Chronopharmacological study of furosemide in rats

Improving Diuretic Response in Heart Failure by Implementing a Patient-Tailored Variability and Chronotherapy-Guided Algorithm

Heart failure is a major public health problem, which is associated with significant mortality, morbidity, and healthcare expenditures. A substantial amount of the morbidity is attributed to volume overload, for which loop diuretics are a mandatory treatment. However, the variability in response to diuretics and development of diuretic resistance adversely affect the clinical outcomes. Morevoer, there exists a marked intra- and inter-patient variability in response to diuretics that affects the clinical course and related adverse outcomes. In the present article, we review the mechanisms underlying the development of diuretic resistance. The role of the autonomic nervous system and chronobiology in the pathogenesis of congestive heart failure and response to therapy are also discussed. Establishing a novel model for overcoming diuretic resistance is presented based on a patient-tailored variability and chronotherapy-guided machine learning algorithm that comprises clinical, laboratory, and sensor-derived inputs, including inputs from pulmonary artery measurements. Inter- and intra-patient signatures of variabilities, alterations of biological clock, and autonomic nervous system responses are embedded into the algorithm; thus, it may enable a tailored dose regimen in a continuous manner that accommodates the highly dynamic complex system.

Circadian changes in the pharmacokinetics and pharmacodynamics of azosemide in rats

The circadian changes in the pharmacokinetics and pharmacodynamics of azosemide were investigated after intravenous and oral administration of the drug (10 mg kg(-1)) to rats at 1000 or 2200 h. After intravenous administration of azosemide the percentage of the dose excreted in 8-h urine as unchanged azosemide was significantly higher in the 1000 h group than in the 2200 h group (41.7 compared with 28.9%) and this resulted in a significant increase in 8-h urine output (84.7 compared with 36.6 mL/100 g). After intravenous administration the time-averaged renal clearance (CLR) of azosemide was significantly faster (2.86 compared with 1.76 mL min(-1) kg(-1)) and urinary excretion of sodium (46.4 compared with 25.9 mmol/100 g) and chloride (35.6 compared with 18.8 mmol/100 g) increased significantly in the 1000 h group. However, after oral administration, the percentages of oral dose of azosemide excreted in 8-h urine as unchanged azosemide were significantly higher (1.88 compared with 0.67%) and the CL(R) of azosemide was significantly faster (3.64 compared with 0.79 mL min(-1) kg(-1)) in the 2200 h group. This could be at least partly because of increased absorption of azosemide from the gastrointestinal tract in the 2200 h group; the percentages of oral dose of azosemide recovered from the gastrointestinal tract in 8 h as unchanged azosemide was significantly smaller (5.7 compared with 13.2%) in the 2200 h group. The pharmacodynamic parameters of azosemide were not significantly different after oral administration of the drug to both groups of rats. If these data could be extrapolated to man, the intravenous dose of azosemide could be modified on the basis of circadian time.

Circadian variation in urinary excretion of ciprofloxacin after a single-dose oral administration at 1000 and 2200 hours in human subjects

Ciprofloxacin is routinely prescribed to treat a variety of infections, including those of the urinary tract. To achieve optimum therapeutic benefits of the drug, all of the factors which influence its pharmacokinetics and effectiveness need to be determined. This study investigated the urinary excretion kinetics of ciprofloxacin upon oral administration of a single dose of 250 mg at 1000 or 2200 h in 12 healthy human subjects in a crossover design. The urine samples were analyzed for unchanged ciprofloxacin by a sensitive high-performance liquid chromatography method. A significant decrease in the rate and extent of ciprofloxacin excretion following 2200 h (109.59 versus 53.8 mg [P < 0.05]) administration was observed. This result may be due to circadian changes in the factors affecting renal excretion and also probably metabolism of ciprofloxacin.

