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Biomedical subjects

E Spina

Publications and source records attributed to E Spina.

At least 55 records · Page 3Linked to original sources
PubMed1994

Single dose pharmacokinetics of carbamazepine-10,11-epoxide in patients on lamotrigine monotherapy.

The pharmacokinetics of a single oral dose of carbamazepine-10,11-epoxide (CBZ-E, 100 mg) were compared in 10 patients on chronic monotherapy with lamotrigine (LTG, 200-300 mg/day) and in 10 drug-free healthy control subjects. CBZ-E pharmacokinetic parameters in LTG-treated patients were found to be similar to those observed in controls (half-life: 7.2 +/- 1.6 vs 6.1 +/- 0.9 h; apparent oral clearance: 110.8 +/- 53.1 vs 120.5 +/- 29.9 ml/h/kg; apparent volume of distribution: 1.08 +/- 0.37 vs 1.04 +/- 0.25 l/kg respectively; means +/- s.d.). These data indicate that, contrary to previous suggestions, LTG has no effect on the metabolic disposition of CBZ-E.

Adult↗
PubMed1994

CYP2D6-related oxidation polymorphism in Italy.

The distribution of the oxidation polymorphism related to cytochrome CYP2D6 (debrisoquine type) was determined in 246 healthy Italian volunteers. Phenotyping was based on HPLC determination of the dextrometorphan/dextrorphan concentration ratio (metabolic ratio) in urine samples collected over an 8 h interval following a single oral 30 mg dose of dextromethorphan hydrobromide. Urinary excretion of dextromethorphan showed a wide interindividual variability, ranging from < or = 0.04 to 3.9% and from 0.5 to 79.6% of the dose, respectively. Metabolic ratios ranged from < or = 0.001 to 6.6. Eleven of the 246 subjects showed a metabolic ratio greater than 0.30, indicating that 4.5% of the population could be ascribed to the poor metabolizer status. The frequency of the poor metabolizer phenotype in this population is within the range described for other Caucasian ethnic groups.

Cytochrome P-450 CYP2D6↗
PubMed1994

Inhibition of diazepam metabolism by fluvoxamine: a pharmacokinetic study in normal volunteers.

The effect of fluvoxamine on the pharmacokinetics of diazepam and metabolically derived N-desmethyl-diazepam was investigated in eight healthy volunteers. Each subject received a single oral dose of diazepam (10 mg) in a control session and on the fourth day of a 16-day treatment with fluvoxamine maleate (100 to 150 mg daily). Compared with the control session, concurrent fluvoxamine intake was associated with increased mean peak plasma diazepam concentrations (from 108 to 143 ng/ml, geometric means, difference not significant), with a marked reduction in apparent oral diazepam clearance (from 0.40 to 0.14 ml/min/kg; p < 0.01) and with a prolongation in diazepam half-life (from 51 to 118 hours; p < 0.01). Although peak plasma N-desmethyldiazepam levels were similar in the two sessions, the time required for the metabolite to reach a peak was longer during fluvoxamine intake than in the control session (206 versus 62 hours; p < 0.01). N-Desmethyldiazepam area under the plasma concentration-time curve values were also significantly increased during fluvoxamine treatment. These data suggest that fluvoxamine inhibits the biotransformation of diazepam and its active N-demethylated metabolite. The magnitude of this interaction is likely to have considerable clinical significance.

Adult↗
PubMed1994

Adjunctive fluoxetine in the treatment of negative symptoms in chronic schizophrenic patients.

