Subject serum concentration

Following a single oral dose of 10 mg/kg to 5 subjects, serum concentrations of 0.30 to 0.68 ig/ml (mean 0.5) were reported after 4 hours the ratio of erythrocyte to serum concentration varied with time and between individuals, but erythrocyte concentrations were generally higher than serum concentrations after 48 hours (G. M. Trenholmee/ al., ibid.). 

After oral doses of 100 mg three times a day to 9 subjects, serum concentrations of 20 to 98 pg/ml (mean 49) were reported on the 8th day (J. H. Baron et al.. Factors affecting the Absorption of Carbenoxolone in Patients with Peptic Ulcer, in 4th Symposium on Carbenoxolone, F. A. Jones and D. V. Parke (Ed.), London, Butterworths, 1975, pp. 115-124). 

Following single intravenous injections of 2.5 mg/kg to 5 subjects, serum concentrations of about I pg/ml were reported after 15 minutes (J. Wieber et al., Anaesthesist, 1975, 24, 260-263). 

Following daily oral doses of 3 to 14.5 mg/kg to 36 subjects, serum concentrations ranged from 0.5 to 12.5 ig/ml peak concentrations were attained 1 to 5 hours after a dose (O. V. Olesen, Actapharmac. tox., 1968, 26, 22-28). 

Oxolonic acid is in vitro more efficient than nalidixic acid. The therapeutic mechanism is in this case too thought to be inhibition of bacterial DNA synthesis. The optimal action is in the range of pH 6.5-8. The half-life in serum is 2 /2-3 h. After oral administration of 4 x 240 mg oxolonic acid to human subjects, serum concentrations of 1.8 pg/ml and average 24-h-urine concentrations of 40 pg/ml are reached. 

In the same 15 euthyroid subjects, serum concentrations of PBl, T3 uptake and iodothyronines, and degradation rates of thyroxine were all within the normal range and Fig.5 shows the comparison between the thyroidal absolute iodine uptake and the degradation of thyroxine. The results are essentially the same as in rat thyroids and this balance is a good example of autoregulalion. 

There is limited information available regarding the distribution of methyl parathion after dermal exposure in humans. Two subjects, dermally exposed to methyl parathion, had 2.74 and 1.23 mg on their hands. Twenty-four hours after exposure, the serum levels were 0.027 and 0.032 mg/L, respectively (Ware et al. 1973). Twelve hours after cotton fields were sprayed, five men entered the treated fields for 5 hours. An average of 1.7 mg methyl parathion was detected on their hands. Serum concentrations averaged 0.156 mg/L in these subjects after 3 hours of exposure. Levels decreased to 0.1 and 0.002 mg/L at 2 and 24 hours postexposure, respectively (Ware et al. 1975). Although 0.5 mg methyl parathion was detected on the hands of four subjects, none was found in the serum (Ware et al. 1974). No information on the tissue distribution of methyl parathion in humans was found. 

In a 20-week multicenter intervention trial with lutein in healthy human subjects, no changes were noted in hematological or biochemical parameters after continuous daily lutein doses of 15 mg (0.25 mg/kg body weight, assuming a body weight of 60 kg). A relatively large number of human studies have examined correlations between macular degeneration and dietary intake of lutein or zeaxanthin, intakes via dietary supplements, and serum concentrations. 

Fig. 17 (A) Demeclocycline serum concentrations as a function of time in four to six subjects after oral ingestion of deme-...

Olmedilla B, Granado F, Southon S, Wright AJA, Blanco I, Gil-Martinez E, Berg H, Corridan B, Roussel AM, Chopra M and Thurnham DI. 2001. Serum concentrations of carotenoids and vitamins A, E, and C in control subjects from five European countries. British J Nutr 85(2) 227-238. 

Deaths directly attributable to LSD have not been documented. A suspected case occurred in a 34-year-old man who had been known to act strangely on occasion and who was later found dead. Postmortem examination revealed no anatomic cause of death, but the liver showed extremely high concentrations of LSD (23). Hyperthermia, coma, and respiratory arrest were found among eight users who had snorted an unusually large amount of LSD serum concentrations ranged from 2 to 26 ng/ml in these patients (3). These complications, as well as seizures, which have been reported in other cases of overdose, could produce death in an unattended subject. 