Time-dependent change in the toxic effects of amikacin on renal functions

The present study was undertaken to examine whether there was a time-dependent change in the toxic effects of amikacin, an aminoglycoside, on renal functions. Male Wistar rats were maintained under conditions of light from 7 am to 7 pm and dark from 7 pm to 7 am. Amikacin (1.2 g/kg) was injected intraperitoneally to animals at 4 am, 10 am, 4 pm or 10 pm. Glomerular function estimated by creatinine clearance (Clcr) and tubular function estimated by urinary excretion of a loop diuretic, furosemide, which was excreted in urine mainly by tubular secretion, were determined before and 24 hours after amikacin injection. The values of these parameters were reduced by amikacin at each observation point. The magnitude of these decrements was greatest at 4 pm both for Clcr and urinary furosemide excretion. These results suggest that the toxic effects of amikacin on renal glomerular and tubular functions vary with its time of administration.

Effects of heparin on the inhibitory activities of human urinary trypsin inhibitor (ulinastatin) on trypsin, chymotrypsin and leukocyte elastase

Effects of heparin on the inhibitory activities of human urinary trypsin inhibitor (ulinastatin) on trypsin, chymotrypsin and leukocyte elastase were studied. Heparin per se neither influenced the enzymatic activities nor changed the mode of inhibition of ulinastatin on the enzymes. In the presence of heparin, inhibitory effects of ulinastatin on trypsin were enhanced, whereas its effects on chymotrypsin and elastase were attenuated. These results suggest that the two functional domains in ulinastatin are differently affected by heparin.

Influence of clorgyline treatment on chronopharmacology of furosemide in rats

Circadian variations in the adrenergic nervous system have been reported to be altered by chronic treatment with clorgyline, a monoamine-oxidase inhibitor. In the present study, the influence of clorgyline on the chronopharmacology of furosemide, a loop diuretic agent, was examined in rats maintained under conditions of light from 7 am to 7 pm and dark from 7 pm to 7 am. Clorgyline (4 mg/kg/day) or its vehicle alone was infused subcutaneously by osmotic minipumps for 14 days. Furosemide (30 mg/kg) was given orally at 12 am [noon (N)] or 12 pm [midnight (M)]. Urine was collected for 8 hours after the agent, and urinary excretions of sodium and furosemide were determined. Urine volume and urinary excretions of sodium and furosemide were significantly greater at 12 N than at 12 M in the vehicle-infused group of rats. However these administration time-dependent changes in the effects of furosemide and its urinary excretion disappeared in the clorgyline-infused animals. These results suggest that the mode of the diurnal variation in the effects of furosemide is altered by chronic treatment with clorgyline. As chronic clorgyline is considered to disturb the adrenergic nervous system, the present findings are compatible with the hypothesis that this system is involved in the mechanism responsible for the time-dependent change in the effects of furosemide.

Chronopharmacology of furosemide in the elderly

The authors have previously reported the time-dependent change in the diuretic effects of furosemide, a loop diuretic agent, in young and middle-aged subjects. The current study was undertaken to examine an influence of aging on this chronopharmacologic phenomenon. Ten milligrams furosemide was given intravenously to 12 elderly subjects (greater than 70 years of age) at 9:00 AM (day trial) or at 9:00 PM (night trial) by a cross-over design. One-hour urine samples were collected for 3 hours after each administration, and urine volume and urinary excretions of sodium and furosemide were determined. Urine volume and urinary sodium excretion increased after furosemide administration. Contrary to the findings in the young and middle-aged subjects, no significant differences were observed in these parameters at any observation period between the day and night trials in the elderly subjects. Urinary furosemide excretion of the day and night trials did not significantly differ. These results suggest that the chronopharmacologic profiles of furosemide are altered in the elderly.