The effect of adjunctive fluoxetine on negative schizophrenic symptoms was evaluated in 34 chronic schizophrenic in-patients on maintenance therapy with neuroleptics. They received randomly, on a double-blind basis, fluoxetine (20 mg/day) or placebo for 12 weeks. In the fluoxetine group, three patients dropped out because of side effects. Negative symptoms, as measured by change on the Scale for Assessment of Negative Symptoms at the end point compared to baseline values, were significantly improved in fluoxetine-treated patients (p < 0.001), but not in the placebo group. Fluoxetine treatment did not influence positive schizophrenic symptoms, while it induced a slight, but statistically significant, decrease (p < 0.05) in depressive symptoms, as measured by the Hamilton Rating Scale for Depression. Unwanted effects were more common among patients receiving fluoxetine. These data suggest that the addition of fluoxetine to neuroleptic treatment may be beneficial in some schizophrenic patients with negative symptoms.

Adult↗
PubMed1994

Decreased plasma concentrations of imipramine and desipramine following cholestyramine intake in depressed patients.

The effect of cholestyramine (4 g t.i.d. for 5 days) on the steady-state plasma concentrations of imipramine and desipramine was assessed in six depressed patients receiving chronic treatment with imipramine (75-150 mg/day). Compared with baseline, cholestyramine treatment was associated with an average 23% decrease in plasma imipramine levels [from 211 +/- 95 to 159 +/- 67 nmol/L, (mean +/- SD), p < 0.05], whereas desipramine levels decreased only marginally. These data suggest that administration of cholestyramine at therapeutic doses impairs the gastrointestinal absorption of concurrently prescribed imipramine by an extent that is potentially clinically significant.

Adult↗
PubMed1994

Clinical pharmacokinetics of fluvoxamine.

Fluvoxamine is a selective inhibitor of serotonin reuptake that is widely used in the management of depression. Following oral administration, the drug is absorbed efficiently from the gastrointestinal tract. Peak plasma concentrations are usually observed within 2 to 8 hours postdose for capsules and film-coated tablets and within 4 to 12 hours for enteric-coated tablets. Despite complete absorption, oral bioavailability may be incomplete probably because of first-pass metabolism. Approximately 77% of fluvoxamine is plasma protein bound. Only negligible amounts of fluvoxamine are excreted unchanged in urine. The drug is extensively biotransformed, mostly by oxidation, and at least 11 different metabolites have been detected in human urine. None of the metabolites is known to possess significant pharmacological activity. Following administration of single doses, fluvoxamine shows a biphasic elimination with a mean terminal elimination half-life of about 15 to 20 hours. Steady-state plasma fluvoxamine concentrations are achieved 5 to 10 days after initiation of therapy and are 30 to 50% higher than those predicted from single-dose data. Preliminary data also suggest that plasma drug concentrations may increase nonlinearly with increasing daily dosage. The relationship between plasma fluvoxamine concentration and clinical response has not been clearly defined. Fluvoxamine pharmacokinetics are substantially unaltered in the elderly, whereas higher plasma drug concentrations (relative to dose) are observed in patients with alcoholic cirrhosis of the liver. Fluvoxamine inhibits oxidative drug metabolising enzymes and, therefore, causes a number of clinically significant drug interactions. Drugs whose metabolic elimination is impaired by fluvoxamine include tricyclic antidepressants, alprazolam, bromazepam, diazepam, theophylline, phenazone (antipyrine), propranolol, warfarin, methadone and carbamazepine.

Animals↗
PubMed1993

Prevalence of acute dystonic reactions associated with neuroleptic treatment with and without anticholinergic prophylaxis.

The occurrence of acute dystonic reactions was intensively monitored in a population of 646 patients, 379 males and 267 females, aged 18-87 years, consecutively admitted to different psychiatric units and treated with neuroleptics alone or in combination with anticholinergic drugs. Thirty-four patients experienced acute dystonic reactions yielding a total incidence of 5.3%. There was a tendency towards a higher frequency of dystonia in males than in females, and in young patients than in older ones. Patients without anticholinergic medication had a higher frequency of the reaction than those receiving anticholinergic drugs (8.5% vs. 2.8%; p < 0.02). Neuroleptic-induced dystonia was more common in patients treated with butyrophenones than in those receiving phenothiazines or substituted benzamides.

