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Biomedical subjects

C Mokkhavesa

Publications and source records attributed to C Mokkhavesa.

8 recordsLinked to original sources
PubMed2001

Evaluation of Roche Abuscreen ONLINE amphetamine immunoassay for screening of new amphetamine analogues.

Some structural analogues of amphetamine are now important drugs of abuse in Thailand. The utility of the Roche Abuscreen ONLINE reagent amphetamine immunoassay test kit to detect these analogues was studied. The test showed high cross-reactivity to 3,4-methylenedioxyamphetamine (MDA), but low cross-reactivity to its parent drugs, 3,4-methylenedioxymethamphetamine (MDMA) and 3,4-methylenedioxyethylamphetamine (MDEA), as well as to methamphetamine and ethylamphetamine. Also observed in this study was a methamphetamine detection sensitivity enhancement effect of amphetamine, which is the active metabolite of methamphetamine. Correlation between the measured concentration values and the actual amount of these two drugs in the sample was, however, low. Thus, the test can be used to detect methamphetamine only when amphetamine is also present in the sample resulting from either co-administration or metabolism of methamphetamine.

Amphetamine-Related Disorders↗
PubMed1997

Single oral loading dose of phenytoin: a pharmacokinetics study.

In order to determine the optimal single oral loading dose of phenytoin in patients with seizures, a two part study of phenytoin pharmacokinetics was conducted. In the first part, 15 mg/kg of phenytoin was given orally as a single dose to 19 normal medical volunteers with informed consent. Serum concentrations of phenytoin reached the therapeutic level (10 micrograms/ml) with an average of 2.62 +/- 1.25 h. The peak concentrations at 7.26 +/- 4.77 h was 11.95 +/- 2.8 micrograms/ml. The oral loading doses, calculated from a model incorporating a first order of absorption and Michaelis-Menten elimination kinetics to yield the target phenytoin serum concentration of 15 micrograms/ml were 18.7 mg/kg in males and 24.8 mg/kg in females. The larger dose for females is probably required due to the higher total apparent volume of distribution in females than in males. In the second part, seven male and seven female patients with seizures with informed consent received these calculated dosage regimens. For these patients, a single oral loading dose of phenytoin rapidly produced therapeutic concentration (10 micrograms/ml) within an average of 2.04 +/- 0.44 h in males and 2.35 +/- 1.6 h in females with minimal side-effects. For males, the peak concentration at 9.71 +/- 5.94 h was 23.89 +/- 5.46 micrograms/ml and that for females was 21.46 +/- 5.08 micrograms/ml at 7.71 +/- 3.73 h, respectively. Oral loading dose of phenytoin is safe, effective and can be considered in patients who need prompt control of seizures within a few hours, particularly in those areas where medical facilities are limited. It may also replace the intravenous route of phenytoin when the intravenous route is contraindicated.

Administration, Oral↗
PubMed1992

Original versus generic piroxicams, their cost-effective evaluation in rheumatoid arthritis (RA) patients.

This was a 12 week double-blind cross over study of 14 patients with rheumatoid arthritis on the cost-effectiveness of different priced piroxicams. All three drugs affected a significant improvement over baseline measurements in most of the clinical parameters assessed with statistical comparable efficacy. Pharmacokinetic analysis also showed similar properties except for the time to reach maximum concentration which was in favor of drug A. This property may be advantageous in treating acute conditions such as gouty attacks. However, in chronic disease like rheumatoid arthritis, there was no significant difference in pharmacologic and clinical efficacy among the three different piroxicams marketed in Thailand.

Adult↗
PubMed1991

Effect of steroids on cerebrospinal fluid penetration of antituberculous drugs in tuberculous meningitis.

Sixteen patients with oral isoniazid, pyrazinamide, rifampin, and intramuscular streptomycin for tuberculous meningitis were studied. The concentrations of isoniazid, pyrazinamide, rifampin, and streptomycin in cerebrospinal fluid (CSF) obtained 3 hours after administration were 2.40, 34.78, 0.29, and 3.78 micrograms/ml, respectively. The CSF concentrations of isoniazid and pyrazinamide were well above the minimum inhibitory concentration for Mycobacterium tuberculosis. Concentrations of rifampin and streptomycin were above the minimal inhibitory concentration initially but declined below the minimal inhibitory concentration at later times. The CSF penetration of isoniazid, pyrazinamide, rifampin, and streptomycin was about 89%, 91%, 5%, and 20%, respectively. In eight patients who received antituberculous drugs in combination with steroids, the mean CSF and serum concentrations, as well as CSF/serum ratios at various intervals of treatment, were not statistically different (p greater than 0.05) from those of the eight patients who did not receive steroids.

Adult↗
PubMed1990

The blood/cerebrospinal fluid partitioning of pyrazinamide: a study during the course of treatment of tuberculous meningitis.

Concentrations of pyrazinamide were measured in serum and cerebrospinal fluid (CSF) of 17 adult patients with tuberculous meningitis up to six months after starting treatment. Pyrazinamide penetrated excellently into the CSF and mean concentrations at various intervals up to six months of treatment were consistently above that required for inhibition of the growth of Mycobacterium tuberculosis. The blood/CSF partitioning of pyrazinamide does not change as the patients recover from the meningitis.

Adolescent↗