Ofloxacin - Maximum serum concentrations are achieved 1 to 2 hours after an oral dose. Steady-state concentrations are achieved after 4 doses. Ofloxacin is widely distributed to body tissues and fluids. Elimination is mainly by renal excretion 4% to 8% is excreted in the feces. A longer plasma half-life of about 6.4 to 7.4 hours was observed in elderly subjects, compared with 4 to 5 hours for young subjects. Dosage adjustment is necessary for patients with impaired renal function (Ccr 50 mL/min or less). 

Distribution - Peak serum concentrations following IM administration of 1 g are achieved in 1 to 2 hours. Low serum concentrations are present at 24 hours. Doses of 1 g daily for 30 days or longer produce no significant accumulation in subjects with normal renal function. 

Cohen et al. (1999) reported an absence of a clinically significant pharmacokinetic interaction between DMI and stimulants in children. In their study, 403 serum concentrations from 142 subjects were examined. Pharmacokinetic parameters were similar for both the DMI and DMI + stimulant groups, including the mean weight-corrected dose (mg/kg), weight and dose-normalized DMI serum concentrations [( ig/L)/ mg/kg], and DMI clearance (L/kg)/hr. 

During a continuous intravenous infusion of V into a subject at 0.27 mg/kg per minute samples of spinal fluid taken at 60 and 150 min after the start of the infusion contained a mean of 68.3% + 2.4% of the serum concentration of the oxime at the same tlme.H subject given an Infusion of 2-PAM I for 60 min at 0.73 mg/kg per minute had a serum concentration of the oxime of 2,8 mg/100 ml at the end of the infusion, but had no detectable concentration of that oxime in the spinal fluid. These findings corroborate the idea that V may have readier access than the pyridinium oximes to the brain. 

Clozapine is metabolized by hepatic CYP 1A2 and, to a lesser degree, CYP 3A3/4 therefore, the drug is subject to changes in serum concentration when combined with medications that inhibit or induce these enzymes. Serum clozapine levels increase with coadministration of fluvoxamine or erythromycin and decrease with coadministration of phenobarbital or phenytoin and with cigarette smoking (Byerly and DeVane 1996). These pharmacokinetic interactions are particularly important because of the dose-dependent risk of seizures. 

Pharmacokinetics The pharmacokinetics of interferon beta-la (Rebif) in patients with multiple sclerosis have not been evaluated. In healthy subjects, a single injection resulted in a peak serum concentration at about 16 hours after administration. The mean serum elimination half-life was 69 hours but varied widely. Following every-other-day subcutaneous injections, an increase in the area under the serum concentration versus time curve (AUC) of approximately 240% was observed. Clearance has been estimated at 33 to 55 liters/h. 

For patients who are treated chronically with parenteral iron, it is important to monitor iron storage levels to avoid the serious toxicity associated with iron overload. Unlike oral iron therapy, which is subject to the regulatory mechanism provided by the intestinal uptake system, parenteral administration, which bypasses this regulatory system, can deliver more iron than can be safely stored. Iron stores can be estimated on the basis of serum concentrations of ferritin and the transferrin saturation, which is the ratio of the total serum iron concentration to the total iron-binding capacity ( ). 

The potential role of the RIA technique in the analysis of BAs was investigated some time ago in a study about the development of a method for the detection of 3/I-hy-droxy-5-cholenoic acid [41]. This technique was considered by the authors to be important in the evaluation of oxidation of the cholesterol side chain, a minor pathway of BA biosynthesis. 3/THydroxy-5-cholenoic acid was found in human meconium [42] and in amniotic fluid [43], suggesting an important role in foetal life. In healthy subjects this compound was found in urine [44] but not in serum [45]. The kidney probably excretes it and its serum concentration is too low to be detected. The aim of this report was to provide a new method for the investigation of the role of 3/T hydroxy-5-cholenoic acid in cholestatic disease. 

Healthy subjects showed serum concentration of 3jS-hydroxy-5-cholenoic acid ranging from 0.08 to 0.45 pmol/l. 

Fluvoxamine increases the systemic availability of oral melatonin, probably by reducing its first-pass clearance (34). In a crossover study in seven healthy subjects, serum melatonin concentrations were increased by fluvoxamine but not citalopram (35). In another study fluoxetine, paroxetine, citalopram, imipramine, and desipramine did not affect the biotransformation of melatonin at therapeutic concentrations in vitro (36). 

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