Influence of DOCA treatment on administration-time-dependent changes in the effects of furosemide in saline-loaded rats

We have previously found that the administration-time-dependent change in the effects of furosemide, a loop diuretic agent, is observed in normal rats. The present study was undertaken to examine whether an alteration in this phenomenon occurs in rats with DOCA-saline hypertension. Unilateral nephrectomized rats were divided into three groups. The first group (DOCA-saline) received a 50 mg DOCA tablet intraperitoneally and drank 1% NaCl solution. The other two groups were given sham operations. A 1% NaCl solution was given as drinking water to the second group (control-saline), while tap water was given to the third group (control-water). Furosemide (30 mg/kg) was given orally to each group at 12 a.m. or 12 p.m. Urine was collected for 8 hours after the agent, and urinary excretion of sodium and furosemide were determined. Urine volume and urinary excretion of sodium and furosemide following the agent were significantly greater at 12 a.m. than at 12 p.m. in the control-water and control-saline groups. However, the administration-time-dependent changes in these parameters disappeared in the DOCA-saline rats. These results suggest that the mode of the administration-time-dependent changes in the effects of furosemide is altered in the DOCA-saline hypertensive rats.

Influence of renal denervation on chronopharmacology of furosemide in rats

Our previous studies have suggested that the adrenergic nervous system is involved in the mechanism responsible for the time-dependent change in the urinary excretion of furosemide in rats. To examine a potential role of renal nerves in this phenomenon, renal denervation or sham operation was performed using unilaterally nephrectomized rats. Furosemide (30 mg/kg) was given orally at 12 am or 12 pm. Urine was collected for 8 hours after furosemide dosing, and urinary excretions of furosemide and sodium were determined. Urinary furosemide excretion and diuretic effects of the agent (urine volume and urinary sodium) were significantly greater at 12 am than at 12 pm in the sham-operated group of rats. However these administration time-dependent changes in urinary furosemide and its diuretic effects disappeared in the renal-denervated group of animals. These results suggest that the renal nerves contribute to the time-dependent changes in the urinary excretion of furosemide and its subsequent diuretic effects.

Chronopharmacological study of furosemide; (IX). Influence of continuous norepinephrine infusion

Our previous studies have suggested that the adrenergic nervous system is involved in the mechanisms responsible for the time-dependent changes in the effects of furosemide in rats. To examine this hypothesis further, norepinephrine (150 micrograms/kg/hr) or its vehicle alone was infused subcutaneously by osmotic minipumps. Furosemide (30 mg/kg) was given orally at 12 am or 12 pm. Urine was collected for 8 hours after the agent, and urinary excretions of sodium and furosemide were determined. Urine volume and urinary excretion of sodium and furosemide were significantly greater at 12 am than at 12 pm in the vehicle-infused group of rats. However these administration-time-dependent changes in the effects of furosemide and its urinary amount disappeared in the norepinephrine-infused group of animals. Since chronic norepinephrine infusion is considered to disturb the axis of adrenergic nervous system, these data support the hypothesis concerning the mechanisms of this chronopharmacological phenomenon of furosemide.

Chronotherapy of trichlormethiazide in hypertensive patients

Circadian influence of trichlormethiazide on serum electrolyte levels, lipid levels, and glucose levels were evaluated in 12 hypertensive patients. One tablet of trichlormethiazide (2 mg) was given once a day at 7:00 AM or 7:00 PM for 8 weeks. The study was done by a crossover design. Twenty-four-hour urine was collected, and fasting blood samples were obtained during the control period and at the end of each treatment period. The 24-hour urine level increased slightly after treatment with trichlormethiazide in the morning and evening trials. Urinary excretion of sodium also increased slightly in the morning trial and increased significantly in the evening trial. Serum concentrations of potassium and chloride decreased, and serum uric acid level increased after trichlor-methiazide treatment. No significant difference was observed in these parameters between morning and evening trials. Fasting blood glucose levels increased after trichlormethiazide treatment. The increment in blood glucose levels was greater in the evening trial than in the morning trial. These data indicate that the influence of trichlormethiazide on glucose tolerance might vary with its administration time.