Acute Disease↗
PubMed1993

Effect of fluvoxamine on the pharmacokinetics of imipramine and desipramine in healthy subjects.

The effect of the selective serotonin reuptake inhibitor fluvoxamine (100 mg/day for 10 consecutive days) on the kinetics of a single oral dose of imipramine (50 mg) and desipramine (100 mg) was investigated in 12 healthy subjects. Compared with a control session, treatment with fluvoxamine caused a significant prolongation of imipramine half-life (from 22.8 +/- 6.4 to 40.5 +/- 5.0 h, means +/- SD, p < 0.01) and a marked decrease in imipramine apparent oral clearance (from 1.02 +/- 0.19 to 0.28 +/- 0.06 L/h/kg, p < 0.0001). No significant changes in desipramine kinetics were observed during fluvoxamine treatment. These findings indicate that, at the dosage tested, fluvoxamine markedly inhibits the demethylation of imipramine without affecting significantly the CYP2D6-mediated hydroxylation of desipramine.

Adult↗
PubMed1993

Carbamazepine coadministration with fluoxetine or fluvoxamine.

To study the potential interaction between carbamazepine (CBZ) and selective serotonin reuptake inhibitors, fluoxetine (20 mg/day) and fluvoxamine (100 mg/day) were administered for 3 weeks to eight and seven epileptic patients, respectively, on chronic CBZ treatment. No significant changes in steady-state plasma concentrations of CBZ and its active metabolite, carbamazepine-10,11-epoxide (CBZ-E) occurred, suggesting that CBZ metabolism is probably not affected by fluoxetine or fluvoxamine administration.

Adult↗
PubMed1993

Pharmacokinetic optimisation of tricyclic antidepressant therapy.

Pharmacokinetics has greatly contributed to the elucidation of the variability in clinical response to antidepressants in terms of differences in plasma concentrations due to genetic constitution, age, associated diseases and drug interactions. Despite no general agreement, therapeutic and toxic concentrations have been suggested for some tricyclic antidepressants (TCAs) [amitriptyline, nortriptyline, imipramine, desipramine]. Predictive techniques may be implemented on the basis of which starting TCA dosages may be selected to reach more rapidly those concentrations at which efficacy is more probable. Therapeutic drug monitoring may thereafter assist the clinician in refining the individualisation of the dosage regimen.

Adult↗
PubMed1993

An endocrinological study of patients with primary cutis verticis gyrata.

An endocrinological study of 15 psychiatric patients with primary cutis verticis gyrata (CVG) and 7 control patients was carried out. The investigation of the pituitary-gonadal axis, pituitary-adrenal axis, pituitary-thyroid axis, prolactin and human growth hormone (basal values and circadian biorhythms) did not show any significant difference between the CVG and the control patients. Only levels of free testosterone were significantly lower in patients with CVG than in the control group (p < 0.05), probably reflecting an increased peripheral use of testosterone.

Adult↗
PubMed1993

Evidence of chromosomal fragile sites in schizophrenic patients.

Chromosomal fragility and other chromosomal abnormalities were frequently observed in subjects with neuropsychiatric disorders, such as fragile X syndrome, autism or schizophrenia, but only for the first one the fragility is accepted to be associated to a specific pathology, so that it is used as a diagnostic marker. In this study the authors analyzed 50 schizophrenic males, searching for the rare fragile sites or other aberrations with the method suitable for fra(X) detection. Chromosomes from schizophrenic patients resulted more fragile than those from normal controls, especially chromosome 9. The authors discuss the implications of a possible association of these data with the aetiopathogenesis of schizophrenic syndrome.

Chromosome Fragile Sites↗
PubMed1993

Fluvoxamine-induced alterations in plasma concentrations of imipramine and desipramine in depressed patients.

