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Results for “PRETHCAMIDE”

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At least 19 recordsLinked to original sources

PubMed1970

Long-term and short-term effects of oral prethcamide in chronic ventilatory failure.

The effect of oral prethcamide (Micoren) (a mixture of two related amides of crotonyl N' butyric acid) was compared with a placebo preparation in 13 patients with established chronic ventilatory failure. Part I of the study comprised a double-blind single cross-over trial with an initial assessment and two further assessments at the end of each period of one month. Prethcamide was taken in 200-mg. doses four times daily. No subjective or objective changes were noted, and in particular the resting Pco(2) showed no change.Part II of the study comprised a double-blind single cross-over trial of the short-term effect of prethcamide compared with placebo in 12 patients in chronic ventilatory failure. Frequent estimations of mixed venous Pco(2) were made with a rebreathing technique for four and a half hours after ingestion of prethcamide or placebo preparation.Following prethcamide a fall in Pco(2) level to a minimum value at 30 minutes of 93% of control values and persisting for about three hours was noted for the group as a whole. The fall represents a lowering by about 4 mm. Hg of the mixed venous Pco(2).It is concluded that, though in patients with chronic ventilatory failure prethcamide may reduce the Pco(2) in the short term, there is no subjective benefit or observable objective change following repeated administrations over a period of one month.

Aminobutyrates↗

PubMed1997

Pharmacokinetics of intravenous and oral prethcamide in horses.

The respiratory stimulant prethcamide is a mixture of equal parts of crotethamide and cropropamide. A specific and sensitive gas chromatographic method for the determination of crotethamide and cropropamide in horse plasma and urine is described. Both components of prethcamide were extracted from plasma and urine into dichloromethane. The extracts were analyzed by capillary gas chromatography with thermionic detection in the nitrogen-specific detection mode. The lower limits of quantitation were 4.0 ng ml-1 of plasma and 10.0 ng ml-1 of urine. Calibration curves were linear from 2.0-100 ng ml-1 of plasma for both components. Pharmacokinetic parameters for crotethamide and cropropamide after intravenous and oral dosing were estimated by analysis of plasma concentration versus time data. The total plasma clearance of cropropamide was greater than that of crotethamide and both values were greater than 5 ml min-1 kg-1. Renal clearance values of the two drugs were comparable and were much less than estimates of filtration clearance values in horses, indicating extensive re-absorption of both components from the renal tubules. Both compounds were metabolized by N-demethylation of the [(dimethylamino)-carbonyl]-propyl moiety and these metabolites were excreted in urine. The method was demonstrated to be suitable for detecting illicit administration of prethcamide to competition horses.

Administration, Oral↗

PubMedDate not supplied

Characterization of two metabolites of prethcamide by gas chromatography and mass spectrometry.

Crotethamide and cropropamide, both components of the respiratory stimulant prethcamide, are metabolized in humans by demethylation of the [(dimethylamino)-carbonyl]-propyl moiety. The resulting metabolites are characterized by gas chromatography-mass spectrometry of urinary extracts. The use of HCl to prevent losses by volatilization during the evaporation step, combined with methanol as solvent, complicates gas liquid chromatographic analysis of prethcamide. The resulting artifacts are identified.

Administration, Oral↗

PubMed1976

Some behavioral effects of prethcamide compared with those of its two components.

The effects of the two components of prethcamide (namely crotetamide and cropropamide) upon various behaviors in rats were compared with those of prethcamide itself to see if both were active or not and the kind of joint action shown when they were given in combination. Both crotetamide and cropropamide increase the motor activity of rats, reduce the rate of lever pressing in FR and VI food-reinforced schedules and increase the latency times in a multiple CRF-discrimination schedule. When given in combination the drugs show additive effects upon locomotor activity and FR or VI behaviors but they potentiate each other as regards the effects upon latency times in the multiple schedule. On the other hand, a clear antagonism between the two drugs has been found in the acute toxicity test.

Aminobutyrates↗

PubMed1963

Ventilatory effects of prethcamide in healthy young men.

The ventilatory effects of intravenous injections and infusions of prethcamide have been investigated with healthy young adult male volunteers. Ventilatory changes due to the drug were measured at constant inspired Pco(2) or constant alveolar Pco(2), and in relation to the response to changes in alveolar Pco(2). The experiments show that the drug is a mild and somewhat inconstant respiratory stimulant, slow and prolonged in action and liable to give rise to a variety of unpleasant side-effects.

Adult↗

PubMedDate not supplied

Pharmacokinetics of prethcamide following rapid intravenous injection and oral administration in rabbits.

A simple gas chromatographic method for the quantitative determination of ethyl butamide and propyl butamide, the active constituents of the analeptic drug "Prethcamide", in whole blood and tissues has been developed. The method was used to study the disposition of the compounds after iv and po administration to rabbits. The course of changes of ethyl butamide and propyl butamide concentration following rapid intravenous injection and oral administration was described by the two-compartment and one-compartment open models, respectively. The mean half-life (t1/2 beta, min), the body clearance (Clb, 1/min), the mean absorption rate constant (ka, min1-) and tmax (min) values were, respectively: 43.07 +/- 10.54, 0.05 +/- 0.0125, 0.033 +/- 0.0073 and 30.0 +/- 5.0 for ethyl butamide and 30.0 +/- 4.13, 0.0962 +/- 0.0269, 0.0512 +/- 0.0328 and 30.0 +/- 5.0 for propyl butamide. The low bioavailability (F) of the compounds, in the range 24-32%, may be attributed to low absorption of the drugs from the gastro-intestinal tract, or the first-pass effect, or both. The drugs accumulate predominantly in the liver. The faster metabolism and elimination of propyl butamide is postulated.

Administration, Oral↗

PubMed1984

A study on the Prethcamide hydroxylation system in rat hepatic microsomes.

Ethyl butamide and propyl butamide, the active constituents of the analeptic drug named Prethcamide (Ciba-Geigy), undergo biotransformation to respective single metabolites in the presence of rat hepatic microsomes and the NADPH-generating system. Spectral analysis showed that the metabolites were hydroxylated forms of the drug. The hydroxylation was stimulated by NADH and increased ionic strength, and inhibited by the known cytochrome P-450 inhibitors, e.g. SKF-525A, metyrapone, CO and KCN. The drug formed type I binding spectrum with cytochrome P-450.

Aminobutyrates↗

PubMed1964