Circadian influence on effect of propranolol on exercise-induced tachycardia in healthy subjects

Following a cross-over design propranolol 20 mg p.o. was given to 7 healthy subjects at 09.00 h and 21.00 h at an interval of 1 week. Heart rate (HR) during submaximal ergometer exercise was measured at four intervals during 10 h after treatment. Plasma propranolol concentrations were also determined. The suppressive effect (%R) of propranolol on the rise in HR during exercise after the morning dosage was significantly greater at 1.5 h and tended to be greater 3 h after administration than at comparable times in the evening trial. Mean plasma propranolol concentrations during the early phase were higher after the morning than the evening dose. The maximum plasma concentration (Cmax), area under the plasma concentration-time curve from 0 to 10 h (AUC (0-10] and absorption rate constant (ka) were significantly greater after the morning dose. The time to maximum concentration (tmax) and elimination half-life (t 1/2) of the morning and evening dosages did not differ. A significant correlation was observed between plasma propranolol concentration and %R in HR during exercise in the morning (r = 0.74) and evening (r = 0.63) trials, and the regression lines of the morning and evening treatments did not differ.(ABSTRACT TRUNCATED AT 250 WORDS)

Chronopharmacological study of furosemide; (V). Influence of pretreatment with 6-hydroxydopamine

Our previous indirect evidences suggested that the adrenergic nervous system is involved in the mechanisms responsible for the time-dependent changes in the effects of furosemide in Wistar rats. In the present study, the role of this system was examined more directly by means of 6-hydroxydopamine-induced sympathectomy. Thirty mg/kg of 6-hydroxydopamine hydrobromide (6-OH-DA) (n = 9) or its vehicle alone (n = 9) was injected intra-arterially (i.a.) twice in Wistar rats. Furosemide (5 mg/kg) was administered i.a. at 1000 hrs (03HALO*) or at 2200 hrs (15HALO). Urine was collected for 60 min after the drug and urinary excretion of sodium and furosemide were determined respectively. Urine volume and urinary excretion of sodium and furosemide were significantly greater at 1000 hrs (03HALO) than at 2200 hrs (15HALO) in the vehicle-injected rats as observed in the previous study. However these administration-time-dependent changes in the effects of furosemide disappeared in the rats with 6-OH-DA. Thus, the present study provides more direct evidence and supports our original hypothesis concerning the mechanisms of this chronopharmacological phenomenon of the agent. Since 6-OH-DA does not penetrate the central nervous system from the blood stream, the present data also indicate that the peripheral adrenergic system is involved in this event.

Chronopharmacological study of furosemide; (VII). Influence of repeated administration on biochemical parameters in blood

The present study was undertaken to examine whether influences of furosemide on biochemical parameters vary with its time of administration in Wistar rats. Rats were maintained under conditions of light (0700-1900 hrs) and dark (1900-0700 hrs). Furosemide (30 mg/kg) or vehicle (5% glucose) was given orally at 1000 hrs (day trial) or at 2200 hrs (night trial) for 14 days. Water and food intakes were measured, and urine was collected for 24 hours following the final dosage in each group. Thereafter, blood samples were obtained. Water intake and urinary excretions of volume, sodium and chloride increased by furosemide treatment. The increments in these parameters were greater in the day trial than in the night trial. Food intake did not change. The serum concentration of chloride was decreased by furosemide. The decrement in this parameter was enhanced in the day trial. The influence of furosemide on other biochemical parameters (sodium, potassium, creatinine, calcium, inorganic phosphate, total protein, total cholesterol and glucose) did not differ between the day and night trials. These data indicate that the untoward influence of furosemide on serum chloride might vary with its time of administration.

Chronopharmacological study of furosemide; (IV). Examination in aged rats

We have previously reported that a time-dependent variability is observed in the diuretic effects of furosemide in young Wistar rats. The present study was undertaken to examine the influence of ageing on chronopharmacological profiles of furosemide in rats. Furosemide (5 mg/kg) was injected intra-arterially in young (10-11 week old) and aged (21-22 month old) Wistar rats at 1000 hrs or at 2200 hrs. Urine was collected for 60 min after the drug and urinary excretion of sodium and furosemide were determined respectively. Urine volume and urinary excretion of sodium and furosemide following the drug injection were significantly greater at 1000 hrs than at 2200 hrs in the young rats as observed in the previous study. However these administration time-dependent changes in the effects of furosemide and its urinary amount disappeared in the aged rats. These findings indicate that the mode of the time-dependent changes in the effects of furosemide is altered in aged Wistar rats.