The effect of fluvoxamine maleate, 100 mg/day for 10 days, on plasma concentrations of tricyclic antidepressants was studied in 15 depressed patients on maintenance therapy with imipramine (7 pts.) or desipramine (8 pts.). In the subgroup treated with imipramine, plasma levels of imipramine increased significantly (p < 0.001) during fluvoxamine coadministration, while levels of desipramine were not modified. Addition of fluvoxamine to patients on a stable desipramine dosage regimen resulted in a slight, but statistically not significant, increase in desipramine plasma concentrations. These results suggest that fluvoxamine is a potent inhibitor of imipramine demethylation, while it has a weak effect on the hydroxylation of desipramine.

Adult↗
PubMed1992

Carbamazepine induced bradycardia--a problem in general or only in susceptible patients? A 24-h long-term electrocardiogram study.

Carbamazepine is a first line drug in the treatment of epilepsy and trigeminal neuralgia, but may exert negative chronotropic and dromotropic effects on the cardiac conduction system. Bradyarrhythmias of different types and severity have been described, especially in the elderly, but the prevalence of arrhythmias in a larger group of carbamazepine treated patients is unknown. Forty-eight patients, 40 years of older, on continuous carbamazepine treatment because of various neurologic disorders were investigated by interview, physical examination, 12-lead surface electrocardiogram, and 24-h long-term electrocardiogram recording. The prevalence of bradyarrhythmias was compared with that in an age-stratified reference group. There was no differences between the two groups, either in the number or the duration of pauses or in the type of pauses. In conclusion, carbamazepine does not increase the risk of bradyarrhythmias in the vast majority of patients.

Adult↗
PubMed1992

Debrisoquine oxidation in an Italian population: a study in healthy subjects and in schizophrenic patients.

The debrisoquine oxidation phenotype was assessed in 137 healthy Italian volunteers and in 41 drug-free schizophrenic patients. A bimodal distribution of the urinary debrisoquine/4-hydroxydebrisoquine metabolic ratio was observed in healthy volunteers. Ten subjects were identified as poor metabolizers, yielding a frequency of 7.3% which is similar to that reported in other European countries. The prevalence of the poor metabolizer phenotype was 9.8% among schizophrenic patients. This indicates that there is no association between polymorphic drug oxidation and schizophrenic disorder. Treatment with chlorpromazine (100 or 150 mg daily) significantly increased the debrisoquine metabolic ratio in nine patients (P less than 0.01). These results confirm that neuroleptics of the phenothiazine class inhibit the oxidative metabolism of debrisoquine.

Adult↗
PubMed1992

Interaction between fluvoxamine and imipramine/desipramine in four patients.

We describe four patients in whom the addition of fluvoxamine (100 mg/day) to the treatment with imipramine or desipramine (100-150 mg/day) resulted in a dramatic increase in the plasma concentrations of the tricyclic antidepressants associated with adverse effects. These observations indicate that fluvoxamine inhibits both the demethylation of imipramine and, possibly to a lesser extent, the hydroxylation of desipramine. The combination of fluvoxamine with tricyclic antidepressants should be avoided whenever possible.

Depressive Disorder↗
PubMed1992

Impairment of carbamazepine-10, 11-epoxide elimination by valnoctamide, a valpromide isomer, in healthy subjects.

The effect of the valpromide isomer valnoctamide (VCD, 200 mg three times daily for 8 days), an over-the-counter tranquillizer, on the elimination kinetics of a single oral dose of carbamazepine-10, 11-epoxide (CBZ-E, 100 mg) was investigated in healthy subjects. During VCD treatment, the half-life of CBZ-E was prolonged significantly compared with control (19.7 +/- 6.7 h vs 6.9 +/- 2.0 h, means +/- s.d., P less than 0.01), and its oral clearance decreased four-fold (from 109.6 +/- 30.7 to 28.8 +/- 11.1 ml h-1 kg-1, P less than 0.01). These findings indicate that VCM, like valpromide, strongly inhibits epoxide hydrolase in vivo.

Administration, Oral↗