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Biomedical subjects

A Fazio

Publications and source records attributed to A Fazio.

At least 55 records · Page 3Linked to original sources
PubMed1988

Evaluation of tricyclic antidepressant plasma levels by an automated enzyme immunoassay (EMIT) in comparison to a high-performance liquid chromatographic method.

A new homogeneous enzyme immunoassay technique (EMIT) for the measurement of plasma levels of amitriptyline, nortriptyline, imipramine, and desipramine was used with an automated procedure and the results were compared to those of a high-performance liquid chromatographic (HPLC) method. Precision of the EMIT test was similar to that of the HPLC method with within-day coefficients of variation in the range of 3.9-10.9% (EMIT) and 3.9-9.6% (HPLC). The day-to-day coefficients of variation ranged from 4.4 to 11.7% for EMIT and from 6.1 to 8.4% for HPLC. Samples from 124 patients were analyzed by both methods and a good correlation was observed for all the four drugs. A paired t test indicated no significant difference for the EMIT and HPLC values. No significant interferences were observed between the tricyclics tested and other commonly associated drugs, such as benzodiazepines and neuroleptics. The new EMIT assay proved to be rapid and easy to perform and showed sufficient reliability and reproducibility to be used for either emergency or routine analysis.

Antidepressive Agents, Tricyclic↗
PubMed1988

Effect of valpromide on the pharmacokinetics of carbamazepine-10, 11-epoxide.

The single oral dose pharmacokinetics of carbamazepine-10, 11-epoxide (CBZ-E) were investigated in six normal volunteers during a control session and during concurrent treatment with valpromide (VPM) (300 mg twice daily for 8 days). VPM caused a prolongation of the CBZ-E half-life from 6.4 +/- 1.4 to 20.5 +/- 6.3 h and decreased CBZ-E clearance from 73.5 +/- 20.0 to 23.5 +/- 4.0 ml h-1 kg-1 (P less than 0.01). These results suggest that the elevation of plasma CBZ-E levels in patients receiving carbamazepine and VPM in combination is due to inhibition of epoxide hydrolase in the liver.

Adolescent↗
PubMed1987

An epidemiological study of the clinical impact of pharmacokinetic anticonvulsant drug interactions based on serum drug level analysis.

The impact of pharmacokinetic anticonvulsant drug interactions on prescribing patterns and serum drug level distribution in a routine clinical setting was evaluated in a population of 848 patients chronically treated with phenytoin, phenobarbital, carbamazepine and valproic acid (either alone or as two-drug combinations) and referred for therapeutic drug monitoring for the first time. While dosages of each drug did not differ significantly between monotherapy and polytherapy patients, significant differences in serum level distribution were found. The proportion of patients with suboptimal serum carbamazepine and valproic acid levels (less than 4 and less than 50 micrograms/ml, respectively) was much greater in the polytherapy than in the monotherapy groups, probably as a consequence of induction of carbamazepine and valproic acid metabolism by combined anticonvulsants. Conversely, the proportion of phenobarbital levels above the upper limit of the optimal range (40 micrograms/ml) was greater among patients receiving phenytoin in combination than among patients taking phenobarbital alone, presumably as a result of phenytoin-induced inhibition of barbiturate metabolism. The therapeutic implications of these findings are discussed.

Adolescent↗
PubMed1987

Large-bowel transit in paraplegic patients.

Severe constipation often follows spinal cord injury. The aim of this study was to evaluate transit of contents through the large bowel in patients with paraplegia after a complete transverse lesion of the spinal cord. Transit through the right colon, left colon, and rectum was evaluated in 11 patients (eight males, 3 females; 17 to 63 years old) and data were compared with that of 37 healthy control subjects. In all patients there was either no, or abnormally low, transit at the level of the left colon and rectum. A minor degree of transit delay at the level of the right colon was also present in eight patients. These data indicate that constipation in patients with paraplegia is due to abnormal transit, mainly at the level of the left colon and rectum, and transection of the spine between the C-4 and T-12 vertebral levels causes alteration of large-bowel motor activity mainly at the level of the segments innervated by the parasympathetic fibers of the sacral outflow.

Adolescent↗
PubMed1987

Fab fragments in the treatment of digoxin overdose: pediatric considerations.

