC were < or = 15% for the 24-hr period, and only 7-19% for individual dose intervals. Thus, the pharmacokinetics of ritonavir may be influenced only to a small extent when administered with fluconazole. These changes are probably of limited clinical significance and do not necessitate dosage adjustment of ritonavir when fluconazole is added to the regimen.     

Heparan sulfate: its kinetic effects on fibrinolytic-coagulative parameters after oral administration]

The effects of the oral administration of 100 or 200 mg of heparan sulphate or placebo over time were assessed in nine healthy volunteers. Blood samples were collected at 1, 2, 4, 6, 8 and 12 hours after administration to assay prothrombin activity, partially activated thromboplastin time, and the activation to tPA and PAI-1. A significant increase (P < 0.001) of tPA activity and a reduced inhibition of fibrinolytic systems by PAI-1 were observed. These effects, which were clearly dose-dependent, appeared 2 hours after administration and persisted for 6-8 hours. On the contrary, no changes were recorded in coagulative tests at the doses used.