Chronopharmacological study of furosemide; (VI). Influence of prolonged exposure to continuous light

We have previously reported that a time-dependent variability is observed in the diuretic effects of furosemide in rats. The present study was undertaken to examine the influence of prolonged exposure to continuous light on chronopharmacological profiles of furosemide in Wistar rats. In study I, rats were maintained for more than 2 weeks under conditions of light (0700-1900 hrs) and dark (1900-0700 hrs) (L-D). Furosemide (30 mg/kg) was orally given at 1200 hrs or at 2400 hrs. Urine was collected for 8 hours after the drug and urinary excretion of sodium and furosemide were determined respectively. Thereafter, these rats were exposed to continuous light (L-L) for the next 4 weeks, and were again maintained under the L-D cycle. The identical trial of study I was repeated at the end of the L-L (study II) and the second L-D (study III) conditions. Urine volume and urinary excretion of sodium and furosemide following the drug were significantly greater at 1200 hrs than at 2400 hrs under conditions of L-D (study I and III). However these administration time-dependent changes in the effects of furosemide and its urinary amount disappeared with L-L condition (study II). These findings indicate that the mode of the time-dependent changes in the effects of furosemide is altered by prolonged exposure to continuous light.

Chronopharmacological study of nitrendipine in healthy subjects

Nitrendipine 20 mg or placebo was given orally to eight healthy subjects in a cross-over design separated by 1 or 2 weeks. Drug was given at 9:00 AM (morning dosage) or at 9:00 PM (evening dosage). Systolic and diastolic blood pressure (SBP, DBP) were measured just before and 1, 2, 3, 4, 5, 7, 9, 12 and 24 hrs after treatment. Plasma nitrendipine concentrations were determined at 0.5, 1, 2, 3, 4, 5, 7, 9, 12 and 24 hrs and plasma catecholamines were measured at 2 and 5 hrs following drug administration. SBP did not decrease significantly after nitrendipine compared to after placebo at 9:00 AM or at 9:00 PM. DBP decreased significantly at 2, 3, 4 and 5 hrs after nitrendipine at 9:00 AM, but only at 4 hours after the 9:00 PM dose. Mean plasma nitrendipine concentrations during the absorption phase were lower after the evening dosage compared to the morning interval. Maximum plasma concentration (Cmax) was significantly lower and time to maximum concentration (tmax) tended to be longer after the evening dosage. Area under the plasma concentration-time curve from 0 to 24 hours (AUC0-24) and half-life of the terminal elimination phase (t1/2 beta) of the morning and evening dosages did not differ. A significant correlation was observed between plasma nitrendipine concentrations and changes in DBP during the drug treatment. Plasma noradrenaline concentrations were significantly higher 5 hours after nitrendipine compared to after placebo at 9:00 AM, but not at 9:00 PM.(ABSTRACT TRUNCATED AT 250 WORDS)

Chronopharmacokinetic studies of pranoprofen and procainamide

There is increasing evidence demonstrating that plasma drug concentrations are affected by their time of administration. In the current study, the chronopharmacokinetic profiles of an antipyretic agent, pranoprofen, and an antiarrhythmic agent, procainamide, were examined. In the first study, 75 mg of pranoprofen was given orally in seven healthy subjects at 10:00 (morning trial) or 22:00 (evening trial). In the second study, 500 mg of procainamide was given orally in eight subjects with premature ventricular contractions at 10:00 or 22:00. Blood samples for plasma drug concentrations were taken for a 10-hour (pranoprofen study) or a 24-hour (procainamide study) post-drug period. In the first (pranoprofen) study, the mean time to maximum concentration was significantly shorter, and the mean maximum plasma concentration as well as absorption rate constant had a tendency to be greater after the morning than after the evening trial. The mean area under the plasma concentration-time curve, elimination half-life or oral clearance of the morning and evening dosages did not differ. In the second (procainamide) study, no significant difference was observed in any pharmacokinetic parameter concerning procainamide or its active metabolite, N-acetyl-procainamide (NAPA) between the morning and evening trials. These data indicate that plasma levels of pranoprofen are affected by its administration time while plasma concentrations of procainamide and NAPA do not vary with the time of dosage.