Serious digoxin toxicity due to accidental or deliberate overdose is uncommon, but more than half of the cases reported in 1985 involved children. Toxicity can occur acutely, as with accidental overdose, or with long-term maintenance dosing. In children it is almost always acute. Conventional treatment includes gastric lavage or ipecac-induced emesis, and activated charcoal or nonabsorbable resins and cathartics to reduce absorption. Although children appear to tolerate massive ingestions without specific therapy, serum digoxin levels must be reduced quickly and safely when conventional measures have failed. Fab fragments of digoxin-specific antibodies have been successfully used to treat refractory digoxin toxicity. Indications for use should be limited to life-threatening digoxin toxicity when conventional therapy has failed.

Antibody Specificity↗
PubMed1986

Pharmacokinetics of the antidepressant drug viloxazine in normal subjects and in epileptic patients receiving chronic anticonvulsant treatment.

In order to evaluate the influence of chronic antiepileptic drug treatment on the kinetics of the antidepressant viloxazine (VLX), six drug-free control subjects and six epileptic patients treated with one or two anticonvulsants (phenobarbital, carbamazepine or phenytoin) were given a single oral dose of VLX (200 mg). On a separate occasion, the patients were also given 200 mg VLX by IV infusion. Plasma VLX levels were determined by GLC. Following oral dosing, VLX was rapidly absorbed from the gastrointestinal tract (peak levels at 0.5-4 h); plasma level profiles showed a considerable interindividual variability but did not differ significantly between patients and controls. Terminal half-lives were 4.3 +/- 1.5 h in the patients and 4.3 +/- 1.8 h in the controls. Clearance and volume of distribution calculated after IV dosing in the patients were 124 +/- 11 ml h-1 kg-1 and 0.73 +/- 0.28 l/kg, respectively. The absolute oral availability was 85 +/- 14%. At variance with findings reported for other antidepressants, VLX kinetics do not appear to be significantly altered by concurrent treatment with enzyme-inducing antiepileptic drugs.

Adult↗
PubMed1986

Carbamazepine-viloxazine interaction in patients with epilepsy.

In six depressed epileptic patients stabilised on carbamazepine therapy, addition of the antidepressant agent viloxazine (300 mg/day for three weeks) induced a marked (average 55%) increase in steady-state plasma carbamazepine concentration. The concentration of the active metabolite carbamazepine-10,11-epoxide also increased during viloxazine therapy, but to a lesser extent (16%). In three patients, these effects were associated with symptoms of carbamazepine intoxication, which regressed rapidly when plasma carbamazepine and carbamazepine-10,11-epoxide levels returned to baseline values after discontinuation of viloxazine. In a seventh patient, viloxazine had to be discontinued after only two weeks because of severe side effects associated with a striking elevation of carbamazepine and carbamazepine 10,11-epoxide levels (by 197% and 137% respectively). Although viloxazine appears to be one of the few antidepressants which can be used safely in patients with epilepsy these results indicate that the drug should be prescribed with great caution in subjects treated with carbamazepine. The mechanism of the interaction probably involves inhibition of the metabolism of both carbamazepine and its active epoxide metabolite.

Adult↗
PubMed1984

Single-dose kinetics of primidone in acute viral hepatitis.

The pharmacokinetics of primidone (PRM) after oral administration of a single 500 mg dose was studied in 7 patients with acute viral hepatitis and 7 healthy control subjects. The elimination half-life and the apparent clearance of unchanged PRM in the patients were 18.0 +/- 3.1 h and 42 +/- 14 ml X h-1 X kg-1, respectively (mean +/- SD) and did not differ significantly from the values in the controls (half-life 17.0 +/- 2.4 h; clearance 35 +/- 8 ml X h-1 X kg-1). The metabolite phenylethylmalonamide (PEMA) was detected in the serum of all normal subjects within 2-24 h. By contrast, serum levels of this metabolite were undetectable (less than 2 mumol/1) in all but one of the patients. Serum levels of phenobarbital (PB) remained below the limit of detection (less than 2 mumol/1) in all subjects. The findings indicate that accumulation of PRM with its attendant toxicity is unlikely to occur in epileptic patients who develop acute viral hepatitis, despite evidence that the metabolism of the drug is affected by this condition. The possibility of impaired conversion to PB and its implications are discussed.

Acute Disease↗