[Convulsions after flumazepil]

Two cases of convulsions following intake of the benzodiazepine antagonist, flumazepil, are presented. The etiology is discussed and special precautions are recommended for the diagnostic employment of the preparation.

Changes in serum electrolyte and atrial natriuretic peptide concentrations, acid-base and haemodynamic status after rapid infusion of isotonic saline and Ringer lactate solution in healthy volunteers

Opinions differ on the use of isotonic sodium chloride and Ringer lactate solution for extracellular volume depletion. We have compared changes in serum electrolyte concentrations and acid-base and haemodynamic status after rapid infusion of 2 litre of either isotonic sodium chloride or Ringer lactate solution in healthy volunteers. Changes within groups were small and statistically insignificant. Central venous pressure changes were associated with secretion of atrial natriuretic peptide, but this response was delayed.

Single dose pharmacokinetics and pharmacodynamics of oral oxazepam during concomitant administration of propranolol and labetalol

1. The oral kinetics of oxazepam after a single 15 mg oral dose was investigated in six healthy volunteers before and during concomitant administration of the beta-adrenoceptor antagonists propranolol (80 mg) and labetalol (200 mg) (racemates). 2. A possible pharmacodynamic interaction between oxazepam and the beta-adrenoceptor antagonists was examined using a simple reaction time test (SRT) and by measurement of postural sway. 3. The kinetics of oxazepam were not affected significantly by propranolol or labetalol, although oxazepam and labetalol share the glucuronidation pathway. 4. The SRT was increased by combination of both beta-adrenoceptor antagonists with oxazepam, with the greatest increase after the coadministration of oxazepam with propranolol. Administration of the beta-adrenoceptor antagonists alone had no significant effect. 5. Postural sway was affected significantly only by the combination of oxazepam and propranolol.

Bioavailability and pharmacokinetics of oxazepam

Six healthy volunteers received oxazepam 15 mg i.v. and orally at an interval of at least one week. The kinetic variables of i.v. oxazepam were: elimination half-life (t1/2 beta) 6.7 h, total clearance (CL) 1.07 ml.min-1.kg-1, volume of distribution (Vc) 0.27 l.kg-1 (0.21-0.49) and volume of distribution at steady-state (Vss) 0.59 l.kg-1. The intravenous disposition of unbound oxazepam was characterized by a clearance of 22.5 ml.min-1.kg-1 and a distribution volume of 12.3 l.kg-1. After oral oxazepam the peak plasma level was reached in 1.7 to 2.8 h. The plasma t1/2 beta at 5.8 h was not significantly different from the i.v. value. Absorption was almost complete, with a bioavailability of 92.8%. Urinary recovery was 80.0 and 71.4% of the dose after intravenous and oral administration, respectively. Renal clearance (CLR) of the glucuronide metabolite was 1.10 ml.min-1.kg-1 (0.98-1.52). Oxazepam was extensively bound to plasma protein with a free fraction of 4.5%.

Increased susceptibility to liver disease in relation to alcohol consumption in women

Sex-related differences were prospectively studied in patients with the first presentation of alcoholic liver disease. Among 42 patients the diagnosis was cirrhosis in 8 women and 15 men, alcoholic hepatitis in 4 women and 1 man, steatosis in 6 women and 6 men, and no histologic changes were found in the liver biopsy specimens from 2 men (p greater than 0.1). The median (range) antipyrine clearance was 14.6 (1.0-64) versus 17.2 (3.0-83) ml/min and the clinical score in accordance with the Pugh modification of the Child-Turcotte classification was 8 (5-13) versus 8 (5-11) in the women and men, respectively (p greater than 0.05). In 5 women and only 1 man the antipyrine clearance was less than 5 ml/min, indicating an almost total loss of functional liver mass (p less than 0.05), whereas the Pugh score was above 11 in 6 women, but not in any of the men (p less than 0.05). On an average, the men estimated their total lifetime consumption of alcohol to be 2.1 times greater and the number of days they had consumed more than 5 drinks 2.9 times higher than the women (p less than 0.05). These ratios are reduced to 1.4 and 1.7, respectively (p greater than 0.05), if the female alcohol intake is adjusted to the average male volume of distribution. The results support the concept that women may develop similar, and sometimes even more severe, liver disease after consumption of less alcohol than men. The apparent difference in susceptibility to alcohol may be partly explained by differences in volume of distribution.

Influence of dose and route of administration on disposition of metronidazole and its major metabolites

The influence of dose and route of administration on the kinetics of metronidazole and its major metabolites has been investigated in 8 healthy volunteers given 0.5 and 2.0 g i.v. and p.o. Metronidazole elimination kinetics from plasma could be described by an open two-compartment model. The systemic oral bioavailability of both doses was approximately 1. The total systemic clearance of the intravenous 2.0 g dose was 9% lower than that of the 0.5 g dose (p less than 0.05). There were no significant dose-related differences in volume or rate of distribution. The elimination half-life was similar after the four treatments with metronidazole. The major elimination pathways, renal excretion and hepatic oxidation and glucuronidation, accounted for more than 2/3 of the total systemic clearance. Clearance both by hepatic oxidative metabolism and renal excretion was significantly lower after 2.0 than after 0.5 g i.v., whereas there was no significant difference after the oral doses. The results indicate that a high therapeutic dose of metronidazole may be eliminated at a reduced rate, but this is probably not of clinical importance. No single saturable elimination pathway was identified.