Chronopharmacological study of furosemide in rats: (III). Examination in spontaneously hypertensive and Wistar-Kyoto rats

We have previously reported that a time-dependent variability is observed in the diuretic effect of furosemide in Wistar rats and the adrenergic system is involved in the mechanisms responsible for this phenomenon. The present study was undertaken to examine chronopharmacological profiles of furosemide in two related but different strains of Wistar rats, spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats. Furosemide (5 mg/kg) was administered intra-arterially in SHR and WKY at 1000 hrs (03HALO) or at 2200 hrs (15HALO). Urine was collected for 60 min after the drug and urinary excretion of sodium and furosemide were determined respectively. In both groups of rats, urine volume and urinary excretion of sodium and furosemide were significantly greater at 1000 hrs (03HALO) than at 2200 hrs (15HALO) as observed in the previous study using Wistar rats. The diuretic effects of furosemide in SHR was not different from those in WKY at 1000 hrs (03HALO) or at 2200 hrs (15HALO). These data indicate that the effects of furosemide also vary with a time of administration in SHR and WKY as observed in Wistar rats. In addition, the present study suggest that the mode of the time-dependent changes in the effects of furosemide in SHR, which is reported to have an altered circadian rhythm in the adrenergic system, does not differ from that in WKY rat.

A quantitative method of evaluating the diuretic response to furosemide in rats

Furosemide effects are usually evaluated by measuring the urinary excretion rate of Na+ (UVNa) in humans. In the present study, however, UVNa showed a nonlinear relationship with urine flow rate after intravenous injection of furosemide in rats. In contrast, when the urinary excretion rate of (Na+ + K+) (UVNa + K) was plotted against the urine flow rate, a linear regression line was observed, with small interindividual variations in normal rats and in rats with uranyl nitrate-induced acute renal failure (ARF). Piretanide, a loop diuretic, also showed a similar relationship, while other types of diuretics revealed different slope values for the relationship. Although the urinary excretion rate of Cl- (UVCl) vs UVNa + K is expected to show a linear relationship in normal rats, the correlation coefficient of the linear regression line was smaller than that of the urine flow rate vs UVNa + K. Further, the slope of UVCl vs UVNa + K was slightly different in ARF rats. Therefore, UVNa + K provides a better quantitative measure of diuretic response to loop diuretics than UVNa or UVCl.

Chronopharmacological study of furosemide in rats: (II). Influence of beta-adrenoceptor blockade

We have previously demonstrated a time-dependent variability in the diuretic effect of furosemide in rats. The present study was undertaken to evaluate the influence of beta-adrenoceptor blockade on these time-dependent variations. Furosemide (5 mg/kg) was administered intra-arterially in Wistar rats at 1000 hrs (03HALO) or at 2200 hrs (15HALO) with pretreatment with either propranolol (10 mg/kg) or atenolol (10 mg/kg). Urine was collected for 60 min after furosemide administration and urinary excretion of sodium and furosemide were determined respectively. Propranolol pretreatment abolished the temporal variations observed in urine volume, urinary sodium and furosemide levels during the observation periods. With atenolol pretreatment, however, all these variables were significantly greater at 1000 hrs (03HALO) than at 2200 hrs (15HALO) as observed in the previous study. These results suggest that the beta-adrenoceptor-mediated stimuli, which is blocked by propranolol but not by atenolol, is responsible for the time-dependent changes in the diuretic effect of